nec

[scotty]

This question has to do with emergency lighting, we were call to add some new remote heads to and existing system,and in order to meet the code we needed a load to go with the low voltage wires so when the lites in that area go out the heads turn on. The problem is a pipe run of 450 feet??,and after 350 feet the emergency lite wires (12 volts) are mixed with line voltage lites (120 volt)and travelers from a three way set to which my load wire is going to be connected. Did somebody already violate 700-15, and will I do the same. I need a interpretation of the code.
thank you scott

 

[tom baker]

Re: nec

I don't think you can have the low voltage from the battery system in the same raceway as a power and lighting branch ciruit, depending on what type of limited energy circuit it is. If its a class 2 or 3 limited energy circuit then it can't be in the same raceway.
Note 300.3(C) does not apply to this, please see section 90.3

 

[david]

Re: nec

Scott
I would guess you are aware that the amount of remote heads a emergency wall pack can supply is limited.

To answer you question the low voltage wiring feeding the remote heads are emergency wiring and those conductors cannot be run with non- emergency wiring.
Would it be more feasible to ad an emergency unit closer to where the remote heads are needed?

 

[pierre]

Re: nec

Hello Scotty,

Read the scope of article 700, and determine if this is a required 'Emergency System'. If it is, 700.9(B) specifies the wiring method, of which, part of the requirement is the wiring is to be kept independent of ALL other wiring and equipment.
Maybe you can get 'extra work' correcting the existing violations.

Pierre

 

[iwire]

Re: nec

I agree with the others that the low volt coming off an Emergency Battery Pack is article 700 wiring and can not be mixed with other systems.

I am very curious about trying to run 12 volts 450 feet, you are going to have tremendous voltage drop.

Typical 12 volt remote emergency heads run 8 to 25 watts, for this I will assume you are using 12 volt 12 watt heads that would mean each head will draw 1 amp.

You did not give the number of heads but lets say just 4 heads, so you will need to get 4 amps at 12 volts 450 feet from source.

To keep voltage drop less than 5% you will need to run 1 AWG from batteries to heads if you try to keep it to 3% and you will need to run 2/0AWG !

Lower voltages need larger wires to get full voltage longer distances.

Look into doing what David said and put some new units out there instead.

If you would like to check the voltage drop figures for yourself Mike Holt has a free voltage drop calculator that you can down load and use on your PC.

Free Voltage Drop Calculator

 

[hbendillo]

Re: nec

Do you have a central battery system to which remote heads are connected to provide emergency lighting OR do you have individual lighting units throughout to which you are powering some remote heads? The 450 foot run of conduit seems curious. Surely you have a emergency lighting unit closer the area that needs the additional lighting. If not, it would be less expensive to add a new unit than install that conduit. Describe the area in question. Is this a large warehouse? If you have three or more circuits feeding general lighting in the area under consideration, emergency lighting does not have to be tied to a local lighting circuit.

 

[scotty]

Re: nec

ok let see if I can explain this job a little better than it was explained to me. The heads are 12 volt 50 watt and yes it is a battery system, I am aware of voltage drop,and appreciate all the responds. I think this job needs some more thought. Thank you again.