I will be working in a remote mountain location without available electricity. We explore for gold in case you are interested. We have an old mining shop available that has a 200 amp service (in good condition). We would like to power the shop with a 40 KW 240/120, 200 amp, single phase diesal generator (on wheels) that will be situated about 50 feet from the shop.

We plan to feed the shop in schedule 80 PVC underground from the generator:

1. There is currently no means of disconnecting the electric system between the generator and the building except by turning the motor of the generator off. Are we required to put a disconnect at the generator for overcurrent protection for the wire run underground from the generator to the building? The building panel has a main disconnect (set at 200 amps).

2. What are the grounding requirements at the generator? Are we required to ground the neutral at the generator? Currently, the shop panel is grounded using a single ground rod.

My answers follow your questions:

1. There is currently no means of disconnecting the electric system between the generator and the building except by turning the motor of the generator off. Are we required to put a disconnect at the generator for overcurrent protection for the wire run underground from the generator to the building? The building panel has a main disconnect (set at 200 amps).

Yes, something is needed to protect these feeders at the source.

2. What are the grounding requirements at the generator? Are we required to ground the neutral at the generator? Currently, the shop panel is grounded using a single ground rod.

Yes, ground the neutch at the genset, since this is a separately derived system.


The code can be reviewed online here:
NFPA 70: National Electrical Code®

The 2008 revision of the NEC code 445.18 states that generators need a disconnecting means that's lockable in the OPEN position except:

(1) The driving means can be readily shut off.

There is a cautionary statement as well: If a single generator is used to supply emergency power, as well as legally required or optional emergency power, there must be at least two transfer switches: One for emergency and one for standby.

Basically you have a transfer switch for emergency loads and one for other loads.

Kiss, the plan is to power a panelboard, not for emergency or standby power, no need for a transfer switch.

The feeders will need overcurrent and short circuit protection, not just disconnecting means.

Sure enough. Can't read.