Interlock for 400amp service

[BDF]

I have a 400 amp service with 2 200 amp panels. I would like to install 2 separate interlocks (one on each panel) being fed by 2 separate portable generators. Is there any issue with these 2 panels both having a shared neutral back at the meter base? One electrician I spoke with thought there might be a phase issue and that there may need to be some sort of neutral disconnect installed on one of the panels. Another electrician I spoke with didn't think that was necessary and didn't see any problem with the plan for 2 generators supplying 2 panels with separate plug ins and separate interlocks for each panel.
I am planning to use 2 9500watt generators with 50 amp cb for each panel if there is way to do it.
Thoughts? Thanks!

 

[mike93lx]

Curious what you get for responses. I can't see why it would matter as this is not really any different than two neighbors both having generators.

 

[BDF]

That's exactly what the electrician that didn't see a problem said.
Also, just too add to the original post, the idea would be to have both generators running simultaneously, not one at a time.

 

[mike93lx]

Curious, what's the need to have it all backed up?

I have two 200's as well and moved a couple circuits around to allow just a single panel to be lit up in an outage. Just throwing it out there

 

[BDF]

Yes, I am considering that option as well. I have about 7 or 8 cb's in each panel that I want to back up so I don't think one generator would be enough and I would have the hassle of moving the circuits to the other panel.

 

[mike93lx]

Another option, you could feed the second panel from the first using an interlock in the second for the inbound power. Tying both together with appropriate disconnects.

 

[BDF]

Sounds like a good option. Would then only need just one larger generator

 

[Innovate1]

Curious, what's the need to have it all backed up?

I have two 200's as well and moved a couple circuits around to allow just a single panel to be lit up in an outage. Just throwing it out there

This is what I did. I have a small generator so only can run minimal things with the generator but at least I can switch which things are on at a given time (as long as they are on the interlocked panel).

 

[wyliesdiesels]

I have a 400 amp service with 2 200 amp panels. I would like to install 2 separate interlocks (one on each panel) being fed by 2 separate portable generators. Is there any issue with these 2 panels both having a shared neutral back at the meter base? One electrician I spoke with thought there might be a phase issue and that there may need to be some sort of neutral disconnect installed on one of the panels. Another electrician I spoke with didn't think that was necessary and didn't see any problem with the plan for 2 generators supplying 2 panels with separate plug ins and separate interlocks for each panel.
I am planning to use 2 9500watt generators with 50 amp cb for each panel if there is way to do it.
Thoughts? Thanks!

a phase issue with what? that makes no sense....

only thing you need to make sure of is that the neutral on the generators are not bonded....you only want a neutral bonded in one place and since youre not switching the neutral you need to make sure the generators have an isolated neutral.... portable generators typically have bonded neutrals.

 

[wyliesdiesels]

Another option, you could feed the second panel from the first using an interlock in the second for the inbound power. Tying both together with appropriate disconnects.

the problem with that is theyre both main service panels...

 

[mike93lx]

the problem with that is theyre both main service panels...

What's the issue?

 

[wyliesdiesels]

What's the issue?

if you feed one panel from the other the second becomes a subpanel

 

[mike93lx]

if you feed one panel from the other the second becomes a subpanel

Ah, interesting point.

Practically, would it likely matter in this application? I'm not advising to disregard code, just thinking out loud

 

[walta]

I think it would be a non-issue if the 2 generators are sync most inverter generators have an optional cable. Harbor Freight call it “PARALLEL READY DESIGN”. Other brands will have different names for similar function.

Walta

 

[mike93lx]

I think it would be a non-issue if the 2 generators are sync most inverter generators have an optional cable. Harbor Freight call it “PARALLEL READY DESIGN”. Other brands will have different names for similar function.

Walta

I don't see how that would be an issue. They won't be connected to each other

 

[BDF]

Thanks for all the replies! So it seems that there is no issue with my original plan of utilizing 2 generators feeding 2 separate power inlet boxes that supply 2 separate 200 amp panels configured with interlocks. Just need to make sure the neutral on the generators are not bonded.

 

[wyliesdiesels]

Thanks for all the replies! So it seems that there is no issue with my original plan of utilizing 2 generators feeding 2 separate power inlet boxes that supply 2 separate 200 amp panels configured with interlocks. Just need to make sure the neutral on the generators are not bonded.

you also need 4-wire cords between the generators and panels along with 4-wire inlets...

 

[dcg9381]

I have this setup.. Essentially. 320A service that splits into 2 x 200A panels.
200A panel A has an ATS and 20KW generator, feeds the house.
200A panel B feeds a shop sub panel. That panel has an interlock and a 50A generator inlet, covers the shop.

When my power fails, the house generator comes online by itself.

The shop provides power for our water supply (pump) - so if power stays down, I have to go down there are connect the generator if we want to use water.