#14 switch legs on 20A OCP

[480sparky]

Sure you can choose to find something in 240.4(E) or (G) to get out of (D) - but what in those codes listed in each (E) or (G) "Specifically Permits" the contradiction of allowing higher amperages on smaller conductors that would otherwise be limited. Without a "specific" perimission IMO you are stuck with 240.4(D) on small conductors #10 or smaller.

Can anyone point to any language in any of the codes listed in (E) or (G) that says '240.4(D) shall not apply'? That would be "specific"...

OK, let's print it out:

(D) Small Conductors. Unless specifically permitted in 240.4(E) or (G), the overcurrent protection shall not exceed that required by (D)(1) through (D)(7) after any correction factors for ambient temperature and number of conductors have been applied.

Hightlighted in blue: If my installation falls under (E), (F), or (G), then I use the appropriate section that applies. Otherwise, I'm stuck with the small conductor rule of (D)(1)-(7).


240.4(D) starts out with references to (E), (F) & (G). It says that if your installation is a tap, a transformer secondary, or anything specifically listed in (G), YOU USE THAT SECTION. If your installation DOES NOT fall under (E), (F) or (G), then it says to use (D)(1) through (7).

 

[RB1]

What if I considered the switch leg a Class I nonpower limited circuit? It is used for the remote control of the luminaire. There are lighting systems on the market that use the Class III designation between the luminaire fittings.

 

[mivey]

OK, let's print it out:



Hightlighted in blue: If my installation falls under (E), (F), or (G), then I use the appropriate section that applies. Otherwise, I'm stuck with the small conductor rule of (D)(1)-(7).


240.4(D) starts out with references to (E), (F) & (G). It says that if your installation is a tap, a transformer secondary, or anything specifically listed in (G), YOU USE THAT SECTION. If your installation DOES NOT fall under (E), (F) or (G), then it says to use (D)(1) through (7).

Why do you keep including (F) when it only says (E) OR (G) ?

 

[augie47]

I DID NOT vote that it was allowed, but there was a time a few years back when the regional supervisor for TN State inspectors confirmed a State policy (unwritten) that #14 could be used on a 20 amp circuit as a "switch leg" for a light fixture as long as no neutral was in the cable (thus only cables from the light down to a switch). The few inspectors that I know that accepted this, discontinued the practice on his retirement.

(the primary difference in our organization and the Boy Scouts is that the Boy Scouts have adult leadership)

 

[mivey]

I DID NOT vote that it was allowed, but there was a time a few years back when the regional supervisor for TN State inspectors confirmed a State policy (unwritten) that #14 could be used on a 20 amp circuit as a "switch leg" for a light fixture as long as no neutral was in the cable (thus only cables from the light down to a switch). The few inspectors that I know that accepted this, discontinued the practice on his retirement.

When I was learning, some inspectors would allow #14 switch legs on 20 amp circuits and we would run across them from time to time. We never bought into that practice, and I'm glad I was taught better.

 

[MarkyMarkNC]

OK, I actually misread the question when I voted and thought it was for fixture whips instead of switch legs when I voted yes. Technically I believe the correct answer is NO, and I have never installed a switch LEG with # 14.

But.......for all the freak out, "oh my God, you hacks are going to burn the place to the ground" crowd in this thread, I have to ask, how is a #14 switch leg with 20A OC any more dangerous than a #14 fixture whip or fixture wire on 20A OC?

 

[mivey]

OK, I actually misread the question when I voted and thought it was for fixture whips instead of switch legs when I voted yes. Technically I believe the correct answer is NO, and I have never installed a switch LEG with # 14.

But.......for all the freak out, "oh my God, you hacks are going to burn the place to the ground" crowd in this thread, I have to ask, how is a #14 switch leg with 20A OC any more dangerous than a #14 fixture whip or fixture wire on 20A OC?

Because you can burn the place to the ground, of course. :grin:


add: NFPA = National Fire Protection Association

 

[iMuse97]

OK, I actually misread the question when I voted and thought it was for fixture whips instead of switch legs when I voted yes. Technically I believe the correct answer is NO, and I have never installed a switch LEG with # 14.

But.......for all the freak out, "oh my God, you hacks are going to burn the place to the ground" crowd in this thread, I have to ask, how is a #14 switch leg with 20A OC any more dangerous than a #14 fixture whip or fixture wire on 20A OC?

A fixture whip typically "sees" one fixture, while a switch leg sees the whole load.

 

[celtic]

...all this talk of whips and switches......some of you guys need anger management

 

[mcclary's electrical]

A fixture whip typically "sees" one fixture, while a switch leg sees the whole load.

