Portable Generator Neutral

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nuckythompson

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Location
Nova Scotia
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Electrical
Hi there, I have seen installations where the generator is connected directly to the main house panel through a breaker. When the power goes out they shut the main breaker and close the generator breaker to power the panel. No transfer switch.

My question is, what happens with the neutral? If the generator was connected to the main panel neutral, wouldn't you have current flowing out to the grid on that neutral?

If a transfer switch is installed, how does this separate the neutral?

Thanks :)
 
nuckythompson said:
My question is, what happens with the neutral? If the generator was connected to the main panel neutral, wouldn't you have current flowing out to the grid on that neutral?
Click to expand...
No. The panel is disconnected from the grid and the neutral current returns to the source which is the generator. You can use a transfer switch that also switches the neutral but then the generator become a SDS which means among other things that it has to be connected to a GES. The typical residential system employs a generator inlet, a back-fed breaker and a breaker interlock. The neutral in the generator is not bonded to the generator frame. The MBJ in the service disconnect still acts as the point where the neutral is bonded.
 
nuckythompson said:
My question is, what happens with the neutral? If the generator was connected to the main panel neutral, wouldn't you have current flowing out to the grid on that neutral?
Click to expand...
To provide a more basic answer, in order for current to flow, you need a complete circuit, a loop. So with only one wire connected between the grid and the generator, the neutral conductor, there's no circuit and no current flow.

Cheers, Wayne
 
Many of the larger size portable generators (ie 30A 240V and up) have instructions on how to un-bond the neutral and ground in the generator.
 
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