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grover
Jan 23, 2002

PEW PEW PEW
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Slugworth posted:

I got curious and started googling, and found a lot of sites that seem to agree with me, but use a lot of terminology that is over my head.

http://www.rd.com/18099/article18099.html

"As you add up the electrical loads, keep in mind that a wire rated at 15 amps can carry 15 amps all day long. However, 15-amp breakers and fuses can only carry 12 amps—80 percent of their rating—on a continuous basis. Continuous basis is considered to be a circuit loaded to capacity for three hours or more. This 80 percent rule applies to all breakers and fuses."

Again, I might be missing something obvious here. Anyone care to shed some light?
You're both right.

All breakers have a trip curve; they're designed to be able to handle the instantaneous in-rush of electric motors (can be 200%+ load for a fraction of a second when starting) and other brief overload conditions without tripping and won't typically trip under most conditions until somewhere around 125% continuous load. The higher the overload, the faster it will trip. It's possible to put 22A on a 20A breaker and have it for hours and not have it trip. If you've got 18A on a 20A breaker and put a 10A microwave on, it still might not trip for 5 minutes or so. I say "may" because there are a lot of variables here, and trip times can very wildly.

That said, code is that you should not intentionally load a residential breaker more than 80% for long periods of time, as higher continuous loads loads have a chance of nuisance tripping under some conditions, such as high ambient temperatures, and high loads on adjacent breakers. This is because typical residential breakers are pretty stupid; they're not measuring current, they're measuring heat, and unable to distinguish between the heat of an overload (the higher the overload, the faster it heats and quicker it trips) and just ordinary heat. More sophisticated breakers with calibrated programmable trip units can often be loaded safely to near 100%.

The biggest culprits are heat-producing appliances like space heaters, coffee pots, microwaves, hair dryers, etc- anything designed to heat as quickly as possible typically draw as much energy as legally allowed (10-15A on a typical US 3-prong plug). Any of these by itself can take a reasonably loaded circuit and instantly overload it.

grover fucked around with this message at 04:33 on Feb 24, 2010

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kitten smoothie
Dec 29, 2001

My shiny new washer and gas dryer are on a 15A GFI breaker. There's only one receptacle on that circuit. The dryer has a "reverse-action" feature, where every 3 or 4 minutes the drum motor stops to reverses direction. When the motor spins up again it occasionally trips the breaker. By "occasionally" I mean that it may do this once or twice without a problem, but it's not going to make it through a whole dry cycle without tripping.

The label on the dryer says it draws 6.5A, and the washer 7A. The tripping has happened when the dryer was the only load on the circuit (I haven't even tried running both simultaneously).

Is the breaker undersized, or bad altogether? Is a dryer not supposed to be on a GFI? Curious if I should be calling an electrician to check out the panel and possibly replace the breaker, or an appliance repairman to check out the dryer. I'm not comfortable replacing the breaker myself, not so much that I'm afraid of getting killed as I am that I just sunk my life savings into this house and I don't want to burn the place down before I've even owned it for a week.

grover
Jan 23, 2002

PEW PEW PEW
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kitten smoothie posted:

My shiny new washer and gas dryer are on a 15A GFI breaker. There's only one receptacle on that circuit. The dryer has a "reverse-action" feature, where every 3 or 4 minutes the drum motor stops to reverses direction. When the motor spins up again it occasionally trips the breaker. By "occasionally" I mean that it may do this once or twice without a problem, but it's not going to make it through a whole dry cycle without tripping.
When you say breaker, you mean the breaker in your electrical panel, and not the GFCI, right? Assuming that, this sounds like your dryer was overloaded those handful of times. Stalled AC motors are essentially a short-circuit, and let WAY more than 15A of current flow for very brief periods of time. This happens every time you start any motor, but is usually very brief. Same thing as if you try to run large power tools off too long of an extension cord- it can burn out motors, as well as tripping breakers. As I described above, breakers are designed to accommodate this. I suspect what's happening in your case is that when the motor reverses when loaded with an exceptionally heavy load, it has difficulty overcoming the inertia of all those wet clothes, and takes longer than normal to reverse.

