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grover
Jan 23, 2002

PEW PEW PEW
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Local Yokel posted:

How do they work anyway? And why is a single pole switch $2.50, and three way switch $3.50, and a four way switch $14.95? (these prices are for "decor" switch panels). Is there some kind of fancy voodoo behind having three different switches on the same light. It better be able to sync with my phone for that price. :cool:
"Normal" light switches are STST
3-way are SPDT, where one common terminal switches alternately between two travellers
4-way are DPDT, in a criss-cross, where two incoming travellers switch between two outgoing.

You need a 3-way switch where the hot wire enters the first switch from the panel, and a 3-way switch where the hot wire going from the last switch to the light. You need 4-way switches on any switch in-between. You can't use normal 39-cent switches anywhere you want more than one switch to control a light.

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babyeatingpsychopath
Oct 28, 2000
Forum Veteran

The reason for switch prices is supply and demand. A typical house has 100 single-pole switches (a case), 10 3-ways (a box) and 1 4-way (1). They all cost about the same to make, but they make two orders of magnitude more single-pole switches, so the cost comes down.

If you want to control something from one point, you need a single pole. Two points is 2 3-ways. N points is 2 3-ways and N-2 4-ways. Single-pole switches are wired with 2-conductor cable (12/2 or 14/2). Note that there's a ground in the cable, so there are actually three wires in it, but it's still 2-conductor cable. Everything else is with 3-conductor cable (12/3 or 14/3).

Take a lesson from what you're doing now and always run 12/3 from one of your switches to any ceiling lighting box where someone at some point may conceivably want to have a light and a ceiling fan on separate switches. You can always leave the unused wire unconnected.

kid sinister
Nov 16, 2002

Local Yokel posted:

I guess that means that the switches are either giving power to the light & fan, or they are not giving power to the light & fan.
So to be more precise, I guess I was asking if I can control them independently despite not having been wired that way alread, and I suppose that's been answered:

Not necessarily... I was thinking that you had 1 switch to turn on the fan and another to turn on its light. Still, you might not be out of luck! You currently have 3 way switches on either side of the room to turn on that fan. Well, 3 way switches use... 3 way wiring. There are a handful of ways to hook up 3 way switches to control a single device, a couple of which run 3-wire to that device's box. In other words, you might be able to re-purpose your existing wiring to control with a fan speed switch. Unfortunately, the wiring diagrams for those all those methods makes my head spin. You would need to do some testing to see which method you currently have. The only way to determine if you have 3-wire in the ceiling fan's electrical box would be to take the fan down and look for that red wire in its box.

I did a little googling and there are a few 3-way fan speed switches made. Apparently you can turn the fan on/off from either end, but you control the fan speed from one only end. If all else fails, some ceiling fan manufacturers make specialized switch/receiver combos to operate ceiling fans with fewer wires. The receivers are designed to be small enough to be hidden by the fan's canopy. You might have to stick with the same manufacturer for your fan and switch to guarantee the receiver would fit.

Elendil004
Mar 22, 2003

The prognosis
is not good.


Not sure this is the place for it, but I am wondering if a 150amp power line running close to (in the same big pipe underground but not in directly next to each other...maybe 4-6 inches apart) phone lines will cause interference in the phone line.

Also going to be running fiber optic cabling from a satallite internet dish on one house, underground about 400 feet (in the same trunk) and popping out on the otherside to network a house. Any issues with the fiber optic line and the power line? Is there a better line to use (I know catV is limited to 100meters and coax is just pretty 'bleh' isn't it?)? Is there a way to run the phone lines via fiber optic too?

Thanks.

grover
Jan 23, 2002

PEW PEW PEW
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You probably will get a 60Hz hum if you tried this. Also, it's illegal to run communications cables in the same raceway as power cables. There are a few technicalities that may let you get away with it if you're careful, and shielded phone line should mitigate the hum issue.

What sort of conduit are you using for this? If it's as large as you say, it probably isn't "raceway" at all and the code issues are N/A, as you need to run new conduit in the hole anyhow. FYI, for 400', you're going to have to REALLY oversize the cable for voltage drop.

Elendil004
Mar 22, 2003

The prognosis
is not good.


grover posted:

You probably will get a 60Hz hum if you tried this. Also, it's illegal to run communications cables in the same raceway as power cables. There are a few technicalities that may let you get away with it if you're careful, and shielded phone line should mitigate the hum issue.

What sort of conduit are you using for this? If it's as large as you say, it probably isn't "raceway" at all and the code issues are N/A, as you need to run new conduit in the hole anyhow. FYI, for 400', you're going to have to REALLY oversize the cable for voltage drop.

Voltage cable is already run and it's all gravy. There's no applicable codes this is in VT. I didn't build it but the guy who did know's his poo poo he's just not sure about the internet/phone stuff.

Basically they dug a trench and ran a big pipe through it, and ran everything needed through the big pipes in their own littler pipe runs.

Shielded cable isn't a bad idea.

grover
Jan 23, 2002

PEW PEW PEW
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Elendil004 posted:

There's no applicable codes this is in VT.
Oh, you'd better believe there are codes for this stuff! And he's probably already violated several of them. Heh.

Elendil004
Mar 22, 2003

The prognosis
is not good.


grover posted:

Oh, you'd better believe there are codes for this stuff! And he's probably already violated several of them. Heh.

I'm not a contractor but he's been doing this stuff longer than I've been alive, probably longer than you've been alive. So I'll take him at his word. Like I said though, fiberoptics and such are out of his realm of knowledge so I was just trying to gather some info.

I like the idea of shielded phone lines, but is there any reason TO or NOT TO run them fiber optic as well (Can you?)

ohgodwhat
Aug 6, 2005

Elendil004 posted:

I'm not a contractor but he's been doing this stuff longer than I've been alive, probably longer than you've been alive. So I'll take him at his word. Like I said though, fiberoptics and such are out of his realm of knowledge so I was just trying to gather some info.

I like the idea of shielded phone lines, but is there any reason TO or NOT TO run them fiber optic as well (Can you?)

You mean run the phone lines using fiber optic cables? Do you know how fiber optic cables work? I'll assume you do, but I just want to make sure because the way I'm reading it, it doesn't really make sense to me. Also, no, there won't be interference with the fiber optic cables, I don't believe.

Elendil004
Mar 22, 2003

The prognosis
is not good.


ryanmfw posted:

You mean run the phone lines using fiber optic cables? Do you know how fiber optic cables work? I'll assume you do, but I just want to make sure because the way I'm reading it, it doesn't really make sense to me. Also, no, there won't be interference with the fiber optic cables, I don't believe.

Well I'm not too well versed but I know you can go catV to fiber to catV to run a longer internet data connection.

