Taps for light and receptacle in a long bridge

[JohnPaul]

Hello everyone, I'm designing a circuit to power lights along the inside of a long bridge, 1000+'. I need a circuit run the length to provide power for a lights, receptacles, and bridge instrumentation at various intervals.

I propose using a 100A, 2P elec trip bkr that I can dial down to 30 or 40A. This would allow a #1 (needed for vdrop) to land on the load terminals as well as provide an adjustable OCPD. Field can alternate between the two hot legs to further distribute the load along the length of the circuit. At each load location I'll provide a splice box to tap and then provide a 15A fuse to protect the wiring to the light/recept.

1. Good idea or no? Any other ideas you've seen work?
2. Can I use a 100A Therm Mag vs the electronic trip with long time dial. That would be much less expensive and if fuses are at each load, would that be allowed per NEC?

 

[electrofelon]

Why not just provide a circuit breaker enclosure or small panelboard. Just run your conductors thru the enclosure and H tap onto them.

 

[JohnPaul]

I do plan to provide a panelboard. I think the best idea will be to install a large breaker where I can land a 2/0. I need the large wire because vdrop is an issue as the circuit is 1600' long. After more discussions, I am going to use a thermal mag breaker and install fuses at each tap.

 

[darekelec]

Reduce size of wire close to the breaker with Polaris taps. VD will not care about couple of feet of smaller wire.

 

[busman]

Also, you can get a Single Circuit Breaker enclosure for the larger frame circuit breakers with adjustable trip (see left side of photo below). Before you ask, I did not do this installation.

Mark

 

[hillbilly1]

Reduce size of wire close to the breaker with Polaris taps. VD will not care about couple of feet of smaller wire.

And the tap doesn’t even have to be in the panel. Use a large pull box close by where convenient.

 

[JohnPaul]

I should have noted that this is a 120/240V installation.

 

[tortuga]

I should have noted that this is a 120/240V installation.

You might consider omitting the neutral if the loads can be powered off 240V.
For sensors at a remote site I have used 240V -> 48 DC supplies etc.

 

[JohnPaul]

I need the neutral for receptacles so plan to alternate between the two 120V phases down the line.