The breaker is sized fine for these loads; they're not considered continuous, so it's OK to go up to 15A, and motor starting current doesn't normally count. Washers require GFCI by code, so you can't remove it- regardless, GFCI tripping is a symptom of a problem that needs fixed, and not a problem unto itself.

grover fucked around with this message at 11:55 on Mar 1, 2010

babyeatingpsychopath
Oct 28, 2000
Forum Veteran

grover posted:

When you say breaker, you mean the breaker in your electrical panel, and not the GFCI, right? Assuming that, this sounds like your dryer was overloaded those handful of times. Stalled AC motors are essentially a short-circuit, and let WAY more than 15A of current flow for very brief periods of time. This happens every time you start any motor, but is usually very brief. Same thing as if you try to run large power tools off too long of an extension cord- it can burn out motors, as well as tripping breakers. As I described above, breakers are designed to accommodate this. I suspect what's happening in your case is that when the motor reverses when loaded with an exceptionally heavy load, it has difficulty overcoming the inertia of all those wet clothes, and takes longer than normal to reverse.

The breaker is sized fine for these loads; they're not considered continuous, so it's OK to go up to 15A, and motor starting current doesn't normally count. Washers require GFCI by code, so you can't remove it- regardless, GFCI tripping is a symptom of a problem that needs fixed, and not a problem unto itself.

I'm going to respectfully disagree with this post. GFCIs are notorious for nuisance tripping on motor loads. If it is a GFCI breaker, then replace the breaker with a normal one. Laundry rooms are only required to have GFCI within 6ft of a laundry sink. I suspect it's actually an AFCI breaker, which are much MORE notorious for tripping on heavy motor loads. As far as AFCI goes,

NEC 2008, sec 210.12(B) posted:

All 120-volt, single phase, 15- and 2-ampere branch circuits supplying outlets installed in dwelling unit family rooms, dining rooms, living rooms, parlors, libraries, dens, bedrooms, sunrooms, recreation rooms, closets, hallways, or similar rooms or areas shall be protected by a listed arc-fault circuit interrupter....

So, nothing in there about laundry rooms, either. I don't think a laundry room is considered a closet or other living space.

AbsentMindedWelder
Mar 26, 2003

It must be the fumes.
If I do the digging myself, how much do you suppose it'd cost me to run a 50 amp 220v circuit underground about 125 feet? I already have a breaker and sub panel, so all I really need is cable, conduit, and entrance connectors... I think.

I'm thinking conduit with aluminium inside of it. I'm just trying to get a rough estimate for budgeting purposes. I won't actually be doing this project until the summer time.

kitten smoothie
Dec 29, 2001

grover posted:

When you say breaker, you mean the breaker in your electrical panel, and not the GFCI, right? Assuming that, this sounds like your dryer was overloaded those handful of times. Stalled AC motors are essentially a short-circuit, and let WAY more than 15A of current flow for very brief periods of time. This happens every time you start any motor, but is usually very brief. Same thing as if you try to run large power tools off too long of an extension cord- it can burn out motors, as well as tripping breakers. As I described above, breakers are designed to accommodate this. I suspect what's happening in your case is that when the motor reverses when loaded with an exceptionally heavy load, it has difficulty overcoming the inertia of all those wet clothes, and takes longer than normal to reverse.

The breaker is sized fine for these loads; they're not considered continuous, so it's OK to go up to 15A, and motor starting current doesn't normally count. Washers require GFCI by code, so you can't remove it- regardless, GFCI tripping is a symptom of a problem that needs fixed, and not a problem unto itself.

The dryer's doing this when it's got next to nothing in it. It's a combined GFCI/breaker (there's just a regular receptacle connected to it) so I don't know whether it's tripping due to load or as a result of the GFCI. I'm going to have an electrician check out the breaker tomorrow, and if no go on that, then I'll get the dryer looked at. I've only lived in this house 4 days and it was vacant 7 months before I moved in, so I don't know the history of the wiring but I do know I have a dryer that's just came out of the shrinkwrap.

Somewhere I read that these combined breaker/GFCIs can end up having a lower trip threshold as they age or wear out. is this true?

kitten smoothie fucked around with this message at 17:07 on Mar 1, 2010

Richard Noggin
Jun 6, 2005
Redneck By Default

babyeatingpsychopath posted:

I'm going to respectfully disagree with this post. GFCIs are notorious for nuisance tripping on motor loads. If it is a GFCI breaker, then replace the breaker with a normal one. Laundry rooms are only required to have GFCI within 6ft of a laundry sink. I suspect it's actually an AFCI breaker, which are much MORE notorious for tripping on heavy motor loads. As far as AFCI goes,


So, nothing in there about laundry rooms, either. I don't think a laundry room is considered a closet or other living space.

