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sharkytm posted:Contradiction in terms! Easy to save it when you don't have a lot of it!  stevewm posted:My house is entirely electric with a heat pump. During the winter I've had short periods where basically every high power device in my house was on simultaneously. (water heater, clothes dryer, car charger, heat pump, aux heat strips, dish washer) I've seen 31kW (129A!) peak readouts on my energy monitor during these times. Not sure how accurate it is at high current, but the current clamps are rated up to 200A. Is that averaged / summed across both lines? 200 A at a line-to-line of 220 V is 44 kW theoretically, but since there are many, many more 120 V loads, those will eat at your current limit while delivering less power. In my case, I'm not even sure where my upstream protection is -- I assume the meter has a fuse or something that will blow / pop if I overdraw? What layers of protection are typically installed upstream of the house on the utility side? The hilarious comparison to me is always cars -- a 80 HP Honda Civic is still more power output at the output shaft of the engine than 200 A service at a house. Hard to beat combusting dino juice sometimes.
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Apr 6, 2021 19:42
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movax posted:
The monitor I use (Aeotec Home Energy Monitor G5) has a clamp on each hot of the split phase, and the clamps are directional... one goes "up" and the other goes "down". (https://aeotec.freshdesk.com/support/solutions/articles/6000161943-home-energy-meter-gen5-user-guide-) It is summed. It has options to report each clamp individually, or a summed output of the 2. And it appears to use the voltage of the leg it is plugged into for the wattage calculation.
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Apr 6, 2021 20:30
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movax posted:Easy to save it when you don't have a lot of it! Upstream protection? Everywhere I've seen it's been fuses on the primary side of the transformer. The secondary side has to get really close to a dead short to pop those. If your transformer is sized to serve (say) three houses, then your incoming service lines will happily draw six houses worth of current for an hour or so before the fuses decide that's not good. If the transformer is in bad shape, it'll catch fire slightly before the fuses have decided to blow. Prompt overcurrent protection is on the order of 10,000A for a couple of cycles, (.1 sec) or 20,000A for one cycle (.01 sec).
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Apr 6, 2021 20:33
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babyeatingpsychopath posted:Upstream protection? Everywhere I've seen it's been fuses on the primary side of the transformer. The secondary side has to get really close to a dead short to pop those. If your transformer is sized to serve (say) three houses, then your incoming service lines will happily draw six houses worth of current for an hour or so before the fuses decide that's not good. If the transformer is in bad shape, it'll catch fire slightly before the fuses have decided to blow. Prompt overcurrent protection is on the order of 10,000A for a couple of cycles, (.1 sec) or 20,000A for one cycle (.01 sec). Huh. I am, uh, going to stay further away from the service cables landing on my panel than I have been. Kind of want to back of the envelope the temp-rise of that feed wire now and see how much current I could actually pull...
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Apr 6, 2021 20:39
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movax posted:Easy to save it when you don't have a lot of it! It should be the main breaker(s) in your panel, if it's an older panel it might be up to 6 big breakers in a "split bus" arrangement. The meter is unprotected. babyeatingpsychopath posted:Upstream protection? Everywhere I've seen it's been fuses on the primary side of the transformer. The secondary side has to get really close to a dead short to pop those. If your transformer is sized to serve (say) three houses, then your incoming service lines will happily draw six houses worth of current for an hour or so before the fuses decide that's not good. If the transformer is in bad shape, it'll catch fire slightly before the fuses have decided to blow. Prompt overcurrent protection is on the order of 10,000A for a couple of cycles, (.1 sec) or 20,000A for one cycle (.01 sec). The secondary side of utility transformers is a really fascinating setup, it's about the one area where the conductors and transformer are essentially unprotected by selective tripping, and proper fusing for conductor protection. That big primary fuse is there solely to protect the Medium Voltage (4160V, 7.5, 23, or 33kV) distribution wire, and it'll sit there and let the service drops cook off from a direct short, spraying molten copper everywhere until a splice opens or the transformer catches fire (which is quite a show to watch). Basically that 1/0 triplex (or whatever) is its own fuse.
