#14 switch legs on 20A OCP

[Volta]

Volta, Convincing post, and at times I have wondered myself, however, the "point on the wiring system" is the outlet (or fixture) itself and, IMHO, the conductors to that point would be branch circuit conductors and 402.11 Uses Not Permitted.
Fixture wires shall not be used as branch-circuit conductors except as permitted elsewhere in the Code.

But, admittingly, thats MY point of view, but I think it is also supported by the fact that the conductors listed in 402 all have the "application provision" fixture wiring". Some additional Code clarification might be in order.

One common installation of an "outlet" located away from the "utilization" equipment is that required by
210.11 > 220.10 > 220.12 > 220.12(F) > 600.5(A) > "accessible location at each entrance to each tenant space for sign or outline-lighting use . . .".

So this is often located as a junction box in an attic, above a ACT ceiling, on a wall surface, etc. The sign contractor typically extends a FMLC whip or similar from the exterior sign to the interior outlet.

The sign is not the outlet, the 4-square in the attic is.

 

[SEO]

Do I have to use an antishort bushing?:grin:

Maybe an antifault bushing?:grin:

 

[Sierrasparky]

Boy this thread is still going! It's like the eveready bunny

 

[hurk27]

I'm going with my #1. It is common practice, that's the way we've always done it, and nobody calls anyone on it. --and for good measure, the switch is only rated for 15A so 20A can't get through.

And now we know the reason Chicago dont want you guys playing around with NM wiring methods:roll:

 

[Sierrasparky]

And now we know the reason Chicago dont want you guys playing around with NM wiring methods:roll:

Here Here

 

[Jim W in Tampa]

This is sad to see we have so many men out there that do something like this. I exspect it from a greeny but not electricians with a year under there belt. Makes me wonder what kind of inspectors we have that would not catch this. Inspectors should be more alert than to let this slide.

 

[M. D.]

....(240.5(B)(2)(2) for instance) allows up to 100 feet of 16 AWG to be tapped to the branch circuit.

So the NEC either allows these conductors, say, in a raceway (402.7) to extend from a "point on the wiring system at which current is taken to supply lighting equipment" (Art. 100 / Outlet) to a luminaire(s) some distance away, or they are talking about really big fixtures.:grin:

I would say the fixture wires may be extended up to 100' ,.. grocery store ,..think end to end fluorescent or those connected by a recognized raceway,. to the point of outlet

 

[hurk27]

I think stabbing codes here and there is just confusing.

The bottom line is the real reasons we should not do this.

first you must understand the difference between an over loaded conductor and fault current.

A conductor has to be able to carry the continuous current for it not to be over loaded, remember when the code allow higher current on a conductor, it is only for short periods of time, such as for motor starting and fault currents.

but if we install a circuit, it has to be protected from overloading for the long term.

This is specially true when it comes to receptacles, as we do not know what will be plugged into them,

would a single light socket ever over load a conductor feeding it, probably not, but if many are daisy chained from the same conductor it could, this is why conductors have to be protected at there continuous rating to the last "outlet box" because we cant control what gets connected after that, just like a receptacle.

I have seen where fixture whips burned up feeding rows of lights, because the EC had daisy chained to many fixtures from one fixture whip.

so why is under sized wires allowed? because I think UL intended for a fixture whip to only be used for one or two fixtures not ten, and a under sized conductor can handle its rated connected load for long term but will still clear a fault short term, but remember it will over heat when subject to higher current then it is rated, for long periods of time.

So in essences no where does the NEC allow conductors to be overloaded for long term, it allows conductors to handle short term currents that might far exceed there rated current, but this is for very short term.

 

[Volta]

I would say the fixture wires may be extended up to 100' ,.. grocery store ,..think end to end fluorescent or those connected by a recognized raceway,. to the point of outlet

Works for my intrepretation (240.4(E)) without having to define outlet by location.

This is sad to see we have so many men out there that do something like this. I exspect it from a greeny but not electricians with a year under there belt. Makes me wonder what kind of inspectors we have that would not catch this. Inspectors should be more alert than to let this slide.

Don't confuse my desire for a precise understanding of the exact logical determination of the rules set forth by my favorite book - with methods I would allow my employees to install - or do myself. The Code is the minimum, and I don't just reiterate that, I work that way.

We don't put #14 on 20 amp circuits in my company.

However, no one in this thread has demonstrated, to my satisfaction, with NEC Section progression(s), that it is necessarily non-compliant to install a #14 TFFN from a switch to a lighting fixture, tapped from a 20 (or 30!) (240.5(B)(2)(4)) amp circuit.

 

[hurk27]

We don't put #14 on 20 amp circuits in my company.

However, no one in this thread has demonstrated, to my satisfaction, with NEC Section progression(s), that it is necessarily non-compliant to install a #14 TFFN from a switch to a lighting fixture, tapped from a 20 (or 30!) (240.5(B)(2)(4)) amp circuit.

