Voltage Drop?

[tyha]

We have some Cellular equipment on the roof of an existing building. The euipment itself doesn't pull but about 20amps, but they set a 200amp panel and we feed it with 3/0 200amp service. the run is about 120' long and they are saying they are only getting 100 volts per leg with 185 in between. is this voltage drop. its only 120' long and its already in 3/0. The pull from what I understand was a pain in the but, so pulling the cable out is not an option. However, about 25' from the switchboard downstairs, where we started our feed from, there is a junction box where we spliced and installed ct's. What other things should I have checked out?

 

[iwire]

I would check the voltage at the source and compare it to what you have at the roof.

I would also ask to see the meter they used to check the voltage.

Ideally you will use a true RMS meter.

If the load is as small as you suggest there is no way you should have that much VD for 120' of 3/0.

 

[tyha]

I think they are checking it with no load at all. Would that make a difference. There wouldn't be any resistance.

 

[JohnJ0906]

I think you need to check it yourself. This doesn't sound right. 20 amps on 3/0 shouldn't have any appreciable voltage drop at all.