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Apr 6, 2021 20:43
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movax posted:Huh. I am, uh, going to stay further away from the service cables landing on my panel than I have been. Kind of want to back of the envelope the temp-rise of that feed wire now and see how much current I could actually pull... You should consider everything upstream of your home panel main breakers to be entirely unfused as it's not trying to protect you but upstream equipment. One of those pole hung transformers exploding is exciting to see, but remember they're filled with now on fire oil.
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Apr 6, 2021 20:55
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Elviscat posted:It should be the main breaker(s) in your panel, if it's an older panel it might be up to 6 big breakers in a "split bus" arrangement. The meter is unprotected. Elviscat posted:It should be the main breaker(s) in your panel, if it's an older panel it might be up to 6 big breakers in a "split bus" arrangement. The meter is unprotected. I will grab a picture later tonight to see if I am incredibly blind, but I don't think I have any 'main' breakers inside my house / on the panel -- incoming service wires come out of a conduit in the floor. No way to actually de-energize the A/B bars in my main panel, unless it is outside somewhere in a box near the meters. Panel construction / install date as far as I know would have been 1984.
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Apr 6, 2021 21:58
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I've been in this business for 15 years and I've only seen (the aftermath) of 3 transformers that explosively blew up. In all cases, they had a slow oil leak for a very long time, and the sudden internal fault built up pressure faster than the protective fuse could melt, or the release valve could relieve it (obviously, lol). Fun fact - they're designed to blow the top off instead of rupturing the side or bottom via a sacrificial ring that joins the tank and lid. This contains the oil somewhat and keeps the core inside the case. On one of those occasions, we never did locate the lid. Most secondary faults will self-clear. Granted, you don't want to be near that arc fault when it happens. This is why I'm a big fan of exterior main breakers right at the meter. No reason for that fault current potential to be inside your house. Elviscat posted:The secondary side of utility transformers is a really fascinating setup, it's about the one area where the conductors and transformer are essentially unprotected by selective tripping, and proper fusing for conductor protection. The primary fuse does protect the transformer as well, or at least they should. Transformers are rated (depending on manufacturer I suppose) to run at 150% of stated kw for a period of time. That's what my utility fuses at. As noted though - that's a lot of power and it takes a lot of secondary fault current to pop the fuse. Just because (say) your panel buswork has faulted and is making a big light and noise show, it doesn't mean the transformer is negatively affected. It's just seeing some increased load
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Apr 6, 2021 22:44
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Just spent $500 on a generator interlock kit and some GFCI/AFCI breakers. Burning money so my house doesn't. 
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Apr 6, 2021 22:54
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stevewm posted:The monitor I use (Aeotec Home Energy Monitor G5) has a clamp on each hot of the split phase, and the clamps are directional... one goes "up" and the other goes "down". (https://aeotec.freshdesk.com/support/solutions/articles/6000161943-home-energy-meter-gen5-user-guide-) On split phase 240vac, you wouldn't sum the amp reading on the two legs. I'm assuming they're pretty close (hopefully your 120v loads aren't way out of balance); just take the higher reading and use that number. This is because your 240v loads are a circuit on the whole 240v service. If your electric dryer pulls 17A, you will read 17A load on both legs and as far as the breaker/meter/service conductor/transformer is concerned it is feeding 17A.
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Apr 6, 2021 22:56
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angryrobots posted:On split phase 240vac, you wouldn't sum the amp reading on the two legs. I'm assuming they're pretty close (hopefully your 120v loads aren't way out of balance); just take the higher reading and use that number. I just assumed it was... I guess not! I just know it offers reports showing each clamp individually and then a "total readings" report, which is the one I use. And it appears to be accurate. 240v loads read correctly as do 120v loads.
