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How does a certified electrician make this mistake?

sorka

Well-Known Member
Feb 28, 2015
9,519
7,826
Merced, CA
I feel like a complete idiot not realizing this before since we've been blowing the 15 amp GFIC breaker since our Tesla install. So I looked at photos of the old panel and realized that they used to be 20 amp breakers but they're now 15 amp breakers on the distribution panel with 14 gauge romex. My first conclusion was that perhaps the house was built wrong and that they should never have had 20 amp breakers but then I did some reading and learned that GFIC outlets must be on a 20 amp breaker and since my GFIC plugs have 20 amp plug receptacles, I feel like an idot for now realizing this sooner.

So then I realized that those were extended loads. Next I climbed into the attic and removed the junction box cover and verified that those two loads were indeed 12 gauge but extended with 14 gauge.
The panel is even labeled GFIC on those breakers. The county inspector apparently completely missed it too.
 
I was under the impression that if any part of a circuit was 14 AWG you should only use a 15 Amp breaker because the breaker is to protect the wire.
IF a GFCI receptacle requires a 20 Amp breaker then the code would require 12 AWG. I have some GFCI receptacles on 15 Amp breakers and they work fine. I will do some research but nothing about how a GFCI receptacle works depends on loads. It is a simple device that measures current between the hot wire and neutral and detects a difference which would mean there is a Ground Fault.
 

sorka

Well-Known Member
Feb 28, 2015
9,519
7,826
Merced, CA
I was under the impression that if any part of a circuit was 14 AWG you should only use a 15 Amp breaker because the breaker is to protect the wire.
IF a GFCI receptacle requires a 20 Amp breaker then the code would require 12 AWG. I have some GFCI receptacles on 15 Amp breakers and they work fine. I will do some research but nothing about how a GFCI receptacle works depends on loads. It is a simple device that measures current between the hot wire and neutral and detects a difference which would mean there is a Ground Fault.

I guess the issue here is that I have 20 amp receptacles on a 12 gauge conductor that was converted at the load hookup to 14 gauge with 15 amp breakers. Pretty sure you can't have 20 amp receptacles with a 15 am breaker. It's not as bad as having 15 amp receptacles on a 20 amp breaker which would be a fire danger.
 
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qdeathstar

Completely Serious
May 17, 2019
4,397
4,567
VB
I feel like a complete idiot not realizing this before since we've been blowing the 15 amp GFIC breaker since our Tesla install. So I looked at photos of the old panel and realized that they used to be 20 amp breakers but they're now 15 amp breakers on the distribution panel with 14 gauge romex.

that is correct. You can only put 15 amp breakers on 14 gage wire.

My first conclusion was that perhaps the house was built wrong and that they should never have had 20 amp breakers but then I did some reading and learned that GFIC outlets must be on a 20 amp breaker
Nope...

.
So then I realized that those were extended loads. Next I climbed into the attic and removed the junction box cover and verified that those two loads were indeed 12 gauge but extended with 14 gauge.
The panel is even labeled GFIC on those breakers. The county inspector apparently completely missed it too.

Did the electrician extend the circuits are were they already like that?
 

qdeathstar

Completely Serious
May 17, 2019
4,397
4,567
VB
I guess the issue here is that I have 20 amp receptacles on a 12 gauge conductor that was converted at the load hookup to 14 gauge with 15 amp breakers. Pretty sure you can't have 20 amp receptacles with a 15 am breaker. It's not as bad as having 15 amp receptacles on a 20 amp breaker which would be a fire danger.

15 amp receptacles (which are 20 amp pass through) are not a fire hazard and that is pretty typical. Having a 20 amp receptacle on a 15 amp circuit is an issue though.
 

SMAlset

Well-Known Member
Mar 4, 2017
9,336
10,261
SF Bay Area
@sorka did you have a MPU or added panel that required rewiring during your install? Was this during the time that certain breakers were in short supply? I’m asking because in our install case 40A breakers were sold out all over (understand from covid manufacturing production issues and high demand from sudden boom in construction being allowed to start up plus all the solar installs happening in the SF Bay area). Believe 20A breakers were also hard to come by. We had photos of our original panel and asked them about it at the time of install. It was on their maintenance list to come back for when supply came in, which they did.
 

rjpjnk

Active Member
Mar 12, 2021
1,250
828
NJ
The most important thing is that the over-current protection (the breaker) matches the wire in the line it is feeding. If you have 14 gauge wire in any part of the circuit, that wire requires a 15 amp breaker. Therefore, a circuit with a combination of 12 and 14 gauge wire must have at most a 15 amp breaker.

