Generators

[hurk27]

I agree with that.




If you were to apply that though then each of the two gen sets would be none seperately derived systems because they are each tied to another system.
The definition of SDS does not change the wording in 250.20(D). If the wording had said "or to another alternate source", then things would be a little clearer.

Rick

So either the definition in artical 100 is flawed, or the FPN in 250.20(D) is?
because if the generators are not a SDS as defined in artical 100, 250.20(D) would not apply?

 

[RUWired]

So either the definition in artical 100 is flawed, or the FPN in 250.20(D) is?
because if the generators are not a SDS as defined in artical 100, 250.20(D) would not apply?

If both gen sets are solidly connected, neither of the two are SDS's and neither would require the system bonding jumper which would be a violation of 250.20(B). So the only way to make it compliant is to have a switched neutral transfer switch inplace. This would make the definition correct and allow 250.20(D) to come into play.

Rick

 

[Cold Fusion]

If both gen sets are solidly connected, neither of the two are SDS's and neither would require the system bonding jumper which would be a violation of 250.20(B). So the only way to make it compliant is to have a switched neutral transfer switch inplace. This would make the definition correct and allow 250.20(D) to come into play.

Rick

Maybe not. Here is the normal method I've seen on most multiple gen systems (with no utility) I've seen.

Each gen is 5wire to the main switchboard. All of the neutrals land on the neutral bus. All of the Equipment Grounding Conductors land on the Ground bus. Each gen has it's own 3pole cb at the main switchboard. The NG bond is at the main switchboard.

For maintenance, each gen has a 1pole neutral disconnect switch that can be locked open when the gen is being serviced. This is not required by code, but it sure helps the maintenance crew.

Now why would this not be code compliant?

cf

 

[RUWired]

Now why would this not be code compliant?

cf

CF your installation sounds code compliant because you are providing an OCPD in the switch board. In post 16 i had said if the transfer switch did not have OCP then it would be a violation of 250.30(A)1. Maybe "the only way" was too general. There are other ways to make it code compliant besides your method, but i was keeping with the OP's original thought of installing a 4-pole switch.

Rick

 

[Robert Hutcherson]

I agree 100% with the installation that "SLECT" described.