I have not thoroughly looked at this job, I'm going by what the maintains man has told me, I plan on looking at it
tomorrow. 1600 Amp service, four runs of 750? Aluminum, over the 30 years one run has lost a conductor ( shorted out against the
metal conduit). This is a 200'+ run. They are going to increase a 200 HP motor to a 300 HP so they want the service conductors fixed.
So it looked like a matter of trying to pull out the old conductors and replacing with new 750 AL.
My question is the concern if this is a service or a sub feed to the 1600 AMP MDP. A few years back they put in a generator that would
supply the entire location, a feed mill, a elevator and fertilizer building. So are these sub feeds going out from the transfer switch or are they still each independent services?? 750 MCM AL = 385 * 4 = 1540 or 900 MCM AL = 425 * 4 = 1700 Amps
Can four copper conductors be used in one run and keep the existing runs of Aluminum?
If it's possible it probable wouldn't happen anyways, copper costing 2 3/4 times more than Aluminum.