This brings up something that happened last weekend at my parent's house while they were out of town. They have a sump pump in their basement, connected to a GFCI outlet. They lost power at the house in the middle of heavy rains. Power did not return until the basement had flooded up over the motor of the sump pump. When it did return, it tripped the GFCI, as the motor was underwater and shorting out. My dad did some research and found that sump pumps shouldn't be put on a GFCI because of nuisance tripping, but instead to be connected with an ELCI extension cord (he presumably found that info at http://www.sump-pump-info.com/float-switches.html) . This isn't what happened here, but should he switch to an ELCI?

Regarding backup power to the sump pump - they do have a generator, but it's not an automatic one and wouldn't have helped them in this particular case.

Canuckistan
Jan 14, 2004

I'm the greatest thing since World War III.





Soiled Meat
I'm converting my home range from electric to gas so instead of the 240v outlet I'm using right now I'll need a 120v outlet.

I've already booked an electrician who says the best thing to do is not to remove or change the 240v (for resale reasons) and instead just extend an existing circuit and install a new outlet. I thought that was reasonable since he told me that it'll likely be under $100 to make this happen.

However I just spoke to the gas line installer and he told me that I can just buy an adapter that will essentially just use one of the hot lines on the 240v outlet which will give me my 120v outlet. Total cost of under 10 bucks according to him.

I'm pretty sure that this can't be up to code. Any thoughts?

RedReverend
Feb 15, 2003

Canuckistan posted:

I'm converting my home range from electric to gas so instead of the 240v outlet I'm using right now I'll need a 120v outlet.

I've already booked an electrician who says the best thing to do is not to remove or change the 240v (for resale reasons) and instead just extend an existing circuit and install a new outlet. I thought that was reasonable since he told me that it'll likely be under $100 to make this happen.

However I just spoke to the gas line installer and he told me that I can just buy an adapter that will essentially just use one of the hot lines on the 240v outlet which will give me my 120v outlet. Total cost of under 10 bucks according to him.

I'm pretty sure that this can't be up to code. Any thoughts?

Should be okay. The cable and breaker will be oversized for what it'll actually be drawing, but there isn't anything illegal about that. Just make sure that you detach the other hot wire from your panel and cap it off. Also, replace your double-pole breaker with a single one.

You might have problems if you don't have a neutral though. I haven't connected that many ranges, but I assume that they all have neutrals. If not, then you can retool your second hot and use it as a neutral. Just make sure you wrap white electrical tape around both ends of the wire to identify it as neutral. Then attach it to your neutral/grounding bus at your panel.

grover
Jan 23, 2002

PEW PEW PEW
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RedReverend posted:

Should be okay. The cable and breaker will be oversized for what it'll actually be drawing, but there isn't anything illegal about that. Just make sure that you detach the other hot wire from your panel and cap it off. Also, replace your double-pole breaker with a single one.

You might have problems if you don't have a neutral though. I haven't connected that many ranges, but I assume that they all have neutrals. If not, then you can retool your second hot and use it as a neutral. Just make sure you wrap white electrical tape around both ends of the wire to identify it as neutral. Then attach it to your neutral/grounding bus at your panel.
There is a problem with too large of a breaker; receptacles need overcurrent protection, too. 15A receptacles are only rated for power from 15A or 20A circuit, so you'd have to replace the existing breaker with a 2-pole 15A or 20A breaker if you did this. Would allow for an easy path back to an electric range in the future. And, yeah, make sure you have a neutral!

grover
Jan 23, 2002

PEW PEW PEW
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babyeatingpsychopath posted:

I'm going to respectfully disagree with this post. GFCIs are notorious for nuisance tripping on motor loads. If it is a GFCI breaker, then replace the breaker with a normal one. Laundry rooms are only required to have GFCI within 6ft of a laundry sink. I suspect it's actually an AFCI breaker, which are much MORE notorious for tripping on heavy motor loads.
A motor deteriorating and faulting current to ground- that's no more the fault of the GFCI than a 20A breaker tripping when you put 30A on it. Removing it and replacing with a non-GFCI is no more right than replacing a 20A breaker with a 30A to keep it from "nuisance tripping". That GFCI is not nuisance tripping, it's doing its job. Replace the bathroom fan, old appliance, etc, don't mask the symptom.

The combination of water, grounded sheet metal, and failing motors is dangerous. Even if GFCI aren't necessarily required by code in this specific instance (thought they were, my bad), I'd still highly recommend keeping it. I don't think that's what's at fault here, or it would be tripping randomly. It's not, it's only tripping when the motor reverses, which seems like locked rotor current. It certainly shouldn't be tripping on light load.