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Apr 7, 2021 02:44
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n0tqu1tesane posted:This is exactly why we are not, under any circumstances, buying this house at this point. The head of the sellers agent's real estate office called our agent yesterday asking if we would still close if they had the work permitted and inspected by the city. I had to laugh, because I am pretty sure they're grasping at straws now since the sellers aren't going to be able to close on their new house since it was likely contingent on closing on this sale. If they hadn't repeatedly lied to us, and done the work they agreed to do properly the first time, they wouldn't be in this situation.
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Apr 7, 2021 16:34
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n0tqu1tesane posted:The head of the sellers agent's real estate office called our agent yesterday asking if we would still close if they had the work permitted and inspected by the city. I love lovely people reaping their own lovely actions. I bet their agent is furious with them too because them trying to save a couple hundred bucks (and lying about it) has cost everyone thousands and thousands. 
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Apr 7, 2021 16:42
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SpartanIvy posted:I love lovely people reaping their own lovely actions. I bet their agent is furious with them too because them trying to save a couple hundred bucks (and lying about it) has cost everyone thousands and thousands. Their agent texted my agent saying things such as "they could have saved money with a different contract" and "they've already spent $2800 on fixes for the seller and can't spend any more". At least a third of that $2800 was partially fixing the standby generator that the seller listed as a feature of the home but knew was non-functional, and then signed a contract stating all the electrical equipment in the house was in good working condition. The house has been listed again, and they're still listing the generator as a feature of the house.
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Apr 7, 2021 16:50
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n0tqu1tesane posted:Their agent texted my agent saying things such as "they could have saved money with a different contract" and "they've already spent $2800 on fixes for the seller and can't spend any more". I'm sure they'll find a sucker. There's a lot of them out there buying homes right now.
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Apr 7, 2021 16:59
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n0tqu1tesane posted:Their agent texted my agent saying things such as "they could have saved money with a different contract" and "they've already spent $2800 on fixes for the seller and can't spend any more". Have you told the city about the unpermitted unlicensed work done on aluminum wiring in the house along with those pictures? Because I'm
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Apr 7, 2021 17:10
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The directions for my cook top show the ground for the appliance connecting to the screw in the junction box, alongside the ground wire from the house's circuit. That seems... rather a tight fit. Will a wire hit at their ends be fine?
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Apr 8, 2021 01:06
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hooah posted:The directions for my cook top show the ground for the appliance connecting to the screw in the junction box, alongside the ground wire from the house's circuit. That seems... rather a tight fit. Will a wire hit at their ends be fine? You need to take a picture of what you're looking at in these directions, because it sounds like some deeply fundamental misunderstandings at this point.
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Apr 8, 2021 01:17
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Motronic posted:You need to take a picture of what you're looking at in these directions, because it sounds like some deeply fundamental misunderstandings at this point. Phone posting, so sorry if this is huge. 
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Apr 8, 2021 01:22
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Okay, that may look like the box you've already got, and that's reasonable if you do. It might not. More importantly, there are new cooktops that are still direct wire? I didn't know that was a thing anymore. Or is this an old cooktop and you're doing something you probably shouldn't be? Also, please explain what "Will a wire hit at their ends" means. Like, really, don't try to be coy. If you want help tell us what the hell you're doing.
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Apr 8, 2021 01:27
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The ground wires have to be connected to each other. If the junction box is metal, it has to be connected to the ground wire. Wire nutting the two ground wires + a pigtail that connects to the box screw is fine if that's what you have to do.
shame on an IGA fucked around with this message at 01:32 on Apr 8, 2021 |
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Apr 8, 2021 01:29
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Motronic posted:Okay, that may look like the box you've already got, and that's reasonable if you do. It might not. Oh jeez, thanks autocorrect. That was supposed to be "Will a wire nut at their ends be fine?" So this is a new cooktop. At least, within the last year, maybe two. I bought it new from Amazon, at any rate. shame on an IGA posted:The ground wires have to be connected to each other. If the junction box is metal, it has to be connected to the ground wire. Wire nutting the two ground wires + a pigtail that connects to the box screw is fine if that's what you have to do. Yeah, it'll be connected to the ground wire either way. I just wasn't sure if I should try to mash both the house's ground wire and the cooktop's into the screw in the junction box, or leave the house's wire connected to the screw and then use a wire nut on the ends of the ground wires.