I agree.......

 

[Sierrasparky]

I second!:grin:

 

[RB1]

I agree that is not permitted but I thought the 725 angle would be an interesting angle. This has been cussed and discussed in Tennessee for years.

 

[hurk27]

Sure you can choose to find something in 240.4(E) or (G) to get out of (D) - but what in those codes listed in each (E) or (G) "Specifically Permits" the contradiction of allowing higher amperages on smaller conductors that would otherwise be limited. Without a "specific" perimission IMO you are stuck with 240.4(D) on small conductors #10 or smaller.

Can anyone point to any language in any of the codes listed in (E) or (G) that says '240.4(D) shall not apply'? That would be "specific"...

You are correct, the NEC does not allow a higher amprage load on a wire of a given size! nor does it allow a conductor to ever be over loaded.

And the alowance in 240.4(G) doesent either.

What it does allow is for us to use the alowance in 430 that will allow a # 14 to feed a 12 amp load that has its own overcurrrent protection device in it, such as a condenser compressor motor, and allow a much higher breaker to overcome the startup current, then your just protecting for fault current, remember fault current will be many times higher than the rating of any wire, as much as 1500 amps, but it will clear a breaker way before any damage to the little #14 wire can occur.

remember the conductor is protected from overload by the overcurrent device in the compressor, and since it would be very unliklly someone would ever change it to a higher rating, or add more loads on to it.

This is why it is allowed

 

[hurk27]

Also keep in mind that a #14 can withstand 97.31 amps for 5 seconds before it starts to damage the insulation, much longer than it will take to clear a breaker on a fault.

 

[Sierrasparky]

Also keep in mind that a #14 can withstand 97.31 amps for 5 seconds before it starts to damage the insulation, much longer than it will take to clear a breaker on a fault.

Thanks did not know that!

did you know what makes NM bad tasting to Varmits. ?????

 

[hurk27]

Thanks did not know that!

did you know what makes NM bad tasting to Varmits. ?????

No problem, I got it from a link Don posted in another thread on ground Fault current. very interesting stuff

Heres the Link to the PDF

 

[Jim W in Tampa]

Also keep in mind that a #14 can withstand 97.31 amps for 5 seconds before it starts to damage the insulation, much longer than it will take to clear a breaker on a fault.

yes but what does that have to do with an unknown load ? Problem here is you allow the #14 because you see 5 light fixtures NOW. 5 months from now they add 20 more and the electrician looks at breaker size and ballast amps. He will never know about the cheap a-- that used #14 to save $1. He will more times than not even check amps now. I have many times added 1 or 2 more at 277 without asking or checking in factories because it would easily take an extra hour and 1 more man and shut down operations. I must rely on past electrician to not do something as stupid as under size a switch leg. that looks looks like a #12 circuit. I would checks amps at breaker and if close to 16 will walk away. Only hacks do garbage work like changing to #14. If your one of them please don't let me ever know. When we walk in on remodels we MUST assume what is there is correct and safe and only deal with what we add. If your one of them please then please find some job your qualified for , perhaps a garbage truck. Your messing with lves.

 

[hurk27]

yes but what does that have to do with an unknown load ? Problem here is you allow the #14 because you see 5 light fixtures NOW. 5 months from now they add 20 more and the electrician looks at breaker size and ballast amps. He will never know about the cheap a-- that used #14 to save $1. He will more times than not even check amps now. I have many times added 1 or 2 more at 277 without asking or checking in factories because it would easily take an extra hour and 1 more man and shut down operations. I must rely on past electrician to not do something as stupid as under size a switch leg. that looks looks like a #12 circuit. I would checks amps at breaker and if close to 16 will walk away. Only hacks do garbage work like changing to #14. If your one of them please don't let me ever know. When we walk in on remodels we MUST assume what is there is correct and safe and only deal with what we add. If your one of them please then please find some job your qualified for , perhaps a garbage truck. Your messing with lves.

E'rrrr Jim, the #14 I was talking about was in reference to an AC unit, in post 113.

The allowance for fixture whips is only for one fixture per whip, but yes we see some who will Daisy chain many on one whip, this would not be allowed as would using a fixture whip as building wire in the case of the OP.

 

[Sierrasparky]

E'rrrr Jim, the #14 I was talking about was in reference to an AC unit, in post 113.

The allowance for fixture whips is only for one fixture per whip, but yes we see some who will Daisy chain many on one whip, this would not be allowed as would using a fixture whip as building wire in the case of the OP.

Boy the thread that will not die

 

[hurk27]

Boy the thread that will not die

Well just think of it as saving space, we have two topics in one thread