So could you not do the same with a phone line if you wanted to?

grover
Jan 23, 2002

PEW PEW PEW
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Elendil004 posted:

I'm not a contractor but he's been doing this stuff longer than I've been alive, probably longer than you've been alive. So I'll take him at his word. Like I said though, fiberoptics and such are out of his realm of knowledge so I was just trying to gather some info.

I like the idea of shielded phone lines, but is there any reason TO or NOT TO run them fiber optic as well (Can you?)
That doesn't mean he's been doing it right all these years. I see an awful lot of people doing things the wrong way. A disturbing number of contractors in my area have never even seen a code book, letalone know what the building codes are. Duct banks require either strict conformance to designs in the code book (this is NOT one of those designs) or stamped engineering drawings attesting to their design. Which he probably doesn't have, either.

Fiber optics are non-conductive, so there's no issue at all. Fiber optics are usually way more expensive than copper phone lines, so it's rare to see them over such a short distance. There would be 0 interference on fiber optics from the power lines, and 0 chance of a short circuit. And yes, you can go back and forth- data is data, you simply need the right media converters/transceivers.

Messadiah
Jan 12, 2001

Elendil004 posted:

Well I'm not too well versed but I know you can go catV to fiber to catV to run a longer internet data connection.

So could you not do the same with a phone line if you wanted to?

Phone lines have a fair amount of voltage running down them so I doubt it.

Elendil004
Mar 22, 2003

The prognosis
is not good.


grover posted:

That doesn't mean he's been doing it right all these years. I see an awful lot of people doing things the wrong way. A disturbing number of contractors in my area have never even seen a code book, letalone know what the building codes are. Duct banks require either strict conformance to designs in the code book (this is NOT one of those designs) or stamped engineering drawings attesting to their design. Which he probably doesn't have, either.

Fiber optics are non-conductive, so there's no issue at all. Fiber optics are usually way more expensive than copper phone lines, so it's rare to see them over such a short distance. There would be 0 interference on fiber optics from the power lines, and 0 chance of a short circuit. And yes, you can go back and forth- data is data, you simply need the right media converters/transceivers.

It's not what I'd call a duct bank though, who knows. Do you know what fiber optics run per foot? Are there differing grades of cable?

GreenTrench
Jun 19, 2004

Has anyone seen me?

Elendil004 posted:

There's no applicable codes this is in VT.

Five seconds of googling gives me

http://www.dps.state.vt.us/fire/licensing/Electrical.htm

The 2008 NEC is the adopted electrical code.

Lucid Smog
Dec 13, 2004
Easily understood air pollution.

Elendil004 posted:

It's not what I'd call a duct bank though, who knows. Do you know what fiber optics run per foot? Are there differing grades of cable?

There are several different types of fiber optic cable. There are multimode and single mode fibers. Chances are you want multimode fiber for this. The fiber itself is really all the same except for the actual sizes of the fiber (inner and outer jacket measurements). The outer jacketing however comes in many different styles. Cheap, plenum (fire safe), armored, liquid filled for direct burial, etc.

Fiber itself is very inexpensive, though you have to buy thousands of feet for it to be "really" inexpensive. For a 500' run you should be alright. Your problem is going to be terminating and pulling the fiber. Terminating fiber is very expensive and not something you are likely to be able to accomplish on your own, nor will you have the expensive toolset to do so. If you want a custom built to length fiber pre-terminated, it will cost like 500% more than just the fiber itself easily in my experience. Also, you can't just take a 500 foot cable and yank it down the tube. The stress on the cable would likely be too great. You would probably want a wire backed cable so that you could pull the wire, rather than the plastic covered glass.

You will get absolutely no interference in the fiber from electrical or anything else for that matter. However, no, you can't run an analog phone over fiber. Analog phone lines aren't "data" and they carry voltage, which fiber is incapable of doing. There might be some crazy device that will convert analog at both ends for phones, but it would likely be very expensive since they probably only sell like 20 a year. You can run data over the line and use media converters at both ends to get it to get to Cat5 again. You could run VoIP over this data network.

Another thing to consider, though I'm not sure it's totally appropriate for your application: often when running fiber over a decent distance you will run at least 2 pairs of fiber. The fiber is generally inexpensive and the hard part is actually running it. That way if one ever fucks up for some reason you've got a spare already, or if you want more capacity later you can do that.

Also, in regards to the 100m Cat5 distance limitation: you might get away with a longer cable run. Performance will be degraded, for sure, but I would guess that some data would still get through successfully. You would have to decrease the MTU of both link ends though, by a lot. One of the reasons for the 100m limitation is because it guarantees the the "carrier sense" collision detection can work. Basically it means that both ends can't transmit at the same time and not notice that they did this. It has to do with the speed of electrons down the cable and the amount of time it takes to send 1500 bytes over Ethernet.

Lucid Smog fucked around with this message at 03:11 on Apr 13, 2009

Local Yokel
Mar 16, 2005

If the moonshine don't kill me, I'll live 'till I die.
Thanks Kid Sinister, BabyEater, and Grover. I've got a better idea of what I need and what to try. Unfortunately, I spent the day assembling furniture, and hanging towel bars and mirrors, so I didn't get to fiddle with the wiring again yet. Your advice is appreciated and helpful.

Elendil004
Mar 22, 2003

The prognosis
is not good.


thanks for the advice, I might have somebody at work who can terminate the optic cable for me so that might help. Thanks for the advice on the wire-backed cabling, sounds like a good idea.

Morkai
May 2, 2004

aaag babbys
This is a very interesting thread. Thanks to the helpers for your valuable information, and thanks to the askers for covering some of my questions already.

My Situation:

I recently purchased a 76 year old house that has seen multiple upgrades, expansions, and remodels over the years. It has 200A service entering on the southeast corner, and a modern breaker box in the cellar on the northeast corner. The original wiring is K&T, which still exists in the oldest rooms, and the new construction is done (poorly) with Romex cables. Most 3 prong outlets are not actually grounded, but everything that should have GFCI does. I do not know yet if the outlets are not correctly wired, or if a grounding rod has disintegrated.

I understand that I can simply abandon the K&T in the walls and run new Romex through the house, and this is exactly what I intend to do. I fear for my electronics being on ungrounded circuits, and I need some receptacles in places where I have none.

I am very comfortable working with electricity and electrical wiring, I was an electronic technician for about 5 years, and I've worked with some very powerful equipment. I am not, however, knowledgeable about the codes and rules of home power distribution.

I also intend to sell this house in a few years, and I'm trying to do as much labor as I can to improve the resale value. Anything that I have to hire out is a hit to my end return, and I don't want to gently caress up my bottom line any more than is necessary.

My Questions:

Is there any reason why I wouldn't want to break each room down into it's own branch circuit? For example, I have 3 ceiling fans on the second floor that are on one circuit; that is all there is on that circuit. I feel like each fan should be part of the room it resides in, not part of some arbitrary ceiling fan only group. Is that silly of me, or is there some reason to keep it the way it is if I'm going to rewire the entire house?

