Generator Transfer Switch in existing installation

[johnsciolino]

We have a customer that wants a whole house generator on a 400amp service 1ph 3w. Currently the main breaker is inside and only the meter is outside.
We can install a service rated transfer switch outside and slide the meter can over but the existing conductors are 3wire. I believe by code, since the main will now be outside (even though the breaker is existing inside), the service cable would have to be changed to 4wire?
The dilemma is this:
Since the house is 2 story it would be impossible to install a new cable without defacing the inside and outside of house. We are not talking about minor holes, this would be a major undertaking.
Maybe the "authority having jurisdiction" could make an exception??

 

[fmtjfw]

Can you put the transfer switch inside? If so get one that is service entrance rated. This may solve you 3/4 wire problem.

 

[electrofelon]

I just looked at one of these over the weekend. This setup was a 230.40 ex #2 service (2 200 amp main breaker panels). We are getting a 200 amp transfer switch and hooking it up between one of the panels and the meter and making that panel into a sub. We are mounting the transfer switch inside since it must be grouped with the other service disconnect. Is your setup like this or is there a single 400 main? The latter would be unusual as it is much cheaper and more convenient to use 2 -200's grouped. Whether or not the service disconnect is outside has nothing to do with the how many wires the feeder between it and the next panel must be. If the transfer switch is your service disconnect, everything downstream must be supplied by a four wire feeder and that panel must not be bonded (separate neutrals and grounds). I assume the meter is back to back - or close to it - to the panel so why do you think it will be so difficult to upgrade the feeder?

 

[johnsciolino]

Its a single 400amp service, existing main is not easily accessible on the inside of house. Installing ATS inside will not solve the issue since I would still need to tear up ceilings in a bedroom, kitchen and hallway. This is what I'm trying to avoid, the homeowner does not want to replace several ceilings.
The meter/panel location is simply not on the "garage side" of the house.

 

[fmtjfw]

It appears you can not make a code compliant installation without running a grounding conductor to the old main service panel or locate a service-rated transfer switch at the location of the old main service panel. And if you locate the transfer switch at the old main service panel you need to run conductors along the same path for the service to the generator.

The words are plain in the code about sub panel grounding.

Sorry.