12 gauge to the room, 14 for lights and 3-way

[tallguy]

I'm just curious what you guys would do if you encountered this kind of installation. Would you change the breaker to a 15 (assuming it's a 20) or just look past it?

I would (and do) switch them to 15's if I see any hint of 14ga. wire on the circuit. Simply put:

1) I have no clue where else there may be 14ga. wire in the circuit
2) I'm not about to try to rationalize whether or not it is "safe"
3) It's non-conforming
4) Cheap fix

 

[480sparky]

Whenever I do a rewire, I always use some of the existing circuits. I always put the old general-purpose circuits on 15amp breakers whether they're 14 or 12, since I don't know if somewhere along the line did exactly this type of install. I have never had to go back because the 15amp breaker is tripping.

 

[tallguy]

Whenever I do a rewire, I always use some of the existing circuits. I always put the old general-purpose circuits on 15amp breakers whether they're 14 or 12, since I don't know if somewhere along the line did exactly this type of install. I have never had to go back because the 15amp breaker is tripping.

I've been wrestling with this one a bit as I keep on finding bits and pieces of circuits in my current project w/ #14 wire. I've been replacing CB's piecemeal, but feel as though I should just yank all of the 20's out since I can't know what is on each circuit without popping open every single j-box, receptacle and switch in the place....

 

[M. D.]

That's a good question, I could guess at an answer. Keeping #14 at 15 amps insures that Joe DYI'er has some fudge room for his violations. Before you ask, I have absolutely no documentation to prove this.

I sometimes I use statement when customers ask why ,... why,... but why,....

90.1(a) The purpose of the NEC ?is the practical safeguarding of persons and property from hazards arising from the use of electricity?

I never like to say ,"I don't know"

Yes , I would change the circuit breaker to the correct size and do whenever I see it.

 

[bkludecke]

I've been wrestling with this one a bit as I keep on finding bits and pieces of circuits in my current project w/ #14 wire. I've been replacing CB's piecemeal, but feel as though I should just yank all of the 20's out since I can't know what is on each circuit without popping open every single j-box, receptacle and switch in the place....

We routinely r&r w/15amp CBs. The chances of tripping a breaker are slim unless it is an appliance circuit.

 

[radiopet]

I would personally replace the 20A OCPD with a 15A OCPD and be done with it. The weakest link ( without the exceptions to the rule ) would be the best choice in this case. Since the NEC tells us the ampacity of the NMC based on 60 degree's as I believe I-Wire stated.....as well as the following:

(D) Small Conductors. Unless specifically permitted in
240.4(E) or 240.4(G), the overcurrent protection shall not
exceed 15 amperes for 14 AWG, 20 amperes for 12 AWG,
and 30 amperes for 10 AWG copper; or 15 amperes for
12 AWG and 25 amperes for 10 AWG aluminum and
copper-clad aluminum after any correction factors for
ambient temperature and number of conductors have
been applied.

I guess unsafe brings in the fact of yes it is 14AWG,,,and if you use 310.16 we can see the actual ampacity of the 14 AWG....but alas we know we can only use the 60 degree column....unsafe...well the properly sized OCPD will make it SAFER than it would be so thats of optimum word i guess.

The majority of times we run conduits to " the other execptions " allowed and are able to use the total ampacity for adjustment and what have you.

P.S. Just broke my femur last week and just now getting to my computer again.....feeling loopy so hope this types out ok...

 

[winnie]

And if 20 amps is safe on branch circuits of #14 then why did they make the rule to use a 15 ?

I don't remember where I read this, so I can't point out a confirming reference. But I recall reading somewhere that the 'small conductor' requirements for OCPD are related to short term (eg short circuit) protection, rather then long term (overload) protection.

My guess is that if you overlay the 'conductor damage curve' with the 'OCPD trip curve' that smaller conductors have more regions where the conductors get damaged before the OCPD trips.

Thinking about this more, the _time_ response to an overload is relatively more rapid in smaller conductors than in larger conductors. Take a look at the thermal ampacities given in table 310.16, and calculate the 'circular mils per amp' value for different conductors. You will find that larger conductors have more 'circular mils per amp'. In an sudden overload or short circuit, those circular mils per amp represent thermal mass that slows any temperature rise.

-Jon

 

[iwire]

II guess unsafe brings in the fact of yes it is 14AWG,,,and if you use 310.16 we can see the actual ampacity of the 14 AWG....but alas we know we can only use the 60 degree column....

Paul the 60 C rating of 14 AWG is in fact 20 amps.

Yes of course I will follow the code but as in other areas of the NEC I can run 20 amps on 14 AWG I will not be convinced that 14 AWG on a 20 amp circuit is 'unsafe', violation yes, unsafe no.

 

[iwire]

But I recall reading somewhere that the 'small conductor' requirements for OCPD are related to short term (eg short circuit) protection, rather then long term (overload) protection.