I want to upgrade my detached garage from a 15A branch to 2x 20A. Am I going to have to dig up the old conduit and bury a second one for the additional circuit? Or can I just pull 2 cables through the existing conduit?

My garbage disposal and dishwasher are connected to a receptacle under the sink, which does seem to be on a GFCI circuit. It seems strange to me that they're not hard wired, especially the disposal. Is there any logical reason for this, or any reason I should not hard wire it the way I think it should be done?

I'm planning on eventually installing an electric on-demand water heater for the master bath (to supplement the existing 40 gallon tank for the whole house), and possibly a heated tile floor. Is there anything out of the ordinary I should do now while I'm working on the rest, to prepare for this thing that may or may not happen next year?

This summer my uncle (who is professional HVAC) is going to replace the furnace and A/C with newer, more efficient, models. The furnace is currently natural gas, but I intend to go electric just to eliminate the ONLY gas appliance in the entire house ($350 a month to heat this bitch in the winter!!). Should I upgrade to 300A or 400A service just to keep some headroom, or should I just squeeze right under the limits and leave the upgrades to the next guy? What does that cost anyway?

I'm not afraid of burning my house down, but I'm afraid of having some inspector come through saying a bunch of my poo poo is wrong and a potential buyer walking away. I think I've got the basic ideas: all wire junctions must be in a box, if a breaker is 20A then every wire, switch, and outlet on that branch needs to be rated 20A also, GFCI if you're X feet from water, outdoors, or in a garage, AFCI in all bedrooms, etc.

What are the easiest mistakes to make that will gently caress me over?

kid sinister
Nov 16, 2002

Morkai posted:

I am not, however, knowledgeable about the codes and rules of home power distribution.
...
Is there any reason why I wouldn't want to break each room down into it's own branch circuit?... is there some reason to keep it the way it is if I'm going to rewire the entire house?

I want to upgrade my detached garage from a 15A branch to 2x 20A. Am I going to have to dig up the old conduit and bury a second one for the additional circuit? Or can I just pull 2 cables through the existing conduit?

My garbage disposal and dishwasher are connected to a receptacle under the sink, which does seem to be on a GFCI circuit. It seems strange to me that they're not hard wired, especially the disposal. Is there any logical reason for this, or any reason I should not hard wire it the way I think it should be done?

I'm planning on eventually installing an electric on-demand water heater for the master bath (to supplement the existing 40 gallon tank for the whole house), and possibly a heated tile floor. Is there anything out of the ordinary I should do now while I'm working on the rest, to prepare for this thing that may or may not happen next year?

This summer my uncle (who is professional HVAC) is going to replace the furnace and A/C with newer, more efficient, models. The furnace is currently natural gas, but I intend to go electric just to eliminate the ONLY gas appliance in the entire house ($350 a month to heat this bitch in the winter!!). Should I upgrade to 300A or 400A service just to keep some headroom, or should I just squeeze right under the limits and leave the upgrades to the next guy? What does that cost anyway?

I'm not afraid of burning my house down, but I'm afraid of having some inspector come through saying a bunch of my poo poo is wrong and a potential buyer walking away. I think I've got the basic ideas: all wire junctions must be in a box, if a breaker is 20A then every wire, switch, and outlet on that branch needs to be rated 20A also, GFCI if you're X feet from water, outdoors, or in a garage, AFCI in all bedrooms, etc.

What are the easiest mistakes to make that will gently caress me over?

Go to the library and look up the National Electric Code. Nearly every city/county/whatever in the US uses this. They update it every 3 years, the most recent edition is 2008.

As for your one circuit per room idea, you're assuming that every room will require one whole circuit. There's rooms like bathrooms and closets whose power needs aren't high enough to require their own distinct circuit. It just isn't cost effective to put rooms like these on separate circuits, running a longer length of romex back to the breaker box instead of to the adjacent room. You'd probably run out of space for breakers in your box before you could pull this off.

As for your conduit question, what size is it? Does it have enough space to run 2 lengths of 12/2? There is actually code on this. In how good of shape is it? Does it leak?

Just try to keep in mind where you'd run pipes and cabling for that on-demand heater and floor, so you won't in the future have to plan around the work you're doing now. You might want to keep a breaker or two open in your box for it.

There's no code that disposals need to be hardwired. In fact, it's actually easier because when a disposal does clog, it's easier to then remove from the sink to take it apart and clear the clog. Still, some inspectors seem to like hardwired disposals for some reason.

Here's the best thing you can do to pass inspection and NOT burn down your house: do your work to code! Unfortunately for the average person, the NEC codebook reads like a law book. That's why people need to train to do this for a living.

grover
Jan 23, 2002

PEW PEW PEW
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kid sinister posted:

Go to the library and look up the National Electric Code. Nearly every city/county/whatever in the US uses this. They update it every 3 years, the most recent edition is 2008.
I'd actually recommend the International Residential Code (IRC) instead. It includes all portions of NEC that's relavant to residential construction and leaves out all the N/A bits that confuse people. It also include all the plumbing, HVAC, etc, that a DIY homeowner needs to know.

There's nothing wrong with grouping a bunch of lights together. You can put them on individual circuits if you'd like, but there's really no reason to, and you'll just waste money in extra breakers and wires and probably need an extra panel at some point. So long as the circuit is sized to support everything on it, you're OK.

Hot water on demand draws a LOT of current- an obscene amount, really. A small one may not be too bad, but a large one is probably just not practical. Just run your tap for 10 seconds like the rest of us ;)

As far as easy mistakes... make sure the right size cable for the circuit (#12 for 20A), make sure to leave 6" of wire in each outlet, and plan ahead- think everything through before you do it! If you plan out every iota of your upcoming upgrades, you'll not be caught by surprise and will have an easier and cheaper time of it. For instance, find out what your water heater demand is, what your new HVAC equipment requires, and do the NEC calculations for your panel to make sure 200A is enough. If not, go from there.

GreenTrench
Jun 19, 2004

Has anyone seen me?

grover posted:


Hot water on demand draws a LOT of current- an obscene amount, really. A small one may not be too bad, but a large one is probably just not practical. Just run your tap for 10 seconds like the rest of us ;)

On demand hot water heaters use less energy than a conventional electrical hot water heater since it doesn't have to keep a giant tank of water warm. But your flow is limited.

Gas hot water heater is cheaper than both though. :)

grover
Jan 23, 2002

PEW PEW PEW
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GreenTrench posted:

On demand hot water heaters use less energy than a conventional electrical hot water heater since it doesn't have to keep a giant tank of water warm. But your flow is limited.
Less energy, but FAR more power; don't confuse the two.