Richard Noggin
Jun 6, 2005
Redneck By Default

Richard Noggin posted:

This brings up something that happened last weekend at my parent's house while they were out of town. They have a sump pump in their basement, connected to a GFCI outlet. They lost power at the house in the middle of heavy rains. Power did not return until the basement had flooded up over the motor of the sump pump. When it did return, it tripped the GFCI, as the motor was underwater and shorting out. My dad did some research and found that sump pumps shouldn't be put on a GFCI because of nuisance tripping, but instead to be connected with an ELCI extension cord (he presumably found that info at http://www.sump-pump-info.com/float-switches.html) . This isn't what happened here, but should he switch to an ELCI?

Regarding backup power to the sump pump - they do have a generator, but it's not an automatic one and wouldn't have helped them in this particular case.

Friendly bump here.

dietcokefiend
Apr 28, 2004
HEY ILL HAV 2 TXT U L8TR I JUST DROVE IN 2 A DAYCARE AND SCRATCHED MY RAZR

Richard Noggin posted:

This brings up something that happened last weekend at my parent's house while they were out of town. They have a sump pump in their basement, connected to a GFCI outlet. They lost power at the house in the middle of heavy rains. Power did not return until the basement had flooded up over the motor of the sump pump. When it did return, it tripped the GFCI, as the motor was underwater and shorting out. My dad did some research and found that sump pumps shouldn't be put on a GFCI because of nuisance tripping, but instead to be connected with an ELCI extension cord (he presumably found that info at http://www.sump-pump-info.com/float-switches.html) . This isn't what happened here, but should he switch to an ELCI?

Any ideas what sump pump your parents have? Only reason I ask is the setup at my parents home can handle the primary AC powered pump being completely submerged in water. In fact the float is located on the very top so the thing is always submerged. Unless you have a cheap pump I can't imagine it being underwater was the problem.

The backup pump is a 24v battery powered unit hooked up to two deep cycle batteries. These days I am pretty sure that thing is probably clogged. I have never been able to get it to turn on *ever*. I tried manually flooding the sump area with a hose but after like 4-5 hours with the hose on full it still wasnt bringing the water up past the level required in the sump area. It was just backwashing into the drain tile area around the house.

Richard Noggin
Jun 6, 2005
Redneck By Default
It's a Rigid 1/2HP pump. Not sure of the exact model, but it's definitely not submersible.

kid sinister
Nov 16, 2002
Is it the pedestal kind? Because that style of sump pump isn't water tight...

Richard Noggin
Jun 6, 2005
Redneck By Default
Yes, it's a pedestal. So...GFI or ELCI?

kitten smoothie
Dec 29, 2001

kitten smoothie posted:

The dryer's doing this when it's got next to nothing in it. It's a combined GFCI/breaker (there's just a regular receptacle connected to it) so I don't know whether it's tripping due to load or as a result of the GFCI. I'm going to have an electrician check out the breaker tomorrow, and if no go on that, then I'll get the dryer looked at. I've only lived in this house 4 days and it was vacant 7 months before I moved in, so I don't know the history of the wiring but I do know I have a dryer that's just came out of the shrinkwrap.

Somewhere I read that these combined breaker/GFCIs can end up having a lower trip threshold as they age or wear out. is this true?

Turns out the breaker was an ancient one that wasn't even properly matched to the panel it was installed in. The line from the breaker to the dryer was 12 gauge wire, so we replaced the breaker with a 20amp model and put a GFCI at the receptacle instead of at the breaker. Problem solved.

babyeatingpsychopath
Oct 28, 2000
Forum Veteran

Richard Noggin posted:

Yes, it's a pedestal. So...GFI or ELCI?

From my research, it appears as though the difference between a GFCI and an ELCI is this: GFCI trips 4-6mA, ELCI trips 30-60mA.

I don't think it matters too much, really. All basement outlets have to be GFCI anyway, unless it's a finished basement room, where it's probably going to have to be an AFCI.

grover
Jan 23, 2002

PEW PEW PEW
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Richard Noggin posted:

Yes, it's a pedestal. So...GFI or ELCI?
If a pedestal pump floods, it's going to get all sorts of corrossion and crap up in it and create ground faults which will trip a GFCI breaker. This is why pumps and bathroom fans are so often cited as examples of nuisance trips- it's not a nuisance trip, it's a failed piece of equipment that just has dangerous amounts of current flowing to ground.

