400A service, long feeders

Status
Not open for further replies.
B

Bbaum950

Member
Location
Ohio
Occupation
Journeyman inside wireman
All,

I’ve been asked to clean up after a contractor who wired a very large home, but did not do anything from the utility to the home (not sure why). It’s a bit of a unique situation as far as my experience with anything like it, but here’s what’s up:

Homeowner lives on a territory line with two POCOs and basically is on legal hold with one of them as there is a lot of bad blood and they will not release him so the other POCO can bring the service the entire way to the home (crossing the territory line) so the homeowner is stuck with option #2 which is have the POCO he is on better terms with bringing the primary to the territory line and having me set a meter there and run the secondary to the house. The issue is that the meter and xfmr from the power company will be at best 500’ away from the home.

The home has two 200A main breaker panels with two separate feeders stubbed out of the top waiting to be connected to the utility, so it’s a 400A service at this point (homeowner had no idea what he even had in the basement of his new home). Voltage drop calculations have me pulling parallel sets of 750s to prevent voltage drop at full amperage at a distance of 500’ but there’s potential it could be further.

I’m struggling with what to do here to fight the distance variable but there’s not much I can do to get the primary closer to the home, so I was thinking of asking the POCO to step the voltage down to single phase 480 and run it to a 100kva 480 to 240 single phase xfmr at the house so I can have 200A from the meter to a disconnect (primary side of my xfmr)p, hit the xfmr and get my 240 @ 400A for the service and feed both panels.

Am I overthinking this one? What would you all do? I’m licensed but do mostly industrial controls so I don’t have a ton of experience with sizing services other than what it took to pass my test and this one is a little odd to me to begin with.
 
500’ is not really a super long distance, I’ve done what you are talking about doing for a much longer distance (1500’ +). (Except I stepped up with my own transformer to 240/480, then back down to 120/240 at the end.)You need to do the voltage drop calculation for the actual calculated load instead of the full 400 amps, that would probably reduce your wire size substantially.
 
hillbilly1 said:
500’ is not really a super long distance, I’ve done what you are talking about doing for a much longer distance (1500’ +). You need to do the voltage drop calculation for the actual calculated load instead of the full 400 amps, that would probably reduce your wire size substantially.
Click to expand...
Thanks for the reply. I think you’re right on that, I feel like it’s a bit excessive and I don’t think there’s as much load as they sized the service for. Every appliance that can be gas will be, so the only load is the air conditioner and lighting.
 
tom baker said:
With major loads being gas your connected load will be much less than 200A
Click to expand...
I’m not sure why the contractor installed two 200A panels in the first place. They’re side by side and neither is full, could’ve gotten away with a 42 circuit panel but they did it this way with two separate feeders and the homeowner was not really aware of what was going on so it wasn’t by request. Oh well.
 
Status
Not open for further replies.
Top