I have a customer with a machine shop. He has all sorts of milling, CNC, grinding, welding, equipment, etc.
He keeps adding, and adding more machines, and equipment. He has an 800 amp 480 service, that drills down to several different size and type of systems, single phase, three phase, 480, 120, etc.
His shop was originally set up for what he had then with not much room for more load.
I've added more equipment to various systems, each time telling him that he can not use the machines on that feeder at the same time because he'll trip out the breaker.
He always tells me that it's no problem because what machine gets run depends on the job being done, and there is little chance of running too much at the same time.
I get permits, and inspections. Conductors and disconnects are installed as required. Therefore it's always passed inspection. But it's such a complex layout that an inspector has never really looked at whats there. There has never been a breaker trip yet.
An example, there may be two or three 60a milling machines connected to one 60 amp circuit. Only one gets used at a time.
Once again he's called me up and indicated that he's adding more equipment. He wants me to set up more on "shared branch circuits".
Is this approach really code compliant? I can't find a code reference that would forbid this. This is an industrial environment, and he has a shop supervisor on the floor at all times. The supervisor is a machinist though, and not a certified electrician.
Rick
He keeps adding, and adding more machines, and equipment. He has an 800 amp 480 service, that drills down to several different size and type of systems, single phase, three phase, 480, 120, etc.
His shop was originally set up for what he had then with not much room for more load.
I've added more equipment to various systems, each time telling him that he can not use the machines on that feeder at the same time because he'll trip out the breaker.
He always tells me that it's no problem because what machine gets run depends on the job being done, and there is little chance of running too much at the same time.
I get permits, and inspections. Conductors and disconnects are installed as required. Therefore it's always passed inspection. But it's such a complex layout that an inspector has never really looked at whats there. There has never been a breaker trip yet.
An example, there may be two or three 60a milling machines connected to one 60 amp circuit. Only one gets used at a time.
Once again he's called me up and indicated that he's adding more equipment. He wants me to set up more on "shared branch circuits".
Is this approach really code compliant? I can't find a code reference that would forbid this. This is an industrial environment, and he has a shop supervisor on the floor at all times. The supervisor is a machinist though, and not a certified electrician.
Rick