The last think you want in your basement is a shock hazard submerged in water. Get a new pump.

Hillridge
Aug 3, 2004

WWheeeeeee!
I'm working on a design for a grid tied 5kW solar array I plan to install on my house. The inverter will need to be connected to my breaker panel via a backfed breaker. My house was built in the 70s and has those awful pushmatic breakers. I have plenty of 20A breakers open since the house was converted from electric to gas heat, but I think I'll need a 30 amp for the inverter.

A few questions:
Would a 30 amp be sufficient?
Can pushmatic breakers still be bought?
Are they rated for backfeeding? This one is real important because I'd need to hook it up this way.

I don't want to add the expense of replacing the whole panel if I don't need to, so are there other options if the pushmatics are unavailable or can't be backfed?

Have any of you done solar installations? I know several electricians, but they don't have any experience with grid tied solar.

One Day Fish Sale
Aug 28, 2009

Grimey Drawer

dv6speed posted:

If I do the digging myself, how much do you suppose it'd cost me to run a 50 amp 220v circuit underground about 125 feet? I already have a breaker and sub panel, so all I really need is cable, conduit, and entrance connectors... I think.

I'm thinking conduit with aluminium inside of it. I'm just trying to get a rough estimate for budgeting purposes. I won't actually be doing this project until the summer time.

I'm also interested in opinions/estimates on this. I'll be doing something similar for my garage that I'm building this summer. I'm planning to run plastic conduit for low-voltage stuff (phone, data, etc.) but haven't decided on power (direct-bury, separate conduit, etc.).

babyeatingpsychopath
Oct 28, 2000
Forum Veteran

dv6speed posted:

If I do the digging myself, how much do you suppose it'd cost me to run a 50 amp 220v circuit underground about 125 feet? I already have a breaker and sub panel, so all I really need is cable, conduit, and entrance connectors... I think.

I'm thinking conduit with aluminium inside of it. I'm just trying to get a rough estimate for budgeting purposes. I won't actually be doing this project until the summer time.

Sorry I missed this. 50A circuit is #8 THHN underground with a #10 grounding conductor. Dedicated 220 with no neutral current means 2 #8s; if you have/need a neutral that's 3 #8s.

As far as conduit: my codebook says you can run 3#8s and a #10 ground in 3/4" sch40 PVC conduit, or 2 #8s and 1 #10 in 1/2" PVC. Whatever you get, get some threaded->threadless couplings and a pair of rigid metal elbows for where you come out of the ground. I'd buy a quart of pulling lube and some pulling string as well. Run your conduit, use a vacuum to suck the string in, tie your wire to the string, and pull. The metal elbows prevent the pull string from cutting through the PVC conduit, which is a concern when pulling big wire in small pipe. Use the lube generously as well. I recommend Polywater A or Polywater CLR. I think Home Depot carries quart bottles of the stuff; sometimes they have Ideal Clearglide, which is OK. Use the whole bottle.

#8 type UF is probably more expensive than conduit and wire, but it is a lot easier to run. You're still going to need to protect the cable where it comes out of the ground with rigid conduit or equivalent.

So cost: (Wire, conduit, rigid 90s, couplings, lube, string) or (8/3 or 8/2 type UF, short pieces of rigid), box, breaker, outlet, tape, maybe some other misc fittings like lock rings.

grover
Jan 23, 2002

PEW PEW PEW
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We should probably mention bury depths, too. Speaking in general (there are lots of exceptions and special rules), rigid conduit and IMC can be just 6" below ground (18" under driveways). PVC must be at least 18" deep. Direct burial cables must be 24" deep.

So, if depth is a problem, you'll need to use stronger pipe. Make sure to get your trench inspected before you backfill, so you don't have to dig it up again later. There are some rules on backfilling, too; you can't necessarily just throw the same dirt back in that you just dug out.

grover fucked around with this message at 03:47 on Mar 6, 2010

dietcokefiend
Apr 28, 2004
HEY ILL HAV 2 TXT U L8TR I JUST DROVE IN 2 A DAYCARE AND SCRATCHED MY RAZR
After putting a hell of a lot more thought into it I realized I really need to be able to put a projection screen in front of my breaker panel. I tried to size the screen smaller and still keep it centered in the room and it is small enough to be pointless for this project. Moving the electrical service to the wall to the right would cost too damned much. :smith:

I hear about people hanging picture frames and all that sort of junk over their panels but nothing really about people putting movie screens in front of it. If my screen is on a hinge at the top or side (swing the entire fucker out into the room for example) is there any problem with this? Previously I was thinking about hinging it at the ceiling and swinging it up an hooking it in place for servicing the backside and stuff.