A 150A tankless water heater can only heat about 4 gallons per minute, wheras a 40 gallon water heater can be powered from a 30-40 Amp circuit. It's the difference between brewing a pot of coffee over 5 minutes vs plugging in 6 or 7 coffee pot heating elements in-line, each drawing 15 amps, so you can heat is as you pour the water into your cup. Likewise, you need to double or triple the size of the gas lines to a gas on-demand water heater. It's easy to run the costs way up in the name of energy efficiency. Properly insulated hot water tanks don't even waste that much heat.

grover fucked around with this message at 03:16 on Apr 15, 2009

Morkai
May 2, 2004

aaag babbys

kid sinister posted:

As for your one circuit per room idea, you're assuming that every room will require one whole circuit. There's rooms like bathrooms and closets whose power needs aren't high enough to require their own distinct circuit. It just isn't cost effective to put rooms like these on separate circuits, running a longer length of romex back to the breaker box instead of to the adjacent room. You'd probably run out of space for breakers in your box before you could pull this off.

I wasn't so much thinking of putting closets on individual circuits like that as just putting things together in more logical (to a non-electrician) pattern. A bedroom and it's closet on a single circuit; instead of a bedroom and one outlet in the next room (because they share a wall), minus the ceiling fan (because all upstairs room fans are together on a separate one) just because that's was the absolute most efficient use of wire by a matter of 3 feet. My breaker box can more than handle that as far as space goes. Right now poo poo's totally arbitrary, a mix of the old and the new. I have a breaker that controls just one receptacle in the cellar, with nothing plugged into that. It's insane.

kid sinister posted:

As for your conduit question, what size is it? Does it have enough space to run 2 lengths of 12/2? There is actually code on this. In how good of shape is it? Does it leak?

It looks like it's 1", but I haven't measured. I'm pretty sure I can fit two cables in there, but I didn't know if there was some code for derating the conductors or insulation, etc. It's in great shape that I can see, and does not leak as far as I know. I'll read up on that.

kid sinister posted:

Just try to keep in mind where you'd run pipes and cabling for that on-demand heater and floor, so you won't in the future have to plan around the work you're doing now. You might want to keep a breaker or two open in your box for it.

Check.

kid sinister posted:

There's no code that disposals need to be hardwired. In fact, it's actually easier because when a disposal does clog, it's easier to then remove from the sink to take it apart and clear the clog. Still, some inspectors seem to like hardwired disposals for some reason.

Double check.

kid sinister posted:

Here's the best thing you can do to pass inspection and NOT burn down your house: do your work to code! Unfortunately for the average person, the NEC codebook reads like a law book. That's why people need to train to do this for a living.

I would consider myself ahead of the curve here, considering my past professional experience, but it's still a pretty tall order to make sure I get everything just perfect. I'm mostly just worried about the most obvious oversights and gotchas that an inspector will zero in on and gently caress me.

Thanks for the reply!

Morkai
May 2, 2004

aaag babbys

grover posted:

I'd actually recommend the International Residential Code (IRC) instead. It includes all portions of NEC that's relavant to residential construction and leaves out all the N/A bits that confuse people. It also include all the plumbing, HVAC, etc, that a DIY homeowner needs to know.

Thanks, that sounds very helpful!

grover posted:

There's nothing wrong with grouping a bunch of lights together. You can put them on individual circuits if you'd like, but there's really no reason to, and you'll just waste money in extra breakers and wires and probably need an extra panel at some point. So long as the circuit is sized to support everything on it, you're OK.

I think you misunderstood me on that one. I want the lights to be part of the room they're in (with everything else in the room), rather than 3 lights together with just each other and nothing else. The added expense for those few feet will be negligible.

grover posted:

Hot water on demand draws a LOT of current- an obscene amount, really. A small one may not be too bad, but a large one is probably just not practical. Just run your tap for 10 seconds like the rest of us ;)

This little luxury wouldn't be about how fast the water gets hot for a shower, but to have an unending supply of hot water for 4 people to have showers without being rushed. Like you said they pull a lot of current, but less energy overall than doing a larger tank water heater, or two in series configuration. It also wouldn't be a large model, it only needs to feed the shower, not the whole house.

grover posted:

As far as easy mistakes... make sure the right size cable for the circuit (#12 for 20A), make sure to leave 6" of wire in each outlet, and plan ahead- think everything through before you do it! If you plan out every iota of your upcoming upgrades, you'll not be caught by surprise and will have an easier and cheaper time of it. For instance, find out what your water heater demand is, what your new HVAC equipment requires, and do the NEC calculations for your panel to make sure 200A is enough. If not, go from there.

I'm all about planning. I've sized up everything I intend to do, and I think my 200A service will be just enough. I'm just undecided on if I like the idea of just enough, or if I want to have room for more if some other factor changes. For me personally, I'd want the room, but I don't think a potential buyer is going to think about a maxed out panel vs their future remodeling plans. What does it cost to go all out and hit 400A?

Thanks for you help!

GreenTrench
Jun 19, 2004

Has anyone seen me?

grover posted:

Less energy, but FAR more power; don't confuse the two.

A 150A tankless water heater can only heat about 4 gallons per minute, wheras a 40 gallon water heater can be powered from a 30-40 Amp circuit. It's the difference between brewing a pot of coffee over 5 minutes vs plugging in 6 or 7 coffee pot heating elements in-line, each drawing 15 amps, so you can heat is as you pour the water into your cup. Likewise, you need to double or triple the size of the gas lines to a gas on-demand water heater. It's easy to run the costs way up in the name of energy efficiency. Properly insulated hot water tanks don't even waste that much heat.

Most definitely they are different. I think I misread what was going on.
I thought he wanted to go to an electric hot water heater to save money.

Morkai
May 2, 2004

aaag babbys

GreenTrench posted:

Most definitely they are different. I think I misread what was going on.
I thought he wanted to go to an electric hot water heater to save money.

I just want to augment the capabilities of my existing water heater, and only for the shower in the master bath. Given how well my water heater works, which is already electric and has a 2" added insulation blanket, I can go with one of the smaller 30-50A@120V on-demand types just to boost the temperature after the tank is depleted.

GreenTrench
Jun 19, 2004

Has anyone seen me?

Morkai posted:

This little luxury wouldn't be about how fast the water gets hot for a shower, but to have an unending supply of hot water for 4 people to have showers without being rushed. Like you said they pull a lot of current, but less energy overall than doing a larger tank water heater, or two in series configuration. It also wouldn't be a large model, it only needs to feed the shower, not the whole house.

Tankless hot water heaters don't work in a series configuration. Very few of them throttle the power, and the ones that do have a minimum power output. Because manufacturers don't ever want to put out scalding water, if the temperature coming in is too high (say 90F), the tankless hot water heater won't come on. Not only do you deal with luke warm water, you're susceptible to Legionellosis. A large tankless hot water heater at 3gpm can be fine for a house if you don't have multiple people using hot water at the same time. It all depends on preference and what you're willing to work it.

