goldstar said:
However, the more posts I read here makes me think that I did something completely wrong. I think the basic problem is determining whether the portable generator is considered a SDS or not. I don't want to shift attention away from the original question but if anyone can point me in the right direction here it would be greatly appreciated. Thanks.
The basic problem can be answered by a very basic answer.
The transfer switch and the generator need to have matching setups.
If the transfer switch transfers the neutral, the generator must have a main bond between the neutral and equip ground. . This is the SDS, separately derived system setup.
If the transfer switch
doesn't transfer the neutral, the generator must
not have a main bond. . This setup is commonly referred to as "subpanel" wired or "floating" neutral generator.
It's really as simple as that.
If the transfer switch transfers the neutral, you get
cut off from your neutral connection to the main bonding point so therefore must establish a
new main bonding point for generator power. . The position of the transfer switch determines which power supply is used and
also which bonding point is being used.
If the transfer switch
doesn't transfer the neutral, the main bond at the utility service disconnect
continues to function as the single bonding point
regardless of the transfer switch position. . It's the single bonding point while utility power is supplying
or while the generator is supplying.
goldstar said:
All the circuits in the sub-panel were emergency circuits (gas pumps, lights, air compressor and a few receptacle circuits). The 40 circuit, 200 amp CH panel was packed with wires and making additional splices in it would have made the situation worse, so I installed the sub-panel. As I mentioned, with the transfer switch in the POCO position all neutrals were bonded to the EGC via the main breaker panel.
The addition of subpanels doesn't change anything either way. . If its a SDS setup or not, subpanels continue to be subpanels, it's only the generator connections that vary according to the transfer switch setup.
If your situation makes the use of an additional subpanel or two desirable, go right ahead and add them. . It doesn't affect the bonding question.
goldstar said:
The neutral at the 30 amp twist lock receptacle of the generator was a floating neutral (according to the manufacturer's rep).
..... As I mentioned, with the transfer switch in the POCO position all neutrals were bonded to the EGC via the main breaker panel. When transferred to generator the neutrals floated. This is the way it was installed based on the engineer's recommendation.
If the engineer or manufacturer is requiring or recommending generator bonding either one way or the other, then that shouldn't be a problem to comply with their desire. . You just have to match up the right
transfer switch according to how they want the generator bonded.
David