I can

A #14 TFFN is not listed in table 402.3 so 402.3 would not allow it to be used as a fixture wire.

and this is the whole of the story, fixture wire are special "high temp" conductors, that can operate at higher temperatures.

402.3 clearly states if it not in the table it is not a fixture wire, and cant be used as such.

402.3 Fixture wires shall be of a type listed in Table 402.3, and they shall comply with all requirements of that table.

The OP was talking about tapping regular THHN/THWN conductors so fixture wire is mute.

but even with using fixture wires that are in table 402.3 you are still limited to long term overload by table 402.5 which states #14 is only rated for 17 amps , and that is for the special high temp fixture wires, not chapter 3 conductors.

 

[Volta]

I can

A #14 TFFN is not listed in table 402.3 so 402.3 would not allow it to be used as a fixture wire.

Yes it is. Page 254 in 2008. Only up to a #16, I see now, but it is a fixture wire.

402.3 clearly states if it not in the table it is not a fixture wire, and cant be used as such.

I agree.

The OP was talking about tapping regular THHN/THWN conductors so fixture wire is mute.

That was not stated:

Posting this for the benefit of someone else - who has been doing this for 15 years....

Feeding #12 to branch lighting - then at the switching (particularly Grafik Eye's) changing to #14 and feeding it all with 20A OCP.

So is it allowed? If it is, or if it is not post the appropriate code sections allowing or dis-allowing it...

but even with using fixture wires that are in table 402.3 you are still limited to long term overload by table 402.5 which states #14 is only rated for 17 amps , and that is for the special high temp fixture wires, not chapter 3 conductors.

ok

 

[e57]

Remind me, what is the full list of topics again?

1. 14 AWG on a 20 amp OCPD.
2. :-? Branch circuit wiring....



True. But nothing requires that "outlet" to be the box the utilization equipment is mounted to. It can be some distance away. These fixture wires, in this instance, would be taps. A #14 fixture wire only has an allowable ampacity of 17 amps (T402.5).

Fixure wire is only a tap to single fixtures - I don't think I have ever seen fixure wire smaller than 12 on items that get daisy chained together, and even if there were - those items are listed and outside of premise wiring... Even if using fixtures as a raceway - the conductors would be sized by the branch conductors and 240.4 and in most cases (D).

Fixture wire is also an example where I have seem some severe damage to smaller conductors. #16 fixture wire will often blow open in fault conditions acting as a fuse before the OCP opens.

Back on the topic of premise wiring though - this is parts of the paper I found that bussman used to justify #18 and #16... for the 240.4(D) code changes to allow those sizes.

 

[hurk27]

Here Here

I was just joking with him when I made the comment:

And now we know the reason Chicago dont want you guys playing around with NM wiring methods:roll:

it was clear that he don't believe this from his post #3

That being said, I've known many who've made that sort of thing their standard practice, saying things like "fixture whips are sometimes only 16 AWG or 14 AWG," and "this is the way we've always done it." As if the switch is some sort of secondary CB that limits overcurrent to 15 amps.

All in fun

 

[iwire]

Fixure wire is only a tap to single fixtures -

Code reference?

 

[iMuse97]

And now we know the reason Chicago dont want you guys playing around with NM wiring methods:roll:

Wayne you GOTTA read the whole thread: that whole post about "My #1" was said in jest about another previous request for clarification on what exactly it was that people thought who supposed that any of this was permissible in the first place. For the record: I voted "not allowed."

 

[iMuse97]

And now we know the reason Chicago dont want you guys playing around with NM wiring methods:roll:

I've come to think of myself as quite a rope jockey these last few years.

 

[hurk27]

I've come to think of myself as quite a rope jockey these last few years.

Yea I know, I been hearing ya been sneaking over here in my neighborhood

Like I said look me up some time.

 

[e57]

Fixure wire is only a tap to single fixtures - I don't think I have ever seen fixure wire smaller than 12 on items that get daisy chained together, and even if there were - those items are listed and outside of premise wiring... Even if using fixtures as a raceway - the conductors would be sized by the branch conductors and 240.4 and in most cases (D).

In full context....

Code reference?

402.10, and 402.11

 

[iwire]

In full context....

402.10, and 402.11

Mark I do not see either of those sections prohibiting fixture wires from suppling more then one load.

 

[e57]

Mark I do not see either of those sections prohibiting fixture wires from suppling more then one load.

It doesn't, and in context - I did not say that was the case... You asked for a code ref' for a sentance out of context. (lookin' to pick a bone wit me... :roll

Anyway - 402.11 does not allow fixture wire as premise branch wiring... Where would you tap more on to it anyway????

For instance: Those plug in daisy chained drop-in fixtures - the plugs for them are #12 - and intended to carry a 20a circuit. But I can think of few fixures rated to feed thru to others that use conductors smaller than that. The few I can think of are UC lighting like Little Inch LINK. Both of which are listed systems of components. Would you tap into those for other fixtures?