4-pole circuit breaker.

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rrc14

Member
Location
Anchorage, AK
Occupation
Engineer
This is a 3-phase, 4-pole, 125A circuit-breaker, see attached. It is the main circuit breaker for a panelboard. Don't see many 4-pole circuit breakers. It has one pole for each phase, is the the fourth pole used to open the neutral? Why would a fourth pole be needed?

Thanks in advance!
 

Attachments

  • SE 4P-125A.pdf
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GoldDigger

Moderator
Staff member
Location
Placerville, CA, USA
Occupation
Retired PV System Designer
What tells you that this is a three-phase breaker?
Not super likely, but there would be four ungrounded in a five wire or four wire two phase (90 degree spacing) situation.
 

Jraef

Moderator
Staff member
Location
San Francisco Bay Area, CA, USA
Occupation
Electrical Engineer
It is a European style breaker, where it is not uncommon break the neutral.
In some situations in IEC countries breaking the neutral is required. As a result, some internationally based companies require breaking the neutral here in North America on their equipment, where it is not required but is not prohibited. The Semiconductor manufacturing industry is Ike that.
 

Russs57

Senior Member
Location
Miami, Florida, USA
Occupation
Maintenance Engineer
Looks like 2 poles are for 415 volt/125 amp and 2 poles are for 250 volt/20 amp.


Then click on product datasheet.


Hmmmmm, new replacement has all 4 poles at 415 volt/125 amp. Better be sure on model number. It may not be what you think!
 
Last edited:

GeorgeB

ElectroHydraulics engineer (retired)
Location
Greenville SC
Occupation
Retired
I looked at the datasheet for the (discontinued) product and its replacement. This appears to be a SWITCH, not a current sensitive circuit breaker. Can I just not read?
 

Jraef

Moderator
Staff member
Location
San Francisco Bay Area, CA, USA
Occupation
Electrical Engineer
Looks like 2 poles are for 415 volt/125 amp and 2 poles are for 250 volt/20 amp.


Then click on product datasheet.


Hmmmmm, new replacement has all 4 poles at 415 volt/125 amp. Better be sure on model number. It may not be what you think!
That’s a weird data sheet, makes no sense that a switch would have two different current ratings like that. My guess is that it is a typo in that the 20A 250V rating is DC, not AC, that would make more sense.
 
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