Jon, I am not so sure.

If I use 14 AWG to supply a motor the short circuit protection could potentially be a 50 or 60 amp breaker.

 

[andinator]

Paul the 60 C rating of 14 AWG is in fact 20 amps.

Yes of course I will follow the code but as in other areas of the NEC I can run 20 amps on 14 AWG I will not be convinced that 14 AWG on a 20 amp circuit is 'unsafe', violation yes, unsafe no.

I also always change the OCPD from 20 to fifteen when I find fourteen AWG but i'm also sticking to my guns...not code but not unsafe.

 

[electricmanscott]

When I do a service change I put the #12 on 20 amp if that's what they were on.

As for the original topic it always amazes me when this comes up. Why people think it is allowed is beyond me. As far as the NEC goes this is about as basic as you can get. Kind of scary if you ask me.

 

[stickboy1375]

When I do a service change I put the #12 on 20 amp if that's what they were on.

As for the original topic it always amazes me when this comes up. Why people think it is allowed is beyond me. As far as the NEC goes this is about as basic as you can get. Kind of scary if you ask me.

Even more amazing when you see it done...

 

[tallguy]

Even more amazing when you see it done...

What boggles my mind is that a service change can be done and whatever is on #12 gets a 20A CB, without any thought that the circuit isn't necessarily #12 all the way. I dunno though... when you're dealing with properties that started out K&T and have been worked and reworked over nearly 100 years, it's very hard to sort out what went wrong when.

 

[Mister Kool]

if 20 amps is safe on branch circuits of #14 then why did they make the rule to use a 15 ?

if you could use #14 for 20amps then no one could sell #12 wire...lol...lol.
its about the money...lol

 

[electricmanscott]

What boggles my mind is that a service change can be done and whatever is on #12 gets a 20A CB, without any thought that the circuit isn't necessarily #12 all the way. .

# 10 in the panel, who knows what happens when the circuit goes behind walls. 15 amp for that too? What if something feeds a bathroom or kitchen receptacle? Do you just install GFCI breakers for all circuits?

Where is the line drawn?

 

[tallguy]

# 10 in the panel, who knows what happens when the circuit goes behind walls. 15 amp for that too? What if something feeds a bathroom or kitchen receptacle? Do you just install GFCI breakers for all circuits?

Where is the line drawn?

For me, it's generally when I observe #14 in the circuit myself.

What's frustrating is that somewhere along the way someone either put the #14 in there deliberately (as in a scenario described by the OP) or upgraded the circuit without knowing what was what. If the circuit was 15A prior to service change, it should remain so afterwards -- without regard to what is landed on the CB (assuming it's not #16 :grin. Just my opinion.

 

[dnem]

For me, it's generally when I observe #14 in the circuit myself.

That's reasonable. . When you come into an existing building, the assumption is that the existing stuff is compliant.

The problem is how to handle a significant violation that isn't a quick and cheap fix and the owner refuses to pay for the fix. . But if you find that your scope makes you interact with a violation, you'll have to either fix the violation or find another way to get your job done while staying clear of the screwed up preexisting work.

David

 

[M. D.]

..... . But if you find that your scope makes you interact with a violation, you'll have to either fix the violation or find another way to get your job done while staying clear of the screwed up preexisting work.

David

In Mass this is expressed in rule #3 .My question is How do we add without increasing the magnitude:-?

Rule 3. Additions or modifications to an existing installation shall be made in accordance with this Code without bringing the remaining part of the installation into compliance with the requirements of this Code. The installation shall not create a violation of this Code, nor shall it increase the magnitude of an existing violation.

 

[radiopet]

Paul the 60 C rating of 14 AWG is in fact 20 amps.

Yes of course I will follow the code but as in other areas of the NEC I can run 20 amps on 14 AWG I will not be convinced that 14 AWG on a 20 amp circuit is 'unsafe', violation yes, unsafe no.

I understand that Bob....and I agree 100% in the 20A on 14 AWG based on 60 C ratings.....was more so refering to the requirements of 240.4(D)..but in the end I agree while a violation...not so much a safety concern I guess unless of course someone forgets it is romex and needs to use the 60 C Column anyway.

 

[cschmid]

The situation that fun wiring has brought up when I owned my contracting business we seen allot of this and inspection stickers still present. its not broke no fix leave it alone unless inspector cities it than home owner forced to do something and it not you fault... reason for not contracting ask my ex-wife and it is allot less stressful now... Bob is very knowledgeable on the code...We even got called to this job the HO was doing and sold house in middle of project, seems he went through and cut off the unused conductors in the nm to make three way circuits instead of using 3 wire cable...so is that legal? and no there was no pass sticker on this job we removed and installed 3 wire to three way switches...customer very happy and so was inspector...I constantly find circuits with high rated circuit breakers in them and fuses too... if it is blowing the protection don't fix the problem just up the protection, must be owner thing...