Breaker size vs wire size

[Russell_Reid]

Our outbuilding passed the city final inspection this week. So we will be closing out the contractors scope of work and moving to ours. During one of my walk throughs I noticed something about the breakers that seemed odd. My electrician did great work. Very clean and he was responsive and helpful. Even with the change orders (very few).
I documented the wire runs after rough in before drywall. He ran the circuits using 12 ga for the receptacle distribution, 12 ga for the feed line to the lighting circuits and 14 ga for the distribution lines to the lighting fixtures. I have no problems with that.
But he used 20 amp breakers for everything. So the lighting circuits (14 ga, LED cans, LED wall sconces) are all using 20 amp breakers. Granted the load will never get close to 20 amps on these circuits. But I was surprised that he used 20 amp for the lighting instead of 15 amp.
I looked it up in the NEC copy that I have but didn't really understand if this is allowed or not.
Is this an allowed condition or should I replace the 20 amp lighting circuit breakers with 15 amp?

 

[theoldwizard1]

... 12 ga for the feed line to the lighting circuits and 14 ga for the distribution lines to the lighting fixtures.

I don't understand. In the middle of a run, he changed from 12/2 to 14/2 ? Odd. That circuit should use a 15A breaker.

 

[u2slow]

Code or not, a dedicated lighting circuit (no receptacles) can only draw what the downstream fixtures demand. A 15 or 20A breaker will trip on a short-circuit just the same. I wouldn't lose sleep over it. Or change to 15's if it bothers you greatly.

 

[Russell_Reid]

I will have to go through my photos to confirm where the change takes place, but i know for a fact that there is 14 ga romex run to the lighting fixtures (white jacket) and everything in the panel is 12 ga romex (yellow jacket). And all breakers in the panel are 20 amp. Its a 100 amp sub panel. It passed both rough in and final inspection. But we have one very overloaded city inspector who does both permit review and all inspections. So I dont know how thorough his inspection was.

 

[mike93lx]

It's not allowed. Any circuit with 14 gauge nm-b in it should be on a 15a breaker.

Its really too bad the lighting wasn't kept separate. Losing your lights when something high draw pops a breaker is not fun, especially when that is something like a table saw.

Hopefully the lights are not also on the gfci protection that I am assuming you have as well...

If the walls are open, I'd be looking at moving the lighting over to dedicated breakers

 

[Russell_Reid]

Code or not, a dedicated lighting circuit (no receptacles) can only draw what the downstream fixtures demand. A 15 or 20A breaker will trip on a short-circuit just the same. I wouldn't lose sleep over it. Or change to 15's if it bothers you greatly.

It doesn't 'bother' me per se. I know the lighting isn't close to overloading and a short will trip regardless. Just my paranoid brain was wondering if there is any condition that could cause a high enough draw on the 14 ga wires to cause damage without tripping the 20 amp breaker. The LED recessed cans have a control box (they are dimmable and have switchable color temp, no dimmers installed currently) and the bathroom fan is on the same circuit with the lighting in the bathroom.

 

[Russell_Reid]

It's not allowed. Any circuit with 14 gauge nm-b in it should be on a 15a breaker.

Its really too bad the lighting wasn't kept separate. Losing your lights when something high draw pops a breaker is not fun, especially when that is something like a table saw.

Hopefully the lights are not also on the gfci protection that I am assuming you have as well...

If the walls are open, I'd be looking at moving the lighting over to dedicated breakers

The lighting circuits are separate from the receptacle circuits. So tripping a breaker with a plugged in item will not trip out the lighting. Lighting in the office/bathroom is a separate circuit from the lighting in the shop. Same with receptacles. He and I went over the circuiting when he was roughing in to ensure a good separation of circuiting to prevent the condition you describe. Yes there is GFCI protection where it belongs.

 

[mike93lx]

The lighting circuits are separate from the receptacle circuits. So tripping a breaker with a plugged in item will not trip out the lighting. Lighting in the office/bathroom is a separate circuit from the lighting in the shop. Same with receptacles. He and I went over the circuiting when he was roughing in to ensure a good separation of circuiting to prevent the condition you describe. Yes there is GFCI protection where it belongs.

My bad, I see they are separate.

