Cutting bussing on a switchboard

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andyandy

Member
My guys recently installed a back up generator and ATS on an 800 amp 3 phase 120/208 volt switch board. The client only wanted certain loads from the switchboard to energize during an outage. So what they did is took all of the breakers for the loads to be served from the generator and moved them to the bottom of the bussing in the switchboard. They cut the bussing above said breakers and tapped it with conductors rated at 800 amps and ranto the ATS which is rated at 800 amps and then ran conductors rated at 800 amps from the ATS back to the other half of the cut bussing. The project was inspected and approved by the AHJ. recently another EC saw the installation and raised a huge red flag tto the client and AHJ saying the install is not correct. Does anyone have any opinions on this? Code sections?
 

ceb58

Senior Member
Location
Raeford, NC
My guys recently installed a back up generator and ATS on an 800 amp 3 phase 120/208 volt switch board. The client only wanted certain loads from the switchboard to energize during an outage. So what they did is took all of the breakers for the loads to be served from the generator and moved them to the bottom of the bussing in the switchboard. They cut the bussing above said breakers and tapped it with conductors rated at 800 amps and ranto the ATS which is rated at 800 amps and then ran conductors rated at 800 amps from the ATS back to the other half of the cut bussing. The project was inspected and approved by the AHJ. recently another EC saw the installation and raised a huge red flag tto the client and AHJ saying the install is not correct. Does anyone have any opinions on this? Code sections?

I hope I am following this cluster correctly. They are feeding the utility side of the ATS from the top portion of the buss bar. Then they are feeding the bottom portion from the t1 connections. So far you have a 110.3B violation
 

kwired

Electron manager
Location
NE Nebraska
Why not? Panels with contactor controlled split bus are not uncommon.

Never mind it does not really fit the description of what is not allowed as far as split bus goes.

In panelboards protected by three or more main circuit breakers or sets of fuses, the circuit breakers or sets of fuses shall not supply a second bus structure within the same panelboard assembly.


I would guess the modifications mentioned are not recommendations provided by the manufacturer of the equipment and would void any warranty as well as no longer let the equipment keep any listing it had.
 

paul

Senior Member
Location
Snohomish, WA
It sounds to me like it should have been listed in the field. I have modified equipment before and have had to have the UL inspector come out and put a new sticker on it after the mods.
 

kwired

Electron manager
Location
NE Nebraska
It sounds to me like it should have been listed in the field. I have modified equipment before and have had to have the UL inspector come out and put a new sticker on it after the mods.

After that is done is it truly UL listed or is it just inspected, approved, certified or whatever? Is it possible to get a listing for a one of a kind item? Some testing it may have to pass to receive a listing may be destructive to the product being tested.
 
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