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Apr 8, 2021 01:29
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hooah posted:Oh jeez, thanks autocorrect. That was supposed to be "Will a wire nut at their ends be fine?" Okay, all of a sudden this makes so much more sense. Yes, that will be fine. They just need to be connected. It doesn't have to be under a screw. As long as all of that is in the box. I'm still surprised direct wire cooktops are a thing. I thought all appliances had gone to plugs by now.
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Apr 8, 2021 01:32
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Motronic posted:Okay, all of a sudden this makes so much more sense. Yeah, I wish they had. But then I'd be up a different creek because I'd have to pay a professional to install the correct outlet, because that seems out of my league (which is mostly ceiling fan installations).
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Apr 8, 2021 01:33
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Check my edit: "as long as it's all in the box"  Just making sure here.
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Apr 8, 2021 01:34
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the outlet would have the same connections as the bare cable and you've already got a box there why would that be harder
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Apr 8, 2021 01:36
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Motronic posted:Check my edit: "as long as it's all in the box" Oh, yeah, definitely. I know that I don't know much, but I know that wires go back where they came from! (I.e. the wires from the house were all in the box to begin with, so everything should be hidden in there at the end.)
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Apr 8, 2021 01:36
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hooah posted:Yeah, I wish they had. But then I'd be up a different creek because I'd have to pay a professional to install the correct outlet, because that seems out of my league (which is mostly ceiling fan installations). If you can install a ceiling fan you can certainly install an outlet in an existing box... there's not really much difference.
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Apr 8, 2021 01:50
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hooah posted:Yeah, I wish they had. But then I'd be up a different creek because I'd have to pay a professional to install the correct outlet, because that seems out of my league (which is mostly ceiling fan installations). If you can direct wire you have more skill than it takes to install an outlet. Because the hard part is the wire nuts. And bending #10 wire. Or whatever you have.
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Apr 8, 2021 01:51
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Thanks for the votes of confidence, folks. Also, the cooktop is installed and works great! Thank you for the help and advice over the last month.
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Apr 8, 2021 02:20
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Another thread success story.
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Apr 8, 2021 02:54
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H110Hawk posted:Have you told the city about the unpermitted unlicensed work done on aluminum wiring in the house along with those pictures? Because I'm I'm tempted to, but until we're completely released, I'd rather not poke that bear.
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Apr 8, 2021 04:02
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n0tqu1tesane posted:I'm tempted to, but until we're completely released, I'd rather not poke that bear. Sure, but like, you're not going to be a huge disappointment to us right? You wouldn't let down your internet friends like that would you?
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Apr 8, 2021 04:25
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So for planning the rewiring of my house, I think I've got most of my circuits laid out like I want. The kitchen is currently planned to have 5 circuits. 2 dedicated countertop circuits, a dedicated microwave circuit, a dedicated refrigerator circuit, and a final circuit for the dishwasher, sink disposal, and the ventilation hood and light. I'm debating throwing the refrigerator on that last circuit too, so I'm open for opinions on that. Everything is going to be GFCI/AFCI breakers. But my main question is how to go about wiring this up. I will be feeding THWN wire from my outdoor panel through a few feet of conduit and then into my crawlspace where it will end in a junction box right inside. From there I will use Romex to run it to the kitchen, which is where my conundrum lies. Typically the romex would go straight up to one of the receptacles and then daisy chain from there to the other receptacles. I'm wondering if it makes more sense to have a second junction box or two under the kitchen, and have the romex supply wires split off from there to feed the various receptacles they need to. I think this would be a better solution for retrofitting because it means I only need to fish 1 romex cable from each receptacle into the crawl space, and when I remodel my kitchen in the future it will make it so easy to move the electrical pieces that need to be moved. Also, my kitchen does not yet have a sink disposal or dishwasher, so those couldn't be run yet anyway, but I could run the wiring for the rest of the circuit and then pigtail them into the circuit in the junction box as they are installed.
