Grounding and proper installation of residential generator

[mshields]

A friend of mine just bought a 20kW generator which he plans to set up with permanent connections. His plan is to reroute the service to a new MTS. Second input to the MTS obviously will be the generator and the output will be the existing service panel.

Doesn't he need to have a new service disconnect ahead of the ATS?

Also, He's got SER cable feeding into his panel now, 2 phase and a grounded service conductor. If he adds a new service disconnecting means as I'm suggesting above, doesn't he need to run from there his 2 phase, 1 neutral and a ground. Only the service can be the 3 wire stuff correct?

On the generator side, again, he plans on using 3 conductor SER cable, I would think he'd need the separate neutral and ground.

Lastly, since the MTS is 23 pole only, I believe there should be no neutral to ground bond at the generator. Do you agree?

Very much appreciate your input.

Thanks,

Mike

 

[texie]

A friend of mine just bought a 20kW generator which he plans to set up with permanent connections. His plan is to reroute the service to a new MTS. Second input to the MTS obviously will be the generator and the output will be the existing service panel.

Doesn't he need to have a new service disconnect ahead of the ATS?

Also, He's got SER cable feeding into his panel now, 2 phase and a grounded service conductor. If he adds a new service disconnecting means as I'm suggesting above, doesn't he need to run from there his 2 phase, 1 neutral and a ground. Only the service can be the 3 wire stuff correct?

On the generator side, again, he plans on using 3 conductor SER cable, I would think he'd need the separate neutral and ground.

Lastly, since the MTS is 23 pole only, I believe there should be no neutral to ground bond at the generator. Do you agree?

Very much appreciate your input.

Thanks,

Mike

I would agree.

 

[suemarkp]

Is the MTS Service rated?

I'm assuming you mean he has SE cable (3 conductors), not SER (which has 4)?

MTS is 23 pole?? Do you mean 2 pole, so that the neutral is not switched?

 

[mshields]

response to Mark

response to Mark

Yes Mark, 3 cable, SE cable.

I'm going to assume the MTS is 2 pole. I believe the only impact, correct me if I'm wrong is that if it's solid, you don't bond at the generator, if it's switched, it becomes a separately derived service and you do bond. Do you agreed?

As for the MTS, are they available as service rated. I don't know why they would be since they are not a disconnecting means?

 

[jxofaltrds]

Mike start here. Now this is not the only way.

You should note that odds are the generator will come bonded.

Use this to understand and not to design!

 

[qcroanoke]

Mike start here. Now this is not the only way.

You should note that odds are the generator will come bonded.

Use this to understand and not to design!

View attachment 9585

You should also note you can take that loose.

 

[suemarkp]

Yes Mark, 3 cable, SE cable.

I'm going to assume the MTS is 2 pole. I believe the only impact, correct me if I'm wrong is that if it's solid, you don't bond at the generator, if it's switched, it becomes a separately derived service and you do bond. Do you agreed?

As for the MTS, are they available as service rated. I don't know why they would be since they are not a disconnecting means?

You can get Service rated ATS's and MTS's (MTS may be listed as a Safety Switch not necessarily a Transfer Switch, but it should have a center off position). A service rated MTS I had did not have overcurrent protection, so it would have to be immediately adjacent to a panel with a breaker or fuse. The original main panel could be that breaker. The transfer switch will have to be Service Rated if it is where the Service Conductors land and it becomes the main disconnect.
You need 4 conductors from the transfer switch, since the transfer switch will be the disconnect, and will need to split out the neutrals and grounds in the old main panel. So need SER cable, not SE.
You need 4 conductors from the generator to the transfer switch since it is a solid neutral switch. Again, SER cable needed, not 3 conductor SE.

 

[qcroanoke]

You can get Service rated ATS's and MTS's (MTS may be listed as a Safety Switch not necessarily a Transfer Switch, but it should have a center off position). A service rated MTS I had did not have overcurrent protection, so it would have to be immediately adjacent to a panel with a breaker or fuse. The original main panel could be that breaker. The transfer switch will have to be Service Rated if it is where the Service Conductors land and it becomes the main disconnect.
You need 4 conductors from the transfer switch, since the transfer switch will be the disconnect, and will need to split out the neutrals and grounds in the old main panel. So need SER cable, not SE.
You need 4 conductors from the generator to the transfer switch since it is a solid neutral switch. Again, SER cable needed, not 3 conductor SE.

Bingo! could not have said it better!