House electric questions

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16,690
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NH
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Double tapping of breakers seems verboten, yet after looking at a breaker yesterday I noticed that it will easily take two wires. Why is that? Do some jurisdictions allow two wires on the breaker? [I found that when I popped the panel off; right after my home inspection the PO had a radon system installed, and yep, they ran a second wire to a breaker. I'm ignoring for now, but know that I should fix some day.] I put in some new outlets. Why is that they give you two sets of screws for hot and neutral, so you can daisy chain, but only one ground screw? I used up some of the fancy ground wire nuts I had (ok not fancy at all--it's just a nut with a hole in it) and then on the last one I remembered I had some Wago's that I'd rather use. I must have gotten the mid range outlets, despite having clamps for hot and neutral, the ground side was just a screw--maybe I just didn't pay enough. Labeling wires every so feet ought to be a law... as is installing a chaseway from basement to attic!
 
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4,102
Location
SW Ohio
The 2nd set of terminals are technically there so you can have a switched outlet (after breaking the tab). Outlets are not "splicing devices". Do people do it, including fully licensed electricians ? Yeap.
 
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16,690
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NH
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Originally Posted by kschachn
Two wires to a breaker is permitted as long as the breaker is listed for two: [Linked Image from i.stack.imgur.com]
Did not know that--I had read through a few home inspection articles and came across double tapping a number of times, but nothing about it being allowed.
Originally Posted by hallstevenson
The 2nd set of terminals are technically there so you can have a switched outlet (after breaking the tab). Outlets are not "splicing devices". Do people do it, including fully licensed electricians ? Yeap.
Hmm, interesting. Is that prohibited by code or by convention? I mean, both outlets are rated for full load (not simultaneously of course), thus that tie bar has to be rated for full load--so it seems like a natural splicing device.
 
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9,373
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Canuck living in California
For the most part, a 15A breaker will be wired pretty much to its capacity, so that is why it's not a good idea to double wire a breaker. From safety perspective there is no difference. The breaker will simply trip, that's its job. As for single ground, you are supposed pigtail the ground wires coming off of the cables, the outlet and then have one spare wire coming off of the pigtail connect to the ground on the box. [Linked Image]
 
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15,052
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Upper Midwest
Originally Posted by supton
Did not know that--I had read through a few home inspection articles and came across double tapping a number of times, but nothing about it being allowed.
Well local codes are free to be more restrictive than the NEC. But if the device is listed for that use then it is permitted unless otherwise prohibited. This type of connector is on a device that would not be listed for two (or three!) wires.The clamping force is not consistent on the wires: [Linked Image from brightsidehomeinspections.com]
 
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9,373
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Canuck living in California
Originally Posted by hallstevenson
The 2nd set of terminals are technically there so you can have a switched outlet (after breaking the tab). Outlets are not "splicing devices". Do people do it, including fully licensed electricians ? Yeap.
Makes no sense to me. If it were true you would need a separate cable and a separate breaker for each and every outlet.
 
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16,690
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NH
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Originally Posted by KrisZ
For the most part, a 15A breaker will be wired pretty much to its capacity, so that is why it's not a good idea to double wire a breaker. From safety perspective there is no difference. The breaker will simply trip, that's its job. As for single ground, you are supposed pigtail the ground wires coming off of the cables, the outlet and then have one spare wire coming off of the pigtail connect to the ground on the box. [Linked Image]
I don't get that drawing--a wirenut on ground makes sense, but then it uses one on neutral but not hot? Probably showing what is permissible I'm guessing. Most the boxes in my house are plastic, save a few in the basement that are metal--those all appear to be pigtailed as you indicate. I replaced a couple of worn outlets and I think they all used the outlet as a splice--been a couple months--but as a modular/manufactured I'd assume what was in the walls was done to code. Then again, I think all the outlets are on 20A breakers with 12/2 wiring and using 15A outlets. shrug I should go inventory it all again.
 
