greg, I'm only trying to calculate according to what he already has. I will be adding a 277/480 volt service on the other end of the building to take care of other motors. I just want to make sure that my calculations are right. If this was a new installation, I would definitly put in at least a 400 amp. 120/240 service. That is my point in asking, whether to tell the owner that he will have to change the existing service or not. That will bring up questions also, because he is under the assumption that the service is capable of handling the machines, because someone from the inspection office, ( he assumes ), says that the service is alright. I have my doubts about that though, since I don't think he gave them all the necessary information.
According to what I have come up with on my calculations, I take 125% of the largest motor, and add the total amps of the other motors for the feeder for the sub panel, then for the service size, I take the lighting loads and recept.loads per tables 220-3(a) and table 220-11 and other loads, then divide by 360?? Does this sound right. He has other motors he wanted to put on this service, but the way I see it they will have to be changed to 460 volts and taken out of the other service panel that I am to add, if
he can get by with the minimal machines on the exisiting 120/208 service. Since there are no prints for this job, and there is quiet a bit of confusion between the owner and inspection office, and ME, I'm trying to go the simpliest way and the safest way possible under the circumstances. Like I said, if this was a new installation, I would do it quiet different, but we're trying to make what is available work in as much as possible. As last resort, I may have to tell him that the existing service will have to be changed, but I want to make sure I am telling him right. This is a big expense other than the expense he is already taking.Thanks.. Steve ... Also the 460 volt service was already there on the other end of the building, only the previous owner took the panels with him, and only left the parralled service conductors in a 2 X 2 juncion box. As a matter of note here, he must have disconnected them "hot", seeing that there was still power on the wires. Thankfully he did leave them taped up.... I had to get the local power company to kill the power on them [Linked Image] Like I said, I'm preparing for what to tell him ...

[This message has been edited by sparkync (edited 03-17-2005).]

[This message has been edited by sparkync (edited 03-17-2005).]