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Apr 8, 2021 04:34
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SpartanIvy posted:
Run one 12/3 20a double pole cfci and install an outlet under your sink with the tab broken off. That gives you a dedicated outlet for each in a compact solution.
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Apr 8, 2021 04:49
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SpartanIvy posted:So for planning the rewiring of my house, I think I've got most of my circuits laid out like I want. The kitchen is currently planned to have 5 circuits. 2 dedicated countertop circuits, a dedicated microwave circuit, a dedicated refrigerator circuit, and a final circuit for the dishwasher, sink disposal, and the ventilation hood and light. I'm debating throwing the refrigerator on that last circuit too, so I'm open for opinions on that. Everything is going to be GFCI/AFCI breakers. I think in your situation a series of junction boxes in the crawlspace with a run up to each receptacle is an awesome idea, and easier and even a little cheaper. You should have your reefer on a dedicated circuit, it's hard to find but the code generally requires it based on branch circuit loading.
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Apr 8, 2021 06:44
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Elviscat posted:I think in your situation a series of junction boxes in the crawlspace with a run up to each receptacle is an awesome idea, and easier and even a little cheaper. Fridge and microwave is typical any more. Microwaves (and fridges) have come down a lot in nameplate current rating. edit: When I retrofitted my house, it was J-box per room in the crawlspace, with conductors going to each outlet. It's way, way easier to fish that way. If you're 100% rewiring, consider having one outlet per room that's on a different circuit; that way you can have a room shut off and still have power in it. I used a Sharpie to write the circuit number on the back of the faceplate; helps a TON when troubleshooting. babyeatingpsychopath fucked around with this message at 13:32 on Apr 8, 2021 |
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Apr 8, 2021 13:16
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If the dishwasher and disposal are rated for less than 16a total I think you can have them on the same 20a circuit (I can't per local code rules) or even split between the two required 20a small-appliance branch circuits (with restrictions for amp usage and local rules) but you're better off putting them on separate circuits like previously posted. Fridges can be on with one of the two required SABCs that serve the countertop (assuming it will use less than 80% of the 20a circuit and is not permanently installed) but I'd rather put it on it's own dedicated 15a circuit if there are only going to be the minimum two countertop circuits. 210.52(B)(1) and 210.23(A)(1). Microwaves still require a dedicated circuit.
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Apr 8, 2021 14:22
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My only issue with putting everything on its own circuit is my breaker slots. I have a 30 slot panel with 4 being taken up by a whole house surge protector and an interlocked generator breaker. Since basically everything is supposed to be GFCI and AFCI protected now tandem breakers aren't an option. Even being liberal with load calculations I don't exceed my 200 amp service so it's purely a breaker space issue. I'm already toying with the idea of a sub panel nippled off to the side as once I try to add an EV charger I'm out of space already.
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Apr 8, 2021 16:29
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babyeatingpsychopath posted:Microwaves have come down a lot in nameplate current rating. Say what? Maybe for small, low-wattage countertop models, but most over-the-range or built-in models at an actual usable size (>1.6 cuft) have been at around a 14A nameplate for years. There's a reason why this became a required dedicated circuit, because running almost any other kitchen appliance on a circuit with the micro will pop the breaker no problem. Another vote for a dedicated 15A or 20A for the fridge. Even big fridges are like 5A on the nameplate, but it's nice to not worry about something else tripping that breaker. Someone who isn't me also makes sure fridge and freezer circuits in his house have no GFCI/AFCIs on them. Not interested in losing hundreds of dollars in food over a failure in a 25 cent circuit board.
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Apr 8, 2021 17:49
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