Breaker Frame Sizes between Manufacturers

[MrJLH]

Are breaker from sizes the same between manufacturers?

i.e. A "F" Frame Cuttler Hammer is the same size as a "F" Siemens.

Thanks

 

[petersonra]

I don't think there is any standardization of nomenclature between manufacturers as far as what they call a frame size. There might be some in the UL 489 standard but it would be based on ratings and not the manufacturers model number.

 

[Jraef]

It’s not even there in UL489.
Frame sizes were somewhat standardized eons ago when there were only a few mfrs and they WANTED people to be able to change out a competitor’s breaker with their own. But once short circuit interrupt ratings and listing/testing requirements standardized, that became virtually impossible anyway. Now it means something only within each manufacturer’s product line.

That said, breaker manufacturing is a very up-front design intense process that is expensive, but once done, breakers can be manufactured very cheaply (relative to the sell price) at high volumes. So a lot of mfrs make a particular frame size that they then sell in bulk to competitors to keep their volume up, resulting in an odd mashup of specific frames that do in fact physically interchange. But the brand-labelers retain the rights to the listings in their own gear. So even though a form of 100AF Siemens breaker is the same as the 100AF Eaton breaker (both are made at Eaton’s facility in the Dominican Republic), you cannot put the Eaton version into a Siemens panel or vice versa. It will physically fit, but you will be violating the listing of the panel.

 

[MrJLH]

It’s not even there in UL489.
Frame sizes were somewhat standardized eons ago when there were only a few mfrs and they WANTED people to be able to change out a competitor’s breaker with their own. But once short circuit interrupt ratings and listing/testing requirements standardized, that became virtually impossible anyway. Now it means something only within each manufacturer’s product line.

That said, breaker manufacturing is a very up-front design intense process that is expensive, but once done, breakers can be manufactured very cheaply (relative to the sell price) at high volumes. So a lot of mfrs make a particular frame size that they then sell in bulk to competitors to keep their volume up, resulting in an odd mashup of specific frames that do in fact physically interchange. But the brand-labelers retain the rights to the listings in their own gear. So even though a form of 100AF Siemens breaker is the same as the 100AF Eaton breaker (both are made at Eaton’s facility in the Dominican Republic), you cannot put the Eaton version into a Siemens panel or vice versa. It will physically fit, but you will be violating the listing of the panel.

Yeah found a gem this morning during some NETA testing. Found an old Siemens ITE 240 VAC rated breaker in a 480VAC service that feeds backup power to the control room.

Hopefully I an get something to fit. Bad part which could be a good thing is tis beaker is mounted in a spin top style enclosure. Ill check back in a few hours.

 

[Jraef]

Yeah found a gem this morning during some NETA testing. Found an old Siemens ITE 240 VAC rated breaker in a 480VAC service that feeds backup power to the control room.

Hopefully I an get something to fit. Bad part which could be a good thing is tis beaker is mounted in a spin top style enclosure. Ill check back in a few hours.

For the most part, Siemnes has never discontinued most of the old ITE breakers, you can still buy them.