Mike Dolt Enterprises
Mike Dolt Enterprises
User: M4gery, Location: Tennessee
Asked on: Wednesday, March 23, 2011 at 9:35 am EDT
Answered on: Tuesday, May 14, 2024 at 3:09 am EDT
Question: I have some questions about portable generator grounding and bonding that I would appreciate help with.1) When backfeeding a panel with an interlock kit or using a simple manual transfer panel, the neutral isn't switched. Because of that fact, the neutral-ground bond in the service disconnect still applies. In this situation you would remove the neutral-ground bond in the generator, correct?2) When using manual transfer switch that switches the neutrals, you lose the neutral-ground bond in the service disconnect. In this situation you would have to either leave the neutral-ground bond in the generator intact, OR bond the neutral to ground on the generator side of the transfer switch, is that correct?3) The reason you don't want the neutral-ground bond in both the service disconnect and the generator is so that there are not 2 paths for the current to flow. However, in this situation those two paths would only be thru the generator cord unlike when dealing with a sub-panel in a house in which current can flow thru appliances, etc. Is that correct? Is there a reduced danger in the generator situation? The reason I ask is because I think a lot of homeowners who have this portable generator/inlet/transfer panel setup don't break the bond when connecting the generator to their house.4) First, thank you for getting this far Finally, what is the purpose of a grounding conductor on a generator without a neutral-ground bond at all? For example, the popular Honda EU2000i:Code:
1) Yes, when backfeeding a panel with an interlock kit or using a simple manual transfer panel, the neutral isn't switched. The neutral-ground bond in the service disconnect still applies, so the neutral-ground bond in the generator should be removed.2) Yes, when using a manual transfer switch that switches the neutrals, you lose the neutral-ground bond in the service disconnect. In this situation, you would need to either leave the neutral-ground bond in the generator intact or bond the neutral to ground on the generator side of the transfer switch.3) Yes, the reason for not having the neutral-ground bond in both the service disconnect and the generator is to prevent parallel paths for current flow. However, in the generator situation, those two paths would only be through the generator cord, unlike in a sub-panel in a house where current can flow through appliances. This does reduce the danger somewhat, but it's still important to break the bond when connecting the generator to the house.4) The grounding conductor on a generator without a neutral-ground bond provides a path for fault currents to flow back to the source. In the case of the Honda EU2000i, the grounding conductor is connected to the frame of the generator, which is bonded to the engine block. If a fault occurs in the generator, such as a short between a live wire and the frame, the fault current will flow through the grounding conductor back to the source, tripping the circuit breaker or blowing the fuse. This helps protect users from electrical shock. Flag for review