15 amp outlet circuits in commercial bldg

[richwaskowitz]

What rule could in inspector site that would prohibit running #14 for convenience receptacle branch circuits protected by 15 amp breakers (I know. I should ask him, and I will later)? I would not do this myself (run #14), but some folks I know did this in their tanning salon and the inspector has them replacing it all with #12 (about 1000 feet of it). The 180 VA rule was not exceeded. If this is his (local rule)call, that is OK and they should comply, but is it prohibited by the NEC?

 

[ryan_618]

Re: 15 amp outlet circuits in commercial bldg

Could there be a derating issue? I did an inspection yesterday where the feeder circuits for a multi family went from 100amp conductos to 50 amp conductors because of current carying conductors in a raceway.

 

[richwaskowitz]

Re: 15 amp outlet circuits in commercial bldg

No, I don't think so. There was no bundling of cables. There were only 5 or 6 outlets on each circuit. I don't know why the guys used 14 but they did. I am not going to argue with the inspector if it is his call. I just want to know if this is a code violation or just their local rule.

 

[charlie b]

Re: 15 amp outlet circuits in commercial bldg

It's not a violation of the NEC. I can't speak for local codes or building codes.

 

[ronson]

Re: 15 amp outlet circuits in commercial bldg

if all the receptacles were on the same 1000 feet of #14, i might see where inspector would want #12 used for voltage drop. what kind of equipment was plugged into receptacles? maybe inspector felt salon was in danger of overloading ckt. call that inspector & ask him. let us know what you find out.

 

[ryan_618]

Re: 15 amp outlet circuits in commercial bldg

Originally posted by ronson:
if all the receptacles were on the same 1000 feet of #14, i might see where inspector would want #12 used for voltage drop.

Voltage drop is beyond the scope of the code. It is a design issue.

 

[richwaskowitz]

Re: 15 amp outlet circuits in commercial bldg

No, no, no. Let me clarify. There were several circuits totalling the 1000 feet. No one circuit had more than 5 or 6 outlets. They are intended for radios and portable fans in the tanning rooms as well as general purpose use such as table lamps and vacuuming the floor.

 

[pierre]

Re: 15 amp outlet circuits in commercial bldg

If not a local code, I say the contractor got burned

Pierre

 

[iwire]

Re: 15 amp outlet circuits in commercial bldg

Originally posted by richwaskowitz:
There were several circuits totalling the 1000 feet.

If these several circuits are all in the same raceway the problem could very well be what Ryan has suggested.

Could there be a derating issue?

5 two wire circuits in one raceway would be subject to derating problems.

14 AWG = 25 amps 310.16

5 two wire circuits = 10 current carrying conductors

10 conductors gets a 50% downward adjustment Table 310.15(B)(2)(a)

25 x .5 = 12.5 amps

You should not feed 15 or 20 amp duplex outlets with a 10 amp breaker.

You can not move up to the next breaker size. 240.4(B)

This would mean you would have to use 12 AWG on the 15 amp breaker.

[ March 06, 2004, 01:02 PM: Message edited by: iwire ]

 

[tshea]

Re: 15 amp outlet circuits in commercial bldg

I most certainly would ask the inspector what the violation is, and have him cite the code article.
Our inspectors are that way...they tell us 310.16 or whatever, unless it's a dumb mistake...missed a ko closure.
I definately would ask the inspector! Don't try to second guess. :roll:

 

[ronson]

Re: 15 amp outlet circuits in commercial bldg

ryan, even if voltage drop is a design problem, wouldn't an inspector refuse a 1000' run of #14 that had a serious voltage drop? i know a couple that i am pretty sure would. can voltage drop not cause equipment to burn up & pose a fire hazard?

[ March 07, 2004, 01:03 AM: Message edited by: ronson ]

 

[iwire]

Re: 15 amp outlet circuits in commercial bldg

Originally posted by ronson:
even if voltage drop is a design problem, wouldn't an inspector refuse a 1000' run of #14 that had a serious voltage drop?

Unless there is a local written code covering voltage drop an inspector can not fail an installation for voltage drop.

Inspectors are only supposed to be enforcing the written rules, not making ones up as they see fit.

 

[charlie]

Re: 15 amp outlet circuits in commercial bldg

Since this is a commercial installation, the available fault current may be too high for #14 wire to be used without exceeding their withstand rating. There are a very few jurisdictions around here that enforce that for commercial and industrial installations.

 

[iwire]

Re: 15 amp outlet circuits in commercial bldg

Charlie while that makes perfect sense, what code article could be used to enforce that?

110.9 is the only one I can think of but I would not think a conductor is "Equipment intended to interrupt current at fault levels"

Bob

 

[ryan_618]

Re: 15 amp outlet circuits in commercial bldg

Originally posted by ronson:
ryan, even if voltage drop is a design problem, wouldn't an inspector refuse a 1000' run of #14 that had a serious voltage drop? i know a couple that i am pretty sure would. can voltage drop not cause equipment to burn up & pose a fire hazard?

I would bring it up on my inspection as an item that the installer should be aware of, be if the installer didn't want to fix it, I couldn't make him.

 

[ronson]

Re: 15 amp outlet circuits in commercial bldg

ryan, that's good to know. the next time an inspector gets horsey with me regarding my installation methods i'll tell him to get lost.

 

[ryan_618]

Re: 15 amp outlet circuits in commercial bldg

Originally posted by ronson:
ryan, that's good to know. the next time an inspector gets horsey with me regarding my installation methods i'll tell him to get lost.

 

[charlie]

Re: 15 amp outlet circuits in commercial bldg

Bob, take a look at 110-10 "The overcurrent protective devices, the total impedance, the component short-circuit current ratings, and other characteristics of the circuit to be protected shall be selected and coordinated to permit the circuit-protective devices used to clear a fault to do so without extensive damage to the electrical components of the circuit."

IMO, wire is a component of a circuit and must be protected. If it is protected with current limiting devices, I see no problem with using #14.

 

[iwire]

Re: 15 amp outlet circuits in commercial bldg

That sounds good Charlie.

The jobs I work are all engineered with specs and I can not think of one that the specs did not require 12 AWG min. for line volt circuits.

Bob