Here is the thing right now



Shown is the screen with the hinge thing I was thinking about.

EDIT: I also want to mention that I can bring the screen 30" or so off the breaker panel if needed with a custom frame so the screen material would not be in physical contact with the breaker. I have space to work with front to back in that area. I just dont have space side to side to compromise with.

dietcokefiend fucked around with this message at 07:31 on Mar 8, 2010

The Twinkie Czar
Dec 31, 2004
I went for super stud.
I have a fluorescent light fixture in my kitchen that quit working. First I replaced both F40T12 tubes with no effect. Then I put in a new electronic ballast (Philips Advance ICN2S40N) and now the fixture works great - except the ballast gets really loving hot. Is that normal? After 30 minutes of operation the ballast is too hot to touch for more than a second.
I've been trying to convince myself this is normal but I want to follow that "Don't burn you house down" mantra.

dietcokefiend
Apr 28, 2004
HEY ILL HAV 2 TXT U L8TR I JUST DROVE IN 2 A DAYCARE AND SCRATCHED MY RAZR
Running the new circuits for my basement. Currently I have like all the basement lights, outlets, exterior outlets, and garage outlet sharing the same line. :gonk: With the wires strung I will have 15amp for extra basement lights, 20 amp for a projector, 15 amp for aux basement outlets, and 20 amp for theater electronics.

I have like 6 slots still open in the breaker panel. Is there anything "wrong" with those double stuffed breakers that put two things in a single slot? If I go with those I can save about 8 bucks getting two instead of 4.

grover
Jan 23, 2002

PEW PEW PEW
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Not at all, they're a good solution. Just make sure your panel is rated for stacked breakers. Installing a new subpanel is pretty easy, too.

other people
Jun 27, 2004
Associate Christ
I hope this is a good place to ask this. . .

I want to run a new coaxial cable through a wall, and I need to get past the horizontal brace (the "noggin"?) that is between each stud.

As far as I can tell, my two choices are either cut a hole in the drywall near each brace and drill a hole (which I then have to patch :mad:), or use a very long and flexible attachment to drill from the work box hole.

My preference is to buy a long attachment, as patching lots of small holes in the drywall is not something I look forward to. However, I have never used a flexible attachment of that length, and I wonder how I am supposed to know exactly where I am drilling? What is the trick?

dietcokefiend
Apr 28, 2004
HEY ILL HAV 2 TXT U L8TR I JUST DROVE IN 2 A DAYCARE AND SCRATCHED MY RAZR

Kaluza-Klein posted:

I hope this is a good place to ask this. . .

I want to run a new coaxial cable through a wall, and I need to get past the horizontal brace (the "noggin"?) that is between each stud.

As far as I can tell, my two choices are either cut a hole in the drywall near each brace and drill a hole (which I then have to patch :mad:), or use a very long and flexible attachment to drill from the work box hole.

My preference is to buy a long attachment, as patching lots of small holes in the drywall is not something I look forward to. However, I have never used a flexible attachment of that length, and I wonder how I am supposed to know exactly where I am drilling? What is the trick?

:gonk:

Ever had a cement drill bit go limp and slap you in the arm before? Any super long extension that is also flexible is going to turn into a pretzel under any significant amount of torque. It would also be super easy to get misguided after the first stud and end up drill out through the wall down the line.

Can you go down through a floor or up through a ceiling?

babyeatingpsychopath
Oct 28, 2000
Forum Veteran

Kaluza-Klein posted:

I hope this is a good place to ask this. . .

I want to run a new coaxial cable through a wall, and I need to get past the horizontal brace (the "noggin"?) that is between each stud.

As far as I can tell, my two choices are either cut a hole in the drywall near each brace and drill a hole (which I then have to patch :mad:), or use a very long and flexible attachment to drill from the work box hole.

My preference is to buy a long attachment, as patching lots of small holes in the drywall is not something I look forward to. However, I have never used a flexible attachment of that length, and I wonder how I am supposed to know exactly where I am drilling? What is the trick?