Morkai posted:

I'm all about planning. I've sized up everything I intend to do, and I think my 200A service will be just enough. I'm just undecided on if I like the idea of just enough, or if I want to have room for more if some other factor changes. For me personally, I'd want the room, but I don't think a potential buyer is going to think about a maxed out panel vs their future remodeling plans. What does it cost to go all out and hit 400A?

Thanks for you help!

Going over 200A isn't that easy. The feeder cables coming in may not be rated for over 200A and may have to be replaced. I've also heard of some utility companies requiring external disconnects for services over 200A.

The cost depends on what area you're in. I've heard of service upgrades as cheap as $500 and go upwards of $3000. As always, get a quote, shop around, and make sure the electrican gets a permit. :)

If you're doing it yourself, you'll need two 200A panels with a wire trough below. The feeder cables from the utility company go into the wire trough and branch off to the two panels. If you are doing this, GET A PERMIT so you can get a cut-in card for your utility company. They'll also come out and cut tag on your meter so you can remove it and not work on live wires. I wouldn't recommend do it yourself though.

Morkai posted:

I just want to augment the capabilities of my existing water heater, and only for the shower in the master bath. Given how well my water heater works, which is already electric and has a 2" added insulation blanket, I can go with one of the smaller 30-50A@120V on-demand types just to boost the temperature after the tank is depleted.

I don't think they go that small. A Stiebel Eltron that'll raise water from 50F to 105F at 3gpm is 24kW.

kid sinister
Nov 16, 2002

Morkai posted:

I have a breaker that controls just one receptacle in the cellar, with nothing plugged into that. It's insane.

That's most likely there for a deep freezer.

babyeatingpsychopath
Oct 28, 2000
Forum Veteran

Ok, first things first: conduit underground. It's against code to put romex in conduit underground. Romex cannot be used in wet locations, and that's what underground counts as (even in conduit). So you're going to be using UF (underground feeder) wire anyway, which is rated for direct burial.

If you can pull the old stuff out, use it to pull in some cable with more conductors. If there's 12/2 in there now, pull in 12/4. If it's 10/2 or 8/2, pull in 10/3 or 8/3.

Next: I had a 60A 240V tankless water heater for the whole house (1200sqft) and it worked fabulously. It would throttle power, take water as hot as 88F, and run all day. It was truly wonderful. If I had to do it on a much larger house, I'd go one of two ways: if there were hot-water floor heat, I'd use a tank heater and a recirculating pump; if not, then a 30A 240V on-demand heater mounted under each sink and a 40A 240V on-demand in the shower(s). That's a lot of wiring, but it's small and reasonably cheap, and you only have half as many water lines.

Upgrading services: ask your power company. Services only come in in 200A, and getting a new one is pretty pricey. It is something you can do, since any half-trained monkey can do residential electric, but it is way more complicated and the service entrance, meter bases, panels, and grounding should probably be done professionally. Once the panels are up, the rest you can do.

Finally, circuiting. When I rewired my house, I read the code book. It said: bathrooms on their own dedicated GFI circuit, two general kitchen appliance circuits with nothing else (no lights, etc) and bedrooms on AFCIs. So that's what I did. I ran two cirucits to the plugs in the kitchen, one circuit to the bathroom, then one circuit to each room in the house. That way, it was easy to turn off "master bedroom" or "living room." Until a room gets really big (10 outlets plus a bunch of lights) a single 20A should do you fine. If you've got space in the panel go for it.

Fridges, disposals, and microwaves are commonly getting dedicated circuits, as are A/C units. Ovens must have a dedicated circuit. That, with the two kitchens, the bathrooms, and the bedrooms on AFCIs, adds up to a lot of circuits really quickly; more quickly with one circuit (two-pole!) per dedicated on-demand water heater.

Lucid Smog
Dec 13, 2004
Easily understood air pollution.

Elendil004 posted:

thanks for the advice, I might have somebody at work who can terminate the optic cable for me so that might help. Thanks for the advice on the wire-backed cabling, sounds like a good idea.

If you know someone who can terminate the fiber, that's great! I have never actually gotten a price on terminations, but I have somewhat guessed that it's around $100 per termination. If you pull four strands, that's eight terminations. Yikes! I couldn't find a link to this one place I found that was pretty well priced and had every kind of fiber cable in bulk you could want. I'm sure I've seen them wire backed before, though some have pulling eyelets that you can use to some effect as well. For your distance and application you're going to want 62.5/125 multimode fiber with either ST or SC terminations (the termination type doesn't really matter, as long as you have either a fiber card in a computer/router/switch or a media converter with the same type of jack).

Regarding the phone line: if you don't want to run 500 feet of phone cable (I'm not even sure you could, the voltage loss over 500 feet of low voltage cable might be a lot) you could pretty easily run VoIP over the fiber data link. Buy an FXO device and put it at your house where the physical POTS line from the phone company is. Put an FXS device at the other end. Buy the same equivalent models from the same company. It should be pretty straightforward to tell the FXS device at the far end that no matter what you mash in for numbers, just forward it to the FXO device. It should also be pretty simple to tell the FXO to just willy-nilly dial out whatever numbers it receives on the POTS line from the FXS device. Then it will appear as though you have normal phone service and none will be the wiser that there's actually a VoIP step in the middle.

Morkai
May 2, 2004

aaag babbys

babyeatingpsychopath posted:

Ok, first things first: conduit underground. It's against code to put romex in conduit underground. Romex cannot be used in wet locations, and that's what underground counts as (even in conduit). So you're going to be using UF (underground feeder) wire anyway, which is rated for direct burial.

If you can pull the old stuff out, use it to pull in some cable with more conductors. If there's 12/2 in there now, pull in 12/4. If it's 10/2 or 8/2, pull in 10/3 or 8/3.

Awesome. I'm not even sure why I didn't think about more conductors in a single cable, I don't really need multiple grounds. I had no idea about UF wire, I'll have to check now and see if that's what I have there now (I suspect it is, the garage looks professionally done).

babyeatingpsychopath posted:

Next: I had a 60A 240V tankless water heater for the whole house (1200sqft) and it worked fabulously. It would throttle power, take water as hot as 88F, and run all day. It was truly wonderful. If I had to do it on a much larger house, I'd go one of two ways: if there were hot-water floor heat, I'd use a tank heater and a recirculating pump; if not, then a 30A 240V on-demand heater mounted under each sink and a 40A 240V on-demand in the shower(s). That's a lot of wiring, but it's small and reasonably cheap, and you only have half as many water lines.

My house is almost 1900sqft, but still only 2 full bath and kitchen to worry about, and those are relatively close to the existing water heater (in terms of pipe feet. I don't have water heated floors, so it sounds like I could go with a good sized tankless for the whole house. Would you mind PMing me details on your tankless?

babyeatingpsychopath posted:

Upgrading services: ask your power company. Services only come in in 200A, and getting a new one is pretty pricey. It is something you can do, since any half-trained monkey can do residential electric, but it is way more complicated and the service entrance, meter bases, panels, and grounding should probably be done professionally. Once the panels are up, the rest you can do.

