Largest Breaker in panel

Status
Not open for further replies.
unless you need it as a disconnecting means, why not use a sub-feed lug kit. less expensive
 
I would check the panel door and see what it states. Some panels only allow 125 amps on a post. In that case you cannot even put a 90 amp breaker and a 40 amp breaker opposite each other.
 
augie47 said:
unless you need it as a disconnecting means, why not use a sub-feed lug kit. less expensive
Click to expand...


In Square D parlance, sub-feed lugs are only available on the line side of main breakers or as part of main lug only arrangements. On the load side of a main breaker you can only have Through-Feed Lugs.

Panels, from most manufacturers, with Through Feed Lugs almost always have lower SCCR. I think it has to do with UL testing procedures.

Just to add to confusion Square D calls all separately mounted large branch breaker (those not connected like normal branches) ' sub-feed breakers' , even if they are after a main device.
 
jim dungar said:


In Square D parlance, sub-feed lugs are only available on the line side of main breakers or as part of main lug only arrangements. On the load side of a main breaker you can only have Through-Feed Lugs.

Panels, from most manufacturers, with Through Feed Lugs almost always have lower SCCR. I think it has to do with UL testing procedures.

Just to add to confusion Square D calls all separately mounted large branch breaker (those not connected like normal branches) ' sub-feed breakers' , even if they are after a main device.
Click to expand...

as if it wasn't confusing enough :)
(I just went thru that and learned, in my case, they don't (or didn't) series rate the panels sub-feed breakers. Glad you are here to shed light,.)
 
jeff48356 said:
I've never seen a standard-size breaker greater than 125 amps.
Click to expand...

jim dungar said:
Define standard-size.

For "load centers" you don't ordinarily plug on branch breakers larger than 125 amps, there may be some over 125 amps available that take up more than one space per "pole" though.

If you are around I-line or similar panels much at all, 400 and 600 amp breakers may be considered to some to be "standard breakers" yet a 15 amp breaker will plug onto the same bus.



In Square D parlance, sub-feed lugs are only available on the line side of main breakers or as part of main lug only arrangements. On the load side of a main breaker you can only have Through-Feed Lugs.

Panels, from most manufacturers, with Through Feed Lugs almost always have lower SCCR. I think it has to do with UL testing procedures.

Just to add to confusion Square D calls all separately mounted large branch breaker (those not connected like normal branches) ' sub-feed breakers' , even if they are after a main device.
Click to expand...

I may be wrong but with Square D isn't "feed through lugs" typically mounted on the opposite end and typically about same thing as the lugs on the supply end of a "main lugs" bus? And what they call "sub feed lugs" is typically a bolt on/plug on unit that goes in place of a branch breaker but has no switch or overcurrent protection?
 
kwired said:
I may be wrong but with