Do you have baseboards? If so, take them off, then run your coax at floor level. When you put the baseboard back on, all is hidden.

other people
Jun 27, 2004
Associate Christ
The antenna is basically in the attic above the room with the tv. Baseboards don't really come into it, as far as I reckon.

I can't get the cable under the house to come up through the floor very easily, either. And since this is for an antenna, the shorter the cable the better.

I have the same feelings about those long drill extensions! How in the world do you know where you are drilling?

Maybe I really do have to start poking and covering up holes :/. The wife won't like that unless it is awful pretty!

I suppose I could try a hand-drill? At least that way I won't kill myself with the extension. There has to be some trick to directing it towards the spot you want.

kid sinister
Nov 16, 2002

Kaluza-Klein posted:

I hope this is a good place to ask this. . .

I want to run a new coaxial cable through a wall, and I need to get past the horizontal brace (the "noggin"?) that is between each stud.

As far as I can tell, my two choices are either cut a hole in the drywall near each brace and drill a hole (which I then have to patch :mad:), or use a very long and flexible attachment to drill from the work box hole.

My preference is to buy a long attachment, as patching lots of small holes in the drywall is not something I look forward to. However, I have never used a flexible attachment of that length, and I wonder how I am supposed to know exactly where I am drilling? What is the trick?

Use one of these: http://www.techtoolsupply.com/ProductDetails.asp?ProductCode=65-224

They sell a kit at Home Depot for $50 that has a 1/2" flexible drill bit along with a handle of sorts for guiding the bit in the wall a little more easily, and also some attachments to attach to the bit tip for pulling the cable back through the once you've drilled all the way through.

I would use an old work low voltage box and cut the hole it into your wall first, that will give you a big enough hole to more easily maneuver the bit inside the wall.

GreenTrench
Jun 19, 2004

Has anyone seen me?

Hillridge posted:

I'm working on a design for a grid tied 5kW solar array I plan to install on my house. The inverter will need to be connected to my breaker panel via a backfed breaker. My house was built in the 70s and has those awful pushmatic breakers. I have plenty of 20A breakers open since the house was converted from electric to gas heat, but I think I'll need a 30 amp for the inverter.

A few questions:
Would a 30 amp be sufficient?
Can pushmatic breakers still be bought?
Are they rated for backfeeding? This one is real important because I'd need to hook it up this way.

I don't want to add the expense of replacing the whole panel if I don't need to, so are there other options if the pushmatics are unavailable or can't be backfed?

Have any of you done solar installations? I know several electricians, but they don't have any experience with grid tied solar.

I hope you know what you're doing since installing a PV system is more complicated than most people think.

Yes, you need a 30A breaker. However, if your panel is not rated at least 150A, it'll be a code violation.
You can still get pushmatic breakers. Just not at home depot. You'll have to order online.
All breakers are rated for backfeeding unless they specifically state line and load on them.

There are other options - installing a subpanel from your main service panel. Or you can do a line side tap (although you would need a 60A breaker for that, and then a subpanel with the 30A breaker for inverter.)

If you want, you could send me the design and I'll check it over for you. If you are connecting a grid-tied system, you'll have to file an interconnection agreement with your utility company.

dietcokefiend
Apr 28, 2004
HEY ILL HAV 2 TXT U L8TR I JUST DROVE IN 2 A DAYCARE AND SCRATCHED MY RAZR
Is it wrong to have no fear about working inside a live load center? :ohdear:

I got some permits now to do my work and I am at the stage for rough finishing and rough electrical inspections.

What are they checking with rough electrical? Do my lines have to be all connected and strung along?currently I have my outlet and lighting wiring going roughly to each junction box. Everything is stapled together. The outlet and switch boxes have the wire coiled up and the overhead lighting is sitting with slack at the boxes. The thing mentions connections must be grounded (wont be possible past the first line unless I actually install the outlets/lights entirely). I did pop in my new circuit breakers and installed the wiring in my load center. Neutral/ground connected to the screwdown bars on the side and black wires into the breakers.

Should I be good to go at this point?

Hillridge
Aug 3, 2004

WWheeeeeee!

GreenTrench posted:

I hope you know what you're doing since installing a PV system is more complicated than most people think.

Yes, you need a 30A breaker. However, if your panel is not rated at least 150A, it'll be a code violation.
You can still get pushmatic breakers. Just not at home depot. You'll have to order online.
All breakers are rated for backfeeding unless they specifically state line and load on them.

There are other options - installing a subpanel from your main service panel. Or you can do a line side tap (although you would need a 60A breaker for that, and then a subpanel with the 30A breaker for inverter.)

