Voltage Drop Calc

[joep]

I have an service application
275'
200 amps
240/120 Single phase

I do the math for feeders from the meter

2*275*21.4*200 / 7.2 volt (3% voltage drop on 240) = 326944

that said using table 8 c9 I need to use 350kcm al USD/USE

I was talking with the POCO and if we wanted the meter on the house it would still be a run of 275' but he would run 4/0 al

What did I miss????

 

[bphgravity]

There are a couple of considerations.

First, the voltage drop should be based on the calculated load not the service size. The demand on the service will likely never see 200A.

Second, the 21.4 K value for AL is a little conservative (high) and so is 3% on the feeders/service entrance.

Third, the POCO uses a different set of rules and requirements (NESC) when determining conductor sizes. They use different diversity/demand factors.