Genterator grounding

[dwellselectric]

Okay we have a 12kw genterator and the service does not have any ground rods it is only grounded by the cold water pipe. My boss asked me a question today and I dont know if I am right. He asked me where the best place to ground the system at was (install the ground rods). I said ground it at the meter. My question is, is there a better place to put the ground rods or does it not matter? And do we have to drop a ground rod at the genterator? its about five feet from the house

 

[bphgravity]

A service is to be grounded at any location specified in 250.24(A)(1). The meter socket enclosure is one option if permitted by the local power company.

A grounding electrode system is only required at the generator if it serves as a separately derived system under the requirements of 250.30 of the NEC or if required by the manufacturer's instructions per 110.3(B) of the NEC.

 

[tryinghard]

You have a couple of issues here: 1) the water sounds like the electrode in this application and 250-53(D)(2) requires you to use additional electrodes as listed in 250-52(A)(2) through (A)(7), in other words the water pipe cannot be used as an electrode by itself. I recommend looking around you may find it is supplemented with a ufer 250-52(A)(3) but you must install a supplemental for the main service electrode system.

2) Your generator feeder will have to be a 4W if the transfer switch does not break the neutral (most common), feeder needed: A, B, N, & GR sized as per table 250-122. If the neutral is switched (uncommon) then it is a separately derived system and you will have to re-establish the ground just like a service disconnect by making common the neutral with electrode and case, and in this example the feeder needed would be: A, B, & N sized as per table 250-66.

 

[dereckbc]

Is the generator SDS or not?