unfamiliar generator transfer switch

[Greg1707]

This photo was taken at an all electric house with a 200 amp main service panel in the basement. The main panel has a main bonding jumper and GEC system.

Outside there is a propane powered generator. This is a photo of the meter and equipment for generator. The box on the right of the meter has a 100 amp breaker.
I don't understand this setup. There are no modifications to the main panel. If this is a transfer switch, how does it accommodate the "whole house?"

 

[kwired]

Knowing what else is behind the cover would be a big help at an attempt to answer the question.

Kind of looks like we may potentially have two service disconnecting means for a single structure that are not grouped together.

 

[GoldDigger]

Knowing what else is behind the cover would be a big help at an attempt to answer the question.

Kind of looks like we may potentially have two service disconnecting means for a single structure that are not grouped together.

Blowing up the image to max, it looks like either a manual transfer switch or a breaker inside the box, behind clear plastic cover.

The service seems to be coming up to the meter and down the conduit towards the panel in the basement, with no disconnect at the meter.

There is a similar conduit going down toward the basement and a smaller one that is probably the feed from the generator.
The large conduit seems to be large enough that it could contain the service wires from the meter which have looped down into the basement and back up again without actually terminating in the main panel. The box could then contain a service rated transfer switch which feeds back down into the basement to the main panel breaker.

This could potentially be completely code as long as the owner opens enough breakers to bring the load down to 100A before flipping the manual transfer switch.

2. The POCO service could be going down to the main breaker and the generator could be going to a backfed 100A breaker in the main panel with or without an interlock. Since you say the main panel is "not modified", I would have to say without an interlock. In that case the contents of the right box would just a breaker and not a transfer switch and the whole thing would be non-code and probably done without inspection.

So as kwired said, you need to know what is in the box, what is inside the main panel behind the cover, or what wires are in the two conduits. The difference among the possibilities is huge.

PS: There is only one service. The generator is a supply and may or may not be an SDS. If the outside switch is in fact a transfer switch, it may be a single service disconnecting means and the main panel breaker is not the service disconnect. But the service wiring may have gone too far into and back out of the house before it hit the first disconnect.
Where is/are the ground-neutral bond(s)?

 

[ActionDave]

I can't tell anything from that picture. As far as the whole house having 100A breaker for the generator, that's not a problem unless there is something hokey with the whole set up.

 

[Greg1707]

further information

further information

Thanks for the comments. I was called to this house to correct a "double tapped" breaker. The panel had no modifications to accommodate a generator. The homeowner told me the generator was installed ten years ago under some program offered by Dominion Power. This is a house in Northern Virginia. The photo to me looks like the box to the right of the meter has two conduits running underground to the generator. The larger conduit is for the power and the smaller for control wiring. I think this box is wired to be between the meter and the main panel.

This setup is different than the two setups we typically see today: critical circuit transfer switch or service rated whole house switch with technology to shed loads.

 

[kwired]

PS: There is only one service. The generator is a supply and may or may not be an SDS. If the outside switch is in fact a transfer switch, it may be a single service disconnecting means and the main panel breaker is not the service disconnect. But the service wiring may have gone too far into and back out of the house before it hit the first disconnect.
Where is/are the ground-neutral bond(s)?

When I said there may be more than one service, I meant the unit shown in the photo may be one and the original panel is the other. Really depends on just what is there we can not see.

Thanks for the comments. I was called to this house to correct a "double tapped" breaker. The panel had no modifications to accommodate a generator. The homeowner told me the generator was installed ten years ago under some program offered by Dominion Power. This is a house in Northern Virginia. The photo to me looks like the box to the right of the meter has two conduits running underground to the generator. The larger conduit is for the power and the smaller for control wiring. I think this box is wired to be between the meter and the main panel.

This setup is different than the two setups we typically see today: critical circuit transfer switch or service rated whole house switch with technology to shed loads.

If there is control wiring to generator then this is likely an ATS - the breaker we see under the clear cover is maybe a service disconnect ahead of the ATS.

If that is the case the biggest issues are if they ran line(service) and load (non service) conductors through the nipple to the meter socket, if they ran an additional EGC to the old service panel and separated neutrals from equipment grounding conductors, removed the bonding jumper from old panel, and moved grounding electrode conductor to the new service equipment.

I am guessing not all of this was done as it looks like the SE cable below the meter is likely the feed to the inside panel and it appears to be 3 wire cable and not 4 wire cable.

 

[Jube]

Greg, it appears that you have a collar mount transfer switch. The power is actually transferred in the collar that is mounted behind the meter. The 100 amp breaker is only for the generator feed, the utility power goes straight thru to the house panel. The reason for the seu and not ser cable is the manufacture claims the netral is not interrupted at meter and routed thru transfer switch so no 4-wire needed. I don't know where you are located but the ones I have seen and installed were provided by Rappahanock electric co-op, which is in the Fredericksburg area. It's been a few years since I installed one of these, I remember not liking them but I don't remember why! Good luck, Jube.