cpickett
Senior Member
- Location
- Western Maryland
- Occupation
- Electrical Engineer
Have a customer that wants to add a manual transfer switch to allow for a portable generator connection for a remote plant (water treatment). See attached sketch. The service is 120/240, 1PH. On the pole with the meter is a 200A circuit breaker, with neutral-ground bond, and then SER is taken up the pole to a weatherhead and connected to triplex (2 insulated hots and an uninsulated neutral messenger), which goes across two poles, and then to a 200A load center on the side of the plant (it's skid mounted). There is also a triplex tapped off the second pole and taken to a small building that has another load center in it.
According to 240.21(B)(5) and 250.32(B)(1) Exception 1, I believe this install is to code (it was installed in the 70s). However, the customer wants to install a 200A manual transfer switch on the second pole (where the tap is), to allow for a portable generator hookup. If we modify this installation, do we have to bring 4 wires (2 hots, neutral and EGC) from the 200A breaker at the meter?
Also, do we need overcurrent protection at the generator inlet? The generator won't be permanently connected. The intent is that the customer can bring in a small generator (7kW) to just run the essentials, or he could rent a larger (48kW?) generator and power the whole plant.
According to 240.21(B)(5) and 250.32(B)(1) Exception 1, I believe this install is to code (it was installed in the 70s). However, the customer wants to install a 200A manual transfer switch on the second pole (where the tap is), to allow for a portable generator hookup. If we modify this installation, do we have to bring 4 wires (2 hots, neutral and EGC) from the 200A breaker at the meter?
Also, do we need overcurrent protection at the generator inlet? The generator won't be permanently connected. The intent is that the customer can bring in a small generator (7kW) to just run the essentials, or he could rent a larger (48kW?) generator and power the whole plant.