Tap conductors outdoor lighting

[jjbeluga]

I have a 1000 ft perimeter outdoor lighting run. Voltage drop and temperature derating has the homerun at #6 awg. Can I tap off the main run with smaller wire to connect to the individual fixtures. I see in Article 410-67(C) where you can have tap conductors no greater than 6 feet in length. In Article 210-19(4) exception 1 which tells me the minimum wire size on a 40 amp or larger circuit must be 20 amp.

So if my home run is #6, The breaker for this circuit is 40 amps, then I could tap off the homerun with #12 wire to feed each fixture as long as it is not over 6 feet in length?

Thanks for the quick replies. This 1000 ft run is to the further most lights. I will have 10 175 watt 380 volt Metal Halide wall packs on the run. Site voltage is 220/380 volt 50 hz and the breaker will be a 2 pole 40. Don't really need this large a breaker but the shorter runs have more lights on the circuit so I was just keeping the breaker size the same as the wire is large enough. I figure each light will draw about 2.17 amps. Ambient temperature derate is .82 and I calculated the voltage drop at a little over 5%. I was going to run a #10 awg ground with this. The distance between lights is 30 feet with the 1000 foot mark being the last light. I am running two separate two wire 380 volt circuits and hitting every other light.

So at each of the Tees on the main run I was wanting to splice #12s to go from the main run to the fixture.

 

[iwire]

I have a 1000 ft perimeter outdoor lighting run. Voltage drop and temperature derating has the homerun at #6 awg.

6 AWG sounds small to me for a 1000' run.

Can I tap off the main run with smaller wire to connect to the individual fixtures.

Yes, but they do not necessarily have to be 'taps'.

So if my home run is #6, The breaker for this circuit is 40 amps,

Is there any reason you need to use a 40 amp breaker?

If you do don't forget about 210.23(C) (Requires the fixtures to have 'heavy duty' lamp holders.

What size grounding conductor did you run?

250.122(B) requires the EGC to be increased when you increase the circuit conductors.

If you give more info like the number of fixtures, the wattage and the voltage the members here can give you some more help.

If you need a 40 amp breaker due to the amount of load you will have some serious voltage drop on 6 AWG 1000' long.

 

[George Stolz]

JJBeluga, welcome to the forum. It is less confusing if you simply hit the "Post Reply" button and respond to the replies you receive, if more information is to be added for clarification.

Site voltage is 220/380 volt 50 hz and the breaker will be a 2 pole 40.

I notice this is not a North American voltage. Are you sure the NEC applies to your installation?

I see in Article 410-67(C) where you can have tap conductors no greater than 6 feet in length.

What you might not have noticed is the heading of the Part that section resides in: Part XI. Special Provisions for Flush and Recessed Luminaires (Fixtures). You are not installing recessed cans out there, this Part does not apply to your installation.

One item I'm not clear on: are there 10 lights total, spread out over two 380V circuits? Or are there 20 lights on the two 380V circuits?

If there are 10 lights, at 2.1A apiece, that's 21A. Split over two circuits, is 10.5A apiece. There would be no reason not to use two two-pole 20A breakers to supply the two circuits.

In the scenario you described, without knowing the conductor types in question I would say you have a 250.122(B) violation until you increased the wire size to #8 on your equipment grounding conductor (EGC).

 

[jjbeluga]

Hi George,

Thanks for the tip on using the forum better. It is a foreign location. But we are contractually bound to follow the NEC.

Out here I have only me, myself and I to answer questions. I am fairly certain it is a good installation the way I described it to you all. I just wanted to be sure. I never expected to be tossed into having to do all the job planning.

Thanks

 

[George Stolz]

As it stands, I don't believe the installation described is compliant.

Could you answer the last question:

One item I'm not clear on: are there 10 lights total, spread out over two 380V circuits? Or are there 20 lights on the two 380V circuits?