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4,102
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SW Ohio
Originally Posted by KrisZ
Originally Posted by hallstevenson
The 2nd set of terminals are technically there so you can have a switched outlet (after breaking the tab). Outlets are not "splicing devices". Do people do it, including fully licensed electricians ? Yeap.
Makes no sense to me. If it were true you would need a separate cable and a separate breaker for each and every outlet.
No, you use wire nuts or other proper splicing devices inside the box. The image you show shows exactly this but only with the neutral. You (can) do the same with the hot. [Linked Image from i.pinimg.com]
 
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519
Location
The Orca
Originally Posted by supton
Then again, I think all the outlets are on 20A breakers with 12/2 wiring and using 15A outlets. shrug I should go inventory it all again.
If there is only one socket on that 20A circuit, then it should be a 20A socket. If there are multiple sockets on that 20A circuit, then you can use 15A sockets. Aside from the fact that a single device that requires a 20A supply would have a 20A plug on it, which would not fit into a 15A socket. I was told that 15A sockets and 20A sockets are mechanically identical, other than the 20A socket allowing the T-shaped 20A plugs to be inserted whereas a 15A would not. I don't know if this is true, I am not an electrician .
 
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9,373
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Canuck living in California
Originally Posted by hallstevenson
Originally Posted by KrisZ
Originally Posted by hallstevenson
The 2nd set of terminals are technically there so you can have a switched outlet (after breaking the tab). Outlets are not "splicing devices". Do people do it, including fully licensed electricians ? Yeap.
Makes no sense to me. If it were true you would need a separate cable and a separate breaker for each and every outlet.
No, you use wire nuts or other proper splicing devices inside the box. The image you show shows exactly this but only with the neutral. You (can) do the same with the hot. [Linked Image from i.pinimg.com]
Ok, I see what you meant by splicing devices now. Thanks for clarifying.
 
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Messages
24,822
Location
Upstate NY
Most circuit breaker boxes are pretty full so adding more wires into it may not be a good idea. But if already there and not prohibited then I would leave alone.
 
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16,690
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NH
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Originally Posted by Donald
Most circuit breaker boxes are pretty full so adding more wires into it may not be a good idea. But if already there and not prohibited then I would leave alone.
I'll check the breaker but it does appear that I was wrong, this double tap is ok. I think they tapped the circuit for the bathroom lights, so it's not a big deal. I added two more circuits and still have about 4 open. Nevermind that I could open up 4 more as we took out the electric range and the electric dryer.
 
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16,690
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NH
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Originally Posted by zzyzzx
This is an easily solvable problem: [Linked Image from do-it-yourself-help.com]
? Not sure what your point is...? Plus I've stopped using nuts, Wago's are way easier to deal with.
 
Messages
24,822
Location
Upstate NY
Originally Posted by hallstevenson
Originally Posted by KrisZ
Originally Posted by hallstevenson
The 2nd set of terminals are technically there so you can have a switched outlet (after breaking the tab). Outlets are not "splicing devices". Do people do it, including fully licensed electricians ? Yeap.
Makes no sense to me. If it were true you would need a separate cable and a separate breaker for each and every outlet.
No, you use wire nuts or other proper splicing devices inside the box. The image you show shows exactly this but only with the neutral. You (can) do the same with the hot. [Linked Image from i.pinimg.com]
I have see where the electrician uses a single piece of wire looped around the screw for each outlet to power many outlets. From 2 to 4. You need to strip a little insulation in the right places. The issue many run into with pigtails is space in the box.
 
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8,951
Location
MA
Originally Posted by supton
Originally Posted by Donald
Most circuit breaker boxes are pretty full so adding more wires into it may not be a good idea. But if already there and not prohibited then I would leave alone.
I'll check the breaker but it does appear that I was wrong, this double tap is ok. I think they tapped the circuit for the bathroom lights, so it's not a big deal. I added two more circuits and still have about 4 open. Nevermind that I could open up 4 more as we took out the electric range and the electric dryer.
Unless the breaker allows extra wires, it's against code. If you have the room, just get another breaker. Basically the way I heard it is that UL only tests the breakers with one wire so the rating is only for one wire. Probably won't burn the house down if you don't. But even in my own panels, I've had loose wires with just one wire per breaker. You get flickering and hot outlets when the wires are loose. Much easier for them to be loose with 2 wires on it than one. Probably half the home inspections I've been on end up with a panel with a double tap, most of the time it's for something like a doorbell. Triple taps are rare and once in a while they find 14 gauge wire on a 20 amp breaker when it's supposed to be a 15 amp breaker.
 
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5,487
Location
Baltimore, Maryland, USA
Originally Posted by Donald
Most circuit breaker boxes are pretty full so adding more wires into it may not be a good idea. But if already there and not prohibited then I would leave alone.
Pretty much all electrical boxes, not just ones for the circuit breakers are undersized, IMO.
 
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