Anthony J Lawrence
New member
- Location
- United States
I want to install a 1200A transfer switch in an existing panel. Is intercepting the main bus and rerouting the power through a transfer switch allowed or is a new service required?
Transfer switch installation.
- Thread starter Anthony J Lawrence
- Start date
- Status
- Location
- Placerville, CA, USA
- Occupation
- Retired PV System Designer
I do not understand just what you mean by intercepting the bus. If you are talking about physically cutting a bus and drilling it for new lug connections, that sounds like a really bad idea.
If the ATS is service rated and you can fit it into the panel, attaching the incoming service wires to it and its output to the bus feeding the load breakers, I do not see a problem with that.
If you will be attaching the ATS after the existing main breaker (somehow), then I guess that the ATS may not even have to be service rated.
My impression is that at 1200A you are talking about something a lot more substantial than a "load center", and a lot will depend on just what the architecture inside that panel is currently.
If the ATS is service rated and you can fit it into the panel, attaching the incoming service wires to it and its output to the bus feeding the load breakers, I do not see a problem with that.
If you will be attaching the ATS after the existing main breaker (somehow), then I guess that the ATS may not even have to be service rated.
My impression is that at 1200A you are talking about something a lot more substantial than a "load center", and a lot will depend on just what the architecture inside that panel is currently.
iceworm
Curmudgeon still using printed IEEE Color Books
- Location
- North of the 65 parallel
- Occupation
- EE (Field - as little design as possible)
3 phase? 480? 208?
And this "panel": Is this maybe a 2000A switchboard?
Consider attaching a oneline. That would help a lot.
ice
hbendillo
Senior Member
- Location
- South carolina
I had a project where there was an existing and very old (40 years) transfer switch built into an existing switchgear lineup. The owner wanted it and his generator replaced. The normal and load side of the transfer switch were bussed connections; One bus from normal side of transfer switch to a breaker in the normal section and another bus from the load side of the transfer switch to the emergency section of the switchgear. Emergency side of the transfer switch was cables from the generator.
The new transfer switch was shown installed on a nearby wall. We showed new cable connections from the existing normal power circuit breaker to the transfer switch, from the generator to the new transfer switch and from the new transfer switch to the emergency section of the switchgear. Actually the new cable connections were made in the old transfer switch section because we removed the old transfer switch.
We specified that an engineered solution be provided from a switchgear manufacturer or third party switchgear group. Busses had to be taken apart, modified and drilled for cable connections and busses supported and braced both mechanically and for short circuit. You have to make sure proper clearances between busses and cable lugs are maintained, insulation is not compromised, etc., etc.,
I cannot picture how you can put a 1200 amp transfer switch in an existing "panel"? Is this a switchboard or what? Why would you do that rather than install a 1200 amp breaker in the panel and feed a separate transfer switch?
The new transfer switch was shown installed on a nearby wall. We showed new cable connections from the existing normal power circuit breaker to the transfer switch, from the generator to the new transfer switch and from the new transfer switch to the emergency section of the switchgear. Actually the new cable connections were made in the old transfer switch section because we removed the old transfer switch.
We specified that an engineered solution be provided from a switchgear manufacturer or third party switchgear group. Busses had to be taken apart, modified and drilled for cable connections and busses supported and braced both mechanically and for short circuit. You have to make sure proper clearances between busses and cable lugs are maintained, insulation is not compromised, etc., etc.,
I cannot picture how you can put a 1200 amp transfer switch in an existing "panel"? Is this a switchboard or what? Why would you do that rather than install a 1200 amp breaker in the panel and feed a separate transfer switch?
- Status