3 Temporary generators one service

[Moosifer]

Customer has 3 non fused disconnects from a single utility feed. 200a, 200a, 100a. 240v single phase.
They want to be able to run 3 temporary generators.... one for each.
If I replace the disconnects with fused double throw switches (manual transfer switches) and give them what they need to power up with 3 different generators will they have an issue with the floating neutrals with 3 non-synchronized generators? Do they need to be separately derived systems with switched neutrals bonded in the generators and the generators grounded to earth? It seems like sharing the existing service neutral/ground will be an issue.

 

[Moosifer]

Nothing?

 

[kingpb]

Is this a separately derived system? Emergency, optional standby, or legally required standby systems may or may not be required to be grounded in accordance with the grounding rules for separately derived systems. If this is residential, then 250.30(A) for generator grounding applies.

 

[Moosifer]

Is this a separately derived system? Emergency, optional standby, or legally required standby systems may or may not be required to be grounded in accordance with the grounding rules for separately derived systems. If this is residential, then 250.30(A) for generator grounding applies.

Optional standby for commercial. It would be 3 standby portable generators with floating neutrals going to 3 fused manual transfer switches, each transfer switch fed directly from utility source (there are CT's for the meter) with bonded neutrals and no neutral switching in the transfer switches. Would that be safe & code compliant? I don't want it to pass inspection and not be safe.

 

[Hv&Lv]

I don’t know how the inspectors are in your area, but around here our inspectors are generally willing to offer an opinion or help.
For something like this I would call an inspector and see if he would meet me on site and discuss what you mentioned.
Then when your done and ready he is already familiar with what's going on.

 

[Little Bill]

I don’t know how the inspectors are in your area, but around here our inspectors are generally willing to offer an opinion or help.
For something like this I would call an inspector and see if he would meet me on site and discuss what you mentioned.
Then when your done and ready he is already familiar with what's going on.

We would have to buy a permit, called a "walk through" or "safety" inspection. Still might be worth it. Asking over the phone or text, no charge.

 

[shortcircuit2]

Customer has 3 non fused disconnects from a single utility feed. 200a, 200a, 100a. 240v single phase.
They want to be able to run 3 temporary generators.... one for each.
If I replace the disconnects with fused double throw switches (manual transfer switches) and give them what they need to power up with 3 different generators will they have an issue with the floating neutrals with 3 non-synchronized generators? Do they need to be separately derived systems with switched neutrals bonded in the generators and the generators grounded to earth? It seems like sharing the existing service neutral/ground will be an issue.

I don't understand the "non-fused" part of the existing service? Where is the overcurrent protection?

Other than that, multiple generators to feed one distribution system through separate transfer switches as "non-separately derived" will be Code compliant.

 

[Moosifer]

I don't understand the "non-fused" part of the existing service? Where is the overcurrent protection?

Other than that, multiple generators to feed one distribution system through separate transfer switches as "non-separately derived" will be Code compliant.

Cool, thank you. I believe the 3 panels they feed have main breakers but they are on the other side of the building. Unless they are fused and I didn't notice but they need to be switched to double throw anyway.