I'd just swap the 20's for 15's on the lighting and be done

 

[sparky 1971]

There are a few instances where #14 wire would be allowed to be on a 20 amp breaker (motors and air conditioners) but lighting usually isn't one of them and isn't in this case. Since this is blatantly obvious, I'm going to go out on a limb and say that the city inspector is one of those guys that comes out and looks at everything at once, but doesn't know much about anything. I'm also gonna say the electrician doesn't know much either even if he does nice work; anyone can run romex in a straight line and make it look nice. Personally, if it were my shop I wouldn't lose any sleep over it. It would be one of those things that I'd plan on getting to one of these days and probably never would get it done.

The easiest code reference you will find is going to be table 310.16 and check out the * next to 14. BTW, romex is sized using the 60° but doesn't matter in this case.

 

[PopcornSutton]

Some light fixtures are a pain to wire, the boxes are flimsy and small. 14 gauge sure makes it easier and neater. With so much LED in use now, you would be hard pressed to overload the circuit.

 

[PCustoms]

Some light fixtures are a pain to wire, the boxes are flimsy and small. 14 gauge sure makes it easier and neater. With so much LED in use now, you would be hard pressed to overload the circuit.

???

14awg on a 20A breaker is not allowed for this type of circuit

 

[mm08822]

Permit plans usually have a construction office copy and a field copy. Too many times, I have been told by customers that the inspector came onto the job site and asked what he was inspecting. This means IMO, he never looked at the job plan either last night or this morning before making the rounds.

Chances are good that the inspector saw yellow colored nm-b (no white present) entering the panel and therefor 20a cb's seems logical for general purpose recepts and lighting.

I have found this to be a trap when doing a service replacement and you are relying on the existing cb's rating for the replacement cb rating.

Call the electrician back and have him change them. Have him open the box where the transition from 12 to 14 was made (per your notes) and let him try and splain it away using a code reference.

 

[mm08822]

???

14awg on a 20A breaker is not allowed for this type of circuit

There are a few exceptions for lighting but it is something like 18 or 24" max. None of which involves permanent building wiring, IIRC.

 

[mike93lx]

Chances are good that the inspector saw yellow colored nm-b (no white present) entering the panel and therefor 20a cb's seems logical for general purpose recepts and lighting.

I think this is why my house has #10 for the hvac circuits (25a breaker) that runs to a junction box in the crawl to transition to #12 for the rest of the run. I bet the sparky just didn't want the potential problem with an inspector

 

[sparky 1971]

There are a few exceptions for lighting but it is something like 18 or 24" max. None of which involves permanent building wiring, IIRC.

That's one that I'm not familiar with and don't care enough to look it up. I was thinking about commercial lighting using the #16 or #18 whips for individual fixtures.

 

[mm08822]

I think this is why my house has #10 for the hvac circuits (25a breaker) that runs to a junction box in the crawl to transition to #12 for the rest of the run. I bet the sparky just didn't want the potential problem with an inspector

Or he ran out of 10 and before he got back to finishing, the compressor landed and 12 was fine. As long as the MCA was met it doesn't matter and the inspector wouldn't have been able to argue it.

 

[MovingAlong]

... or should I replace the 20 amp lighting circuit breakers with 15 amp?

I would replace them.

It's not the load from a properly functioning light, it's the overload from a failed light. Or a squirrel, staple, or nail hanging a picture. You'll want the breaker to trip before the 14 gauge acts as a fuse... and the 20 amp probably would trip with a dead short, but now you're making an assumption of how it will fail. Better to size all the components of the system correctly.

 

[mm08822]

That's one that I'm not familiar with and don't care enough to look it up. I was thinking about commercial lighting using the #16 or #18 whips for individual fixtures.

Nor I, not something any of my jobs types today include and seems like just more materials to manage and run out of at the last minute.

 

[mike93lx]

Or he ran out of 10 and before he got back to finishing, the compressor landed and 12 was fine. As long as the MCA was met it doesn't matter and the inspector wouldn't have been able to argue it.

Anything is possible.

The inspector would have lost, yes, but it's still time.

 

[micromind]

That's one that I'm not familiar with and don't care enough to look it up. I was thinking about commercial lighting using the #16 or #18 whips for individual fixtures.

