Transfer switch feeding two panels

JMahaney

Member
Location
Mission
Occupation
Electrician
My customer is interested in having a whole home generator installed. They have an underground service that appears to be 400 or 300 A. Coming out of the meter can it feeds two panels one 100 amp panel and one 200 amp panel. What type of transfer switch would I need to feed the different panels. Would I need two transfer switches one 200 amp and one 100 amp?
 

LarryFine

Master Electrician Electric Contractor Richmond VA
Location
Henrico County, VA
Occupation
Electrical Contractor
JM, what is fed from the smaller panel?

Simply, yes, you'd need two ATSs, one acting as slave to the other, unless you'd rather rewire the service through a single 400a ATS.
 

JMahaney

Member
Location
Mission
Occupation
Electrician
JM, what is fed from the smaller panel?

Simply, yes, you'd need two ATSs, one acting as slave to the other, unless you'd rather rewire the service through a single 400a ATS.
Currently the meter feeds to both panels. 200 amp panel is for all their 240 V circuits the 100 amp is everything Single pole.
 

mopowr steve

Senior Member
Location
NW Ohio
Occupation
Electrical contractor
I just installed a 400 amp service rated ATS and it feeds two 200 amp panels. The load lugs on the transfer contractor even has lugs rated for 2 wires to be installed in them.
 

hillbilly1

Senior Member
Location
Atlanta,Ga
I just installed a 400 amp service rated ATS and it feeds two 200 amp panels. The load lugs on the transfer contractor even has lugs rated for 2 wires to be installed in them.
That’s the clean way to do it if you have a 400 amp main, unfortunately most residential services have two 150 or 200 MB’s, so it’s either rebuild the service, or use two transfer switches, which is usually easier.
 

mopowr steve

Senior Member
Location
NW Ohio
Occupation
Electrical contractor
That’s the clean way to do it if you have a 400 amp main, unfortunately most residential services have two 150 or 200 MB’s, so it’s either rebuild the service, or use two transfer switches, which is usually easier.
He said he has a 400 amp meterbase, probably really the 320. So all he needs is to put a 400 amp service rated transfer in line from his meterbase and panels.
 
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