The receptacle is important but much less of a factor. You can safely put a 15amp receptacle on a 20 amp circuit (i.e., 20 amp breaker with matching 12 gauge wire). But a 20 amp receptacle on a 15 amp circuit would be problematic because it would allow 20 amp plugs to be inserted which could trip the breaker.
 
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sorka

Well-Known Member
Feb 28, 2015
9,519
7,826
Merced, CA
@sorka did you have a MPU or added panel that required rewiring during your install? Was this during the time that certain breakers were in short supply? I’m asking because in our install case 40A breakers were sold out all over (understand from covid manufacturing production issues and high demand from sudden boom in construction being allowed to start up plus all the solar installs happening in the SF Bay area). Believe 20A breakers were also hard to come by. We had photos of our original panel and asked them about it at the time of install. It was on their maintenance list to come back for when supply came in, which they did.

Yes, all new panel. But at the very least they could have extended the conductor with the same sized conductor which would make it a trivial matter to put the 20 amp breakers in when they were available. Now there are 20 amp breakers. I had 9 before the panel change vs 7 now.
 

arnolddeleon

Active Member
Supporting Member
Jul 21, 2012
1,020
1,098
SF Bay Area
I guess the issue here is that I have 20 amp receptacles on a 12 gauge conductor that was converted at the load hookup to 14 gauge with 15 amp breakers. Pretty sure you can't have 20 amp receptacles with a 15 am breaker. It's not as bad as having 15 amp receptacles on a 20 amp breaker which would be a fire danger.
Actually this is a specific exception that is allowed. Unless you use a cheater cord the only thing you can plug in 15A receptacle is a 15A load.
 

sorka

Well-Known Member
Feb 28, 2015
9,519
7,826
Merced, CA
So did the electrician extend the 12 gauge circuits with 14 gauge wire at the same time he downgraded the breakers from 20 to 15 amps?

Why was the thinner wire used?

Yes, the 12 gauge was extended 5 feet with 14 gauge. Why? Your guess is as good as mine. But it's not the first issue. The first issue is the day that is was finished, one of my circuits wasn't working. He insisted that it wasn't an issue at the panel that my house wiring must be defective. I pulled every switch out of their boxes and traced everything only to find that the missing power was because the wire wasn't hooked up to any circuit. It was hiding under one of the larger conductors.
20201017_133309.jpg
 

sorka

Well-Known Member
Feb 28, 2015
9,519
7,826
Merced, CA
15 amp receptacles (which are 20 amp pass through) are not a fire hazard and that is pretty typical. Having a 20 amp receptacle on a 15 amp circuit is an issue though.

It would be if it were 14 gauge wire which part of it is now. And I'll state it again since it seems to be missed. The GFCI circuits that used to be 20 amps STILL all have 20 amp receptacles AND plugs.

20210428_221253.jpg
 

rjpjnk

Active Member
Mar 12, 2021
1,250
828
NJ
Yes, the 12 gauge was extended 5 feet with 14 gauge. Why? Your guess is as good as mine.
Wow, that totally stinks! Was this recent work? I would call them ASAP if so and explain that you didn't agree to downrate the circuits to 15 amps.
I doubt it was a mistake because the fact that he replaced the 20 amp breakers with 15 amp indicates that he was aware that his use of smaller gauge wire in the extension would require lower current breakers. As least he didn't leave you with 20 amp breakers feeding the 14 gauge wire, which would have been a fire hazard. I'd ask him to replace the added wire with 12 gauge and restore your circuits to their former rating.
 

sorka

Well-Known Member
Feb 28, 2015
9,519
7,826
Merced, CA

And a hundred other sources so I'm sure it's there in the NEC requirements as well.
 
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rjpjnk

Active Member
Mar 12, 2021
1,250
828
NJ
... And I'll state it again since it seems to be missed. The GFCI circuits that used to be 20 amps STILL all have 20 amp receptacles AND plugs.

View attachment 657910
Yeah, I understand. That's bad too, but for different reasons. If you don't swap the wire back to 12 gauge I would replace these with 15 amp receptacles to match your gimped circuits. Problem is, many places were GFCIs are required are also places where 20 amp service is required, like bathrooms and kitchens. Better off fixing the wire problem.

I am shocked to hear that it was a Tesla contractor that did the work. I hope they fix it for you without issue.
 

sorka

Well-Known Member
Feb 28, 2015
9,519
7,826
Merced, CA
Yeah, I understand. That's bad too, but for different reasons. If you don't swap the wire back to 12 gauge I would replace these with 15 amp receptacles to match your gimped circuits. Problem is, many places were GFCIs are required are also places where 20 amp service is required, like bathrooms and kitchens. Better off fixing the wire problem.

I am shocked to hear that it was a Tesla contractor that did the work. I hope they fix it for you without issue.

They are required as I mentioned in the first post.
 

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