2 150 amp service entrance breaker with Generac 22kw whole house generator

Status
Not open for further replies.
J

jeramiepluemer

Member
Location
Wisconsin
Occupation
Electrician
I am a new electrician and was wondering if anyone could help me with a problem I have. I have 2 150 amp main breaker in a large home. I can't get tech support to tell me how to do this but I was thinking that i would use 2 non service rated t switches and tie them together to get this job done. Does anyone work with Generac and could help me out.
 
Existing service. 100 amp breaker on 22kw. Normally we use 200 amp switch with load management per code for whole whole house. This has 2 150 amp main breakers. I am look at using 2 200 amp non service t switches or 2 ser switches because 400 amp t switch is 9 months out
 
Generac controls are kinda funky, but shouldn’t be a problem. Load shed may be a problem though, because the load would be split between the two transfer switches, so I don’t know if the Generac software would be able to control load shed with two switches instead of one. You could shed the larger non-critical loads using a relay that is de-energized when on generator power.
 
Seems most logical to me to just use one transfer switch serving one of the panels, and leave the other panel non generator. Move stuff around to put all your load shed stuff on the non generator panel.

I did one where there was a 600A service with 3 200 amp panels. It was dumb, 200A would be fine, so I moved non generator loads to one panel, and combined the other two and fed them from the transfer switch.
 
What is the calculated lad on the building? If it is under 200 amps with load shedding could you possible use one 200 amp transfer switch for both panels. Not sure if that would be compliant or not
 
Dennis Alwon said:
What is the calculated lad on the building? If it is under 200 amps with load shedding could you possible use one 200 amp transfer switch for both panels. Not sure if that would be compliant or not
Click to expand...
I have done that before, for some reason they thought they needed 2-150 panels, but load was minimal, as all lighting was LED, heating, cooking and water heating was gas. A/C load was not that big.
 
Dennis Alwon said:
What is the calculated lad on the building? If it is under 200 amps with load shedding could you possible use one 200 amp transfer switch for both panels. Not sure if that would be compliant or not
Click to expand...
From the picture, looks like he has a main breaker in each panel, should be doable if the load calcs work out.
 
jeramiepluemer said:
So use 2 non service t switches 200 amps. I dont understand.
Click to expand...
That's what I would do except use 150 amp switches. A 150 non service rated ATS on the load side of each150 amp service disco. Given the size of the service relative to the gen. size you likely will need some auto load shedding.
 
texie said:
That's what I would do except use 150 amp switches. A 150 non service rated ATS on the load side of each150 amp service disco. Given the size of the service relative to the gen. size you likely will need some auto load shedding.
Click to expand...
I agree but I have 2 200 am non service coming next month. Otherwise it is about 6 to 9 month. I though as long at there was a 150 amp somewhere it didnt matter or does is have to be before.
 
jeramiepluemer said:
I agree but I have 2 200 am non service coming next month. Otherwise it is about 6 to 9 month. I though as long at there was a 150 amp somewhere it didnt matter or does is have to be before.
Click to expand...
If there isn't a main breaker then it doesn't matter if it is 200 amp or 150 amp.
 
Dennis Alwon said:
If there isn't a main breaker then it doesn't matter if it is 200 amp or 150 amp.
Click to expand...
the only breakers are at the 2 panels and both are bonded so they both are mains. is that right. sorry i am so dumb. i just cant find anyone to help me. It is like I am bothering them because I am asking such dumb question. I dont care I swallow my pride and ask questions until i fully understand regardless what people think. so i am ok calling my self dumb
 
If you are using non service rated ATS the 200A rating is simply the bus rating as no overcurrent protection within the ATS. Thus if overcurrent protection is provided on line side of 150A and same at load ends and conductors sized for the rating of the overcurrent devices the 200A ATS should not be a problem.
jeramiepluemer said:
the only breakers are at the 2 panels and both are bonded so they both are mains. is that right. sorry i am so dumb. i just cant find anyone to help me. It is like I am bothering them because I am asking such dumb question. I dont care I swallow my pride and ask questions until i fully understand regardless what people think. so i am ok calling my self dumb
Click to expand...
If that is so, then the non service rated ATS would not be acceptable in that position within the supply circuit. Non service rated ATS requires overcurrent protect in advance of the ATS. If you put 150A fused disconnect (or breaker) ahead of the non service ATS it doesn't matter if the non service ATS is 200A or 400A, as long as the service does not exceed the ATS ratings.
 
jeramiepluemer said:
I agree but I have 2 200 am non service coming next month. Otherwise it is about 6 to 9 month. I though as long at there was a 150 amp somewhere it didnt matter or does is have to be before.
Click to expand...
The 200 amp non service ATSs are fine on the load side of your 150 amp service discos.
 
if breaker is in panel and i want to run 2 main panel would i just get 2 150 amp service rate panels and tie them in together. There is no load side to put non service rated t switch because breaker is build into panel. is this correct thinking
 
Status
Not open for further replies.
Top