Reloc come to mind.

Popular in the 90s around here, a lot of it has been replaced though.

 

[sparky 1971]

I think this is why my house has #10 for the hvac circuits (25a breaker) that runs to a junction box in the crawl to transition to #12 for the rest of the run. I bet the sparky just didn't want the potential problem with an inspector

He was probably there before the HVAC contractor, knew the approximate location of the units, and pulled the #10 close enough. Then found out he only needed a #12 after the fact. That's one of the reasons that, even though I only wire a house about every other code cycle (which is just enough to remind myself why I don't wire new houses), I won't do anything other than the service before the plumber and AC man are finished with their rough in.

 

[mike93lx]

He was probably there before the HVAC contractor, knew the approximate location of the units, and pulled the #10 close enough. Then found out he only needed a #12 after the fact. That's one of the reasons that, even though I only wire a house about every other code cycle (which is just enough to remind myself why I don't wire new houses), I won't do anything other than the service before the plumber and AC man are finished with their rough in.

The junction box is pretty close to the panels and nowhere near the condensors.

Anything is possible... But speculation is fun

 

[Russell_Reid]

OK, just did a quick dig back through my pics during rough in. It looks like the 12 ga power to the lighting circuits runs to the head switch location. Then it is 14 ga from the switch out to the lighting fixtures. I will have to pull the panel cover to see how all the wires tie in to breakers. I didnt get a picture of that prior to closing the panel for final. I will put replacing those breakers on my to-do list. Just for reference the electrician was the contractor I had the least complaints about. Aside from how he would only work until noon. But we were hitting 100 every day so I can't really blame him.

 

[mm08822]

The junction box is pretty close to the panels and nowhere near the condensors.

Anything is possible... But speculation is fun

Maybe just trying to get out of the wall for insulation/drywall.

Or....

Or....

Or...

 

[mike93lx]

Maybe just trying to get out of the wall for insulation/drywall.

Or....

Or....

Or...

The possibilities are endless!

 

[mm08822]

Call him

 

[wyliesdiesels]

Is this an allowed condition or should I replace the 20 amp lighting circuit breakers with 15 amp?

Definitely not allowed

This guy doesnt know the basics of wire amapacity…

He should be the one fixing it…

 

[wyliesdiesels]

I will have to go through my photos to confirm where the change takes place, but i know for a fact that there is 14 ga romex run to the lighting fixtures (white jacket) and everything in the panel is 12 ga romex (yellow jacket). And all breakers in the panel are 20 amp. Its a 100 amp sub panel. It passed both rough in and final inspection. But we have one very overloaded city inspector who does both permit review and all inspections. So I dont know how thorough his inspection was.

Not thorough enough

 

[Dagny]

I wire few homes for builders. Mainly because I don't want to wire one to minimum code. I tell people I'll wire your house like I would wire it if if it was my own.

Most of the homes I wire are when a dairy farmer retires and sells the farm and keeps 5 acres to build a new house on.

I have done many $$$ of work on their farm in some pretty crappy conditions. You don't know what cold is till you climbed a 70 foot silo when it's 20 below.

When done with a silo or manure pump I would me up with the farmer in the milk house with my thermos to have a cup and wash the poop off me or get the haylage outa my hoodie they would be very grateful and would most often prove it by hiring me to do the clean jobs also.

When wire insulation is evaluated they are buried in insulation and tested for years. I have ran whole farms on ten gauge wires after tornadoes dairy cows have to be milked on time or they get all kinds of health problems. I learned a lot during these emergency wiring jobs a 14 ga. wire on a 20 amp breaker is wrong but will never cause any trouble.

 

[vavet]

OK, just did a quick dig back through my pics during rough in. It looks like the 12 ga power to the lighting circuits runs to the head switch location. Then it is 14 ga from the switch out to the lighting fixtures. I will have to pull the panel cover to see how all the wires tie in to breakers. I didnt get a picture of that prior to closing the panel for final. I will put replacing those breakers on my to-do list. Just for reference the electrician was the contractor I had the least complaints about. Aside from how he would only work until noon. But we were hitting 100 every day so I can't really blame him.

At least it’s not a hidden splice somewhere...so there’s that.