If you want, you could send me the design and I'll check it over for you. If you are connecting a grid-tied system, you'll have to file an interconnection agreement with your utility company.
Thanks for the advice.

What state(s) are you licensed in?

We have an in-house electrician where I work, and he has strongly recommended that I replace my pushmatics with something more modern. I've thought about doing that long before I started this solar install plan, so I think I'll follow his advice. I already have 200 Amp service (the house used to be electric heat), so that's not a problem. Plus if I do it as part of the solar install I'll get 30% of the cost back from the feds.

I filed the pre-approval for the grid tie, and they responded that they are mostly concerned that the inverter is UL 1741 certified, and sent me some more forms.

I think I've nailed down which inverter I'll be using (Xantrex GT5.0) so now I am picking out the panels and working on the whole system design for the rest of my pre-approval paperwork.

GreenTrench
Jun 19, 2004

Has anyone seen me?

Hillridge posted:

Thanks for the advice.

What state(s) are you licensed in?

We have an in-house electrician where I work, and he has strongly recommended that I replace my pushmatics with something more modern. I've thought about doing that long before I started this solar install plan, so I think I'll follow his advice. I already have 200 Amp service (the house used to be electric heat), so that's not a problem. Plus if I do it as part of the solar install I'll get 30% of the cost back from the feds.

I filed the pre-approval for the grid tie, and they responded that they are mostly concerned that the inverter is UL 1741 certified, and sent me some more forms.

I think I've nailed down which inverter I'll be using (Xantrex GT5.0) so now I am picking out the panels and working on the whole system design for the rest of my pre-approval paperwork.

I'm not licensed. I design these things for a living though (NABCEP certified).

You'll be fine with the GT 5.0. That's a pretty standard inverter, and a good one at that. The only issue I have with it is that the ground fault fuse is a pain in the rear end to get to compared to other inverters and it doesn't have a log of how many hours it's been up and running.

Hillridge
Aug 3, 2004

WWheeeeeee!
What would you recommend for panels, and where should I buy them? I'm looking for the cheapest I can get that are still UL approved and not total crap. I have a 45'x15' area to mount them, so I can afford to trade more area to use cheaper lower wattage panels. I assume buying by the pallet will be the least expensive option per watt. Xantrex has a good system configuration tool on their website where you pick the panel and inverter and it tells you what output you'll get from X strings of Y panels.

GreenTrench
Jun 19, 2004

Has anyone seen me?
You'll probably want Suntech. They're good panels and one of the cheapest out there - Conergy has them. I'd try to stay away from Canadian solar since they're not that great. Yingli is new and they're pretty cheap, but I have zero experience with them.

Here are some dealers you can look at.
Sunwize
DC Power
Focused Energy
Conergy USA

If you have some issues with the dealers, altestore has some suntechs by the pallet that aren't priced too unreasonably.


Xantrex's configuration tool is pretty good. Just remember to put in the record low for your area. Also, NEC 2005 and previous editions didn't recognize manufacturer's specifications for open circuit voltage calculations - you had to use a table. The NEC 2008 changed it and now requires you to use the manufacturer's specifications (this is how xantrex calculates it). Do you know what edition of the NEC is in effect in your area?

Hillridge
Aug 3, 2004

WWheeeeeee!
So long as the panels meet UL1703, I can use them. From what I've see, all but the cheapest Chinese ones do. I'm going to try and buy non-Chinese if I can, though the cost difference may force me to do otherwise. I like Evergreen Solar, but their panels won't allow me to get to 5kW with my inverter.

I'm not sure on which NEC is in effect here. My neighbor is a licensed electrician, and though I plan on doing most of the work myself, I'm going to hire him to help me make sure I build everything to code.

I understand why you need to design to the record low, but it's still annoying because it hasn't been -34°F here in almost 100 years.

Since you design systems, do you have accounts with any of the wholesalers? If so, could I buy through you rather than trying to convince them to sell to me?

We can take this to PM if you want.

Thanks for all the advice!

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GreenTrench
Jun 19, 2004

Has anyone seen me?
Unfortunately I just switched to a company that does large scale systems. I get truckloads of panels straight from distributors.

If you're looking for US panels, you'll want Evergreen or Sharp (although technically sharp's cells are manufactured in Japan). Solon, REC, and Suntech are building plants in the US so panels can be assembled here, and they'll be Buy America compliant.

Have you figured out which racking you're using?

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