4 POLE BREAKER ON 240 1Ø SERVICE

Status
Not open for further replies.
WA_Sparky

WA_Sparky

Electrical Engineer
Location
Vancouver, WA, Clark
Occupation
Electrical Engineer
Project I'm working on has the meter and main service disconnect (120/240V 1Ø service) out on the power pole on site. This panel serves (3) sub panel, (1) 200A 120/240 1Ø panel inside, (1) 125A 120/240V 1Ø sub panel on the same pole as service meter, and (1) 100A 120/240V 1Ø sub panel on a different pole.

The main service disconnect and the panel inside the building and the service disconnect both are using 4pole breakers as disconnects.

Can anyone explain why someone would use 4 pole disconnects? I remember running into this on a previous project with a generator that served multiple buildings due to multiple neutrals needing disconnected. Is 4p disconnect because the other loads on site arent connected to the buildings neutral/ground? I see why there would be a need for the 4p at the service but I cant wrap my head on why there would be a 4p disconnect for the Main on the panel inside?

Thanks,
 
G

ggunn

PE (Electrical), NABCEP certified
Location
Austin, TX, USA
Occupation
Electrical Engineer - Photovoltaic Systems
WA_Sparky said:
Project I'm working on has the meter and main service disconnect (120/240V 1Ø service) out on the power pole on site. This panel serves (3) sub panel, (1) 200A 120/240 1Ø panel inside, (1) 125A 120/240V 1Ø sub panel on the same pole as service meter, and (1) 100A 120/240V 1Ø sub panel on a different pole.

The main service disconnect and the panel inside the building and the service disconnect both are using 4pole breakers as disconnects.

Can anyone explain why someone would use 4 pole disconnects? I remember running into this on a previous project with a generator that served multiple buildings due to multiple neutrals needing disconnected. Is 4p disconnect because the other loads on site arent connected to the buildings neutral/ground? I see why there would be a need for the 4p at the service but I cant wrap my head on why there would be a 4p disconnect for the Main on the panel inside?

Thanks,
Click to expand...
I've seen a lot of those. Old GE, I believe.
 
Strombea

Strombea

Senior Member
Location
Prescott, Arizona, USA
If it's snapped onto the buss as a center feed it is because 1 buss space for each phase is not rated at 200amps, so they use 2 buss spaces and can get the rating. They also have to cross cross the phases to keep the phasing correct.

1634950181737.jpeg
 
N

norcal

Senior Member
Strombea said:
If it's snapped onto the buss as a center feed it is because 1 buss space for each phase is not rated at 200amps, so they use 2 buss spaces and can get the rating. They also have to cross cross the phases to keep the phasing correct.

View attachment 2558169
Click to expand...
They set the bus stabs to accommodate the breaker design, might have to get a photo of a scrap Cutler-Hammer CH bus showing how the factory set it up, ITE Imperial Corp., was the first to introduce the 4-pole wide breaker in the 1970's, GE, C-H, (as shown in the photo) & SQ D Homeline, have/had them also.
 
WA_Sparky

WA_Sparky

Electrical Engineer
Location
Vancouver, WA, Clark
Occupation
Electrical Engineer
norcal said:
They set the bus stabs to accommodate the breaker design, might have to get a photo of a scrap Cutler-Hammer CH bus showing how the factory set it up, ITE Imperial Corp., was the first to introduce the 4-pole wide breaker in the 1970's, GE, C-H, (as shown in the photo) & SQ D Homeline, have/had them also.
Click to expand...
Do you know if its possible for someone to use a 4 pole breaker to disconnect (2) 2p loads? Also do you know if its possible for a panel to have a split buss where a 4 pole breaker can be used, 2poles disconnect the left side and 2 poles disconnect the right side? I'm letting my imagination run here with trying to make sense of it so don't hesitate to shoot me down.

Thanks,
 
Status
Not open for further replies.
Top