Sounds like I'll want to stick to my 200A then, if possible, thanks.

babyeatingpsychopath posted:

Finally, circuiting. When I rewired my house, I read the code book. It said: bathrooms on their own dedicated GFI circuit, two general kitchen appliance circuits with nothing else (no lights, etc) and bedrooms on AFCIs. So that's what I did. I ran two cirucits to the plugs in the kitchen, one circuit to the bathroom, then one circuit to each room in the house. That way, it was easy to turn off "master bedroom" or "living room." Until a room gets really big (10 outlets plus a bunch of lights) a single 20A should do you fine. If you've got space in the panel go for it.

That's exactly what my thinking was. I want to be able to just turn off an entire room, like my dining room or something, with one breaker. Not turn off most of it, part of the living room too, only to find that the outlet I want to work with is actually on another circuit because it's on a shared wall. That kind of arbitrary poo poo just confuses and angers me.

babyeatingpsychopath posted:

Fridges, disposals, and microwaves are commonly getting dedicated circuits, as are A/C units. Ovens must have a dedicated circuit. That, with the two kitchens, the bathrooms, and the bedrooms on AFCIs, adds up to a lot of circuits really quickly; more quickly with one circuit (two-pole!) per dedicated on-demand water heater.

I didn't know about the number needed for kitchens, but I still don't think that puts me over the limit. My breaker box is huge for some reason, seems way bigger than what was needed for the house. I'm not complaining though, as it gives me room to expand.

Thanks for your help!

Elendil004
Mar 22, 2003

The prognosis
is not good.


Lucid Smog posted:

If you know someone who can terminate the fiber, that's great! I have never actually gotten a price on terminations, but I have somewhat guessed that it's around $100 per termination. If you pull four strands, that's eight terminations. Yikes! I couldn't find a link to this one place I found that was pretty well priced and had every kind of fiber cable in bulk you could want. I'm sure I've seen them wire backed before, though some have pulling eyelets that you can use to some effect as well. For your distance and application you're going to want 62.5/125 multimode fiber with either ST or SC terminations (the termination type doesn't really matter, as long as you have either a fiber card in a computer/router/switch or a media converter with the same type of jack).

Do you have a link to any resource that describes the different (ST/SC) terminations and the types of fiber? Why is 62.5/125 the best for my uses and what does it mean?

Lucid Smog
Dec 13, 2004
Easily understood air pollution.

Elendil004 posted:

Do you have a link to any resource that describes the different (ST/SC) terminations and the types of fiber? Why is 62.5/125 the best for my uses and what does it mean?

62.5/125 indicates the size of the actual fiber and the jacket, in millimeters. Basically multimode fiber is useful for shorter distances, like less than a few thousand feet. It allows you to use cheaper electronics (like an LED media converter). If you use single mode fiber all the junk that goes along with it will cost more.

Wikipedia has a good article (which also seems to suggest that 50/125 is becoming the new standard since you can use a laser rather than an LED and get 10Gb/s, if that matters to you): http://en.wikipedia.org/wiki/Multimode_fiber

There is also a Wikipedia page on fiber terminations: http://en.wikipedia.org/wiki/Optical_fiber_connector Basically the most common terminations you see on multimode fiber are ST, SC, or LC. There really isn't much difference between them, from your perspective. It's mostly just what type of equipment you have and how many fiber connections you need. For you, ST or SC are good because there is a lot of relatively cheap media converters around that are built for ST/SC terminated 62.5/125 multimode fiber.

SyNack Sassimov
May 4, 2006

Let the robot win.
            --Captain James T. Vader


^^^ I believe you mean microns. Millimeters would mean fiber that's 6.25 cm in diameter...

My house (built in 1976) has 100 amp service. There's a main panel at an outside corner with a 100A and 60A breaker. The 100A goes to a large load center in the garage which basically has all the internal house circuits. The 60A goes either to a subpanel on the side of the house where the aircon unit hooks in, or a subpanel in the back yard for the hot tub.

I'd like to upgrade the service to 200A, and have a few electrical issues and questions.

1. When I moved in the hot tub and air conditioner subpanels (6 ga wire) were both hooked into the same 60 amp breaker on the main panel. I realize technically they probably wouldn't trip the breaker (hot tub is max 30A, aircon is max 50A, although I believe the aircon unit actually uses the incoming amperage to limit its fan, so it's always using 50A), but this seems illegal and unsafe. I removed the aircon wiring from that breaker, but I can't install a new breaker because the bus bars in that panel aren't long enough. Is this something where I can find longer bus bars, or do I have to replace the panel? (If there were longer bus bars they'd have to have mounting holes in the same place or I'd have to drill/tap new ones in the panel).

2. I want to put a new 100A load center in the garage for garage workshop circuits plus any additional circuits in future that I want to run into the house. I've gotten the impression I should be able to run this myself (2 ga wire with at least a 6 ga ground, yes?) and get the electrician who upgrades the service to check off on this as part of the permit he pulls to upgrade the service. Besides following code for the panel and wire run, anything I need to be aware of as regards this plan?

3. I recently put new lights in the garage (and painted it). There used to be two 2-tube T12 fixtures running off 14 ga Romex (stapled to joists, my garage ceiling is unfinished), now there's thirteen 2-tube T8 fixtures in 3 rows of 3, one row of 4, running off 12/2 THHN through EMT to the first fixture in each row, and solid 12/2 MC between fixtures in each row. However, I am an idiot and didn't realize that this would require permits (for some reason, I figured that permits were for "serious" things like running new panels). Also, the new conduit starts from the same place the Romex came out of the wall, which is to say the 14 ga Romex is joined to the THHN in a box there, and it's 14/2 Romex from there to the two switches that control the lights and back to the breaker panel. Unfortunately, that Romex is all in the two sides of my garage that ARE finished (and that I just finished painting). Is this against code to have larger gauge wire further on down the line? I would think it's against code if I upgraded the breaker to 20A or if I'd used smaller gauge than the 14, but joining larger gauge cable after the smaller gauge and with the breaker still at 15A, shouldn't this just be a case of "it's an ugly hack" rather than "it's dangerous"? (Also, nothing else is on that circuit and the lights total 760 watts, so there's no danger of overloading the 15A breaker).

If this does require permits, is this also something I could theoretically get the electrician to sign off on as part of the electrical upgrade? The conduit and cable should all be to code (conduit strapped every 3', all connections in boxes, with boxes and thus conduit grounded to the grounding wire even though I think that's not strictly necessary).

4. Stupid not quite related question - I recently got a 230v compressor (3 HP Marathon Electric continuous duty motor), and I bought a bunch of 10/3 cable to run to it. The house was remodeled shortly before I got it, and they got rid of the second electric oven circuit (and according to the house inspector simply dropped that cable where it was in the crawlspace under the kitchen, hooray for that). That means I have an empty 30A breaker in the current subpanel, which appears to be two 15A bonded together. However, when I hook the compressor into it (one black wire into each breaker, neutral & ground into respective places), it trips the breaker(s) after a minute or so. Is this something I'm not understanding about the breakers (i.e. it doesn't actually work as a 30A but rather trips as soon as one leg pulls more than 15A?), or could it be a problem with the motor trying to pull more than 30A? (I'd understand if it tripped immediately as it would be a current-inrush problem, but it goes usually until the compressor reaches about 30 psi, which makes me wonder if the motor is then pulling more current to drive the pistons and tripping the breaker).

grover
Jan 23, 2002

PEW PEW PEW
:circlefap::circlefap::circlefap:
:circlefap::circlefap::circlefap:
:circlefap::circlefap::circlefap:
:circlefap::circlefap::circlefap:
:circlefap::circlefap::circlefap:
:circlefap::circlefap::circlefap:

Potato Alley posted:

I'd like to upgrade the service to 200A, and have a few electrical issues and questions.

1. When I moved in the hot tub and air conditioner subpanels (6 ga wire) were both hooked into the same 60 amp breaker on the main panel. I realize technically they probably wouldn't trip the breaker (hot tub is max 30A, aircon is max 50A, although I believe the aircon unit actually uses the incoming amperage to limit its fan, so it's always using 50A), but this seems illegal and unsafe. I removed the aircon wiring from that breaker, but I can't install a new breaker because the bus bars in that panel aren't long enough. Is this something where I can find longer bus bars, or do I have to replace the panel? (If there were longer bus bars they'd have to have mounting holes in the same place or I'd have to drill/tap new ones in the panel).
You have two options: replace the panel, or move an existing circuit to a new subpanel, and use the freed up slots to feed the subpanel. Depending on the panel, you might also be able to replace some of the 15 or 20A breakers with piggyback breakers which let you install 2 breakers per slot.

The 60A is probably not going to your outside compressor, but the inside air handler. The electric "emergency heat" element is probably the single highest current draw in your house, with the AC compressor drawing far less. You'd need to pull up the equipment tables for both these items to find out. There's another easy way to tell, too- Got a clamp ammeter?


quote:

2. I want to put a new 100A load center in the garage for garage workshop circuits plus any additional circuits in future that I want to run into the house. I've gotten the impression I should be able to run this myself (2 ga wire with at least a 6 ga ground, yes?) and get the electrician who upgrades the service to check off on this as part of the permit he pulls to upgrade the service. Besides following code for the panel and wire run, anything I need to be aware of as regards this plan?
Depends what kind of wire you're running. If you use romex, you'd need #1 romex. You could use #3 THHN, though, if the terminals are all rated for 90C. If the terminals are 75C, then you'd need #2. You can use #8 ground. It's OK to oversize. In fact, if this is for a garage workshop, you might want to oversize for voltage drop anyhow, even if the lengths are pretty short.

quote:

3. I recently put new lights in the garage (and painted it). There used to be two 2-tube T12 fixtures running off 14 ga Romex (stapled to joists, my garage ceiling is unfinished), now there's thirteen 2-tube T8 fixtures in 3 rows of 3, one row of 4, running off 12/2 THHN through EMT to the first fixture in each row, and solid 12/2 MC between fixtures in each row. However, I am an idiot and didn't realize that this would require permits (for some reason, I figured that permits were for "serious" things like running new panels). Also, the new conduit starts from the same place the Romex came out of the wall, which is to say the 14 ga Romex is joined to the THHN in a box there, and it's 14/2 Romex from there to the two switches that control the lights and back to the breaker panel. Unfortunately, that Romex is all in the two sides of my garage that ARE finished (and that I just finished painting). Is this against code to have larger gauge wire further on down the line? I would think it's against code if I upgraded the breaker to 20A or if I'd used smaller gauge than the 14, but joining larger gauge cable after the smaller gauge and with the breaker still at 15A, shouldn't this just be a case of "it's an ugly hack" rather than "it's dangerous"? (Also, nothing else is on that circuit and the lights total 760 watts, so there's no danger of overloading the 15A breaker).
It's OK to use larger gauge wire than required, and to mix/match. It's not advisable because it's more expensive and can confuse people down the line who might see the #12 and think they can upgrade the breaker to 20A, but it's OK electrically any by code. A lot of people run #12 exclusively, regardless of whether 15A or 20A is planned, for this very reason.

quote:

If this does require permits, is this also something I could theoretically get the electrician to sign off on as part of the electrical upgrade? The conduit and cable should all be to code (conduit strapped every 3', all connections in boxes, with boxes and thus conduit grounded to the grounding wire even though I think that's not strictly necessary).
This requires permits in just about every locality. The solution is easy, though: pull a permit as if you hadn't started the work yet, and then call them back a few weeks later to inspect it :)

quote:

4. Stupid not quite related question - I recently got a 230v compressor (3 HP Marathon Electric continuous duty motor), and I bought a bunch of 10/3 cable to run to it. The house was remodeled shortly before I got it, and they got rid of the second electric oven circuit (and according to the house inspector simply dropped that cable where it was in the crawlspace under the kitchen, hooray for that). That means I have an empty 30A breaker in the current subpanel, which appears to be two 15A bonded together. However, when I hook the compressor into it (one black wire into each breaker, neutral & ground into respective places), it trips the breaker(s) after a minute or so. Is this something I'm not understanding about the breakers (i.e. it doesn't actually work as a 30A but rather trips as soon as one leg pulls more than 15A?), or could it be a problem with the motor trying to pull more than 30A? (I'd understand if it tripped immediately as it would be a current-inrush problem, but it goes usually until the compressor reaches about 30 psi, which makes me wonder if the motor is then pulling more current to drive the pistons and tripping the breaker).
You mean two 15A breakers with a yoke? What you have is not a 30A 240V breaker, it's a 15A 240V breaker. You don't add the phases.

Fire Storm
Aug 8, 2004

what's the point of life
if there are no sexborgs?
Is there any code preventing me from getting a second power drop to my garage? My garage is about 100 feet from my house, and the back of the garage is less than 10 feet from the power pole with transformer on the back of my property. Running underground-grade 4/0 from my house to the garage is quite expensive and I would rather not do that. (Saying 4/0 because the charts I saw said that I need that thick of a cable for my distance to get any real power).

SyNack Sassimov
May 4, 2006

Let the robot win.
            --Captain James T. Vader


grover posted:

You have two options: replace the panel, or move an existing circuit to a new subpanel, and use the freed up slots to feed the subpanel. Depending on the panel, you might also be able to replace some of the 15 or 20A breakers with piggyback breakers which let you install 2 breakers per slot.

