Generator Feed

[lowans]

Hi I am just wondering if anyone could shed some light for me as I am getting mixed opinions on this topic. We have a 400kva generator and a main distribution panel for the generator 20 feet away. The MDP is mlo fed straight from the generator with the breakers in the MDP covering 4 ATS's throughout the complex. Do we require to have a means of disconnection at the generator ?

 

[rlundsrud]

So there is no OCP for the wiring from the generator to the MLO? I would think you would need to have that protection in place as this wouldn't be covered by tap rule. That aside I would think you are ok as they 4 breakers do not exceed the 6 disconnect rule.

 

[augie47]

I find that a most interesting question.
Art 445.18 leads me to believe the generator would need to be equipped with a disconnecting means but does not mandate it have OCP, 240.21(G) assists in sizing but does not seem to dictate location.
I have no answer and look forward to others' comments.

 

[ron]

Does the generator have any inherent overcurrent protection?

For example,the Cummins control panel (PowerCommand Controls and AmpSentry) can provide the needed overcurrent protection for the generator output without a breaker.

 

[ron]

I find that a most interesting question.
Art 445.18 leads me to believe the generator would need to be equipped with a disconnecting means but does not mandate it have OCP, 240.21(G) assists in sizing but does not seem to dictate location.
I have no answer and look forward to others' comments.

I think 240.21(G) and 445.12 require overload protection, but not short circuit protection.