Yeah, moving something to the existing subpanel means running it to the garage, which isn't great, and I'd rather not install another new subpanel at the corner of the house. Do they make piggyback breakers in 100A size that I could use in the main panel? I would think that would get unsafe without much thicker bus bars. Sounds like I have to replace the panel.

quote:

The 60A is probably not going to your outside compressor, but the inside air handler. The electric "emergency heat" element is probably the single highest current draw in your house, with the AC compressor drawing far less. You'd need to pull up the equipment tables for both these items to find out. There's another easy way to tell, too- Got a clamp ammeter?

Well, the actual electrical line goes to the outside compressor, or rather to a subpanel near it, which has a 50A breaker installed, and from there into the aircon. It's running through conduit attached to the outside of the house so it's not hard to trace. Didn't know the aircon had an emergency heat element (I guess this would be active if I set the thermo to "cool" and set the temperature to 80?). Unfortunately I don't have a clamp ammeter, keep meaning to get one. I'll look up the equipment and see what it requires.

quote:

Depends what kind of wire you're running. If you use romex, you'd need #1 romex. You could use #3 THHN, though, if the terminals are all rated for 90C. If the terminals are 75C, then you'd need #2. You can use #8 ground. It's OK to oversize. In fact, if this is for a garage workshop, you might want to oversize for voltage drop anyhow, even if the lengths are pretty short.
It's OK to use larger gauge wire than required, and to mix/match. It's not advisable because it's more expensive and can confuse people down the line who might see the #12 and think they can upgrade the breaker to 20A, but it's OK electrically any by code. A lot of people run #12 exclusively, regardless of whether 15A or 20A is planned, for this very reason.

OK. I'd rather oversize as well. Distance is about 40 feet from the main panel to running across the house into the garage, including going up and down the walls. I did want to run #12 exclusively, just didn't want to dig into the wall and fiddle with it, so it'll probably stay as a mixture and if I sell I'll warn the next homeowner.

quote:

This requires permits in just about every locality. The solution is easy, though: pull a permit as if you hadn't started the work yet, and then call them back a few weeks later to inspect it :)

Yeah, I thought this might be a workable solution.

quote:

You mean two 15A breakers with a yoke? What you have is not a 30A 240V breaker, it's a 15A 240V breaker. You don't add the phases.

Yes, two 15s with a yoke. That explains that. So I could just buy a 30A 240V and be done with it, if I decide not to run the subpanel (but then I only have one 30A 240V which isn't enough if I decide to get more 240V equipment, and that may be too much for that panel anyway since it's only getting fed by a 100A breaker and has the rest of the house circuits on it).

Slugworth
Feb 18, 2001

If two grown men can't make a pervert happy for a few minutes in order to watch a film about zombies, then maybe we should all just move to Iran!
Own a home in a Chicago suburb (Berwyn). Looking for some guidance on code.

My detached garage is currently fed by 14g wire on a 15 amp breaker through a 1/2" conduit. My plan is to setup a sub-panel in the garage so that I can run some fairly power-needy welding equipment. I want the sub-panel to be a 60 amp service at 220v. Essentially, I'm wondering two things. What gauge wire do I need to run from my house panel to the garage, and is the 1/2" conduit going to be up to code, or do I need to dig it up and use a larger diameter conduit? I would love to avoid digging up my yard, obviously.

babyeatingpsychopath
Oct 28, 2000
Forum Veteran

Slugworth posted:

Own a home in a Chicago suburb (Berwyn). Looking for some guidance on code.

My detached garage is currently fed by 14g wire on a 15 amp breaker through a 1/2" conduit. My plan is to setup a sub-panel in the garage so that I can run some fairly power-needy welding equipment. I want the sub-panel to be a 60 amp service at 220v. Essentially, I'm wondering two things. What gauge wire do I need to run from my house panel to the garage, and is the 1/2" conduit going to be up to code, or do I need to dig it up and use a larger diameter conduit? I would love to avoid digging up my yard, obviously.

If you're running conduit the whole way (and in Chicago, I'm 99% sure you are) then you can use normal wire (THHN, etc). You're going to need #6 for a 60A subpanel. 3 #6 and 1 #10 ground requires 3/4" conduit minimum, with 1" probably being an easier pull.

As long as you have the ditch in the ground, put another 1" pipe in there just in case you want some phone lines or something.

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Big Steveo
Apr 5, 2007

by astral
As an electrician in Australia, I am horribly confused with all you American talk. As a curiosity, anyone care to give me a low-down on the following:

1. Nominal Voltages; Why is it that Americans use 120v system, and the Centre tap transformer system?

In Australia we use 240v/415v (although Distributors now are converting to 230/400 systems) where 240v is Single phase, 415 is 3 phase. On the street we have 11kv 3-wire Delta circuits transformed into a 415v Phase-Phase Voltage with a neutral to create a Phase to Neutral (single phase) voltage of 240v. 240v powers up a majority of household appliances (Power, Lighting, Ranges, Dishwashers and small air conditioners) while 415v is used for large air conditioning, and other larger appliances. Most domestic sites will only have 240v available.

2. Main Switch Current Ratings; Why so high? 250A is a lot of power. Is it because of the lower Voltages? If so, wouldn't it be smarter to have a system in place where all houses are fed with a higher voltage (eg 240v) to limit the current draw. The main advantage is a smaller conductor size? Again in Australia 2.5mm cable is used for power circuits and is general (depending on factors such as installation conditions, cable length, etc.) can happily supply 20-25A to a circuit. Same with lighting being run in 1.5mm to supply 10-16A. Our Main Switches are 100A.

3. Cable Gauge/Size; What size are your cables, What is #6 gauge? Australia uses cable sizes in the mm^2 system. sort of Insulation do you use? What wires are inside a normal household cables?
Australian Common Cables:

Click here for the full 872x590 image.


Do American cables look like this?

4. Earthing/Grounding: What is your system? Again Australia uses a Multiple-Earthed Neutral (MEN) system which looks like this:

Click here for the full 872x590 image.


How it works:
1: 240v Supply from Supply Authority comes in 2x16mm^2 XLPE (SDI) cable
2. Supply Authority Neutral link is sealed with only authorised electricians allowed to touch, is used for metering purposes.
3. Consumers Neutral Link is linked to the SA N/L where all Final Sub Circuit Neutrals are connected.
4. The N/L has a MEN link to the Earth Bar. This is to prevent the Neutral having a voltage but connecting it to the general mass of earth (deemed to have 0v)
5. Bonding to an Earth Electrode to provide the 0v reference
6. Bonding to Water Pipes to prevent a harmful voltage to the pipe and to protect plumbers.

5. Use of Residual Current Devices (RCD); Do you use them? They are used to provide automatic disconnection of supply in the case of Active to Earth faults.

I'm sure this is a gob full, but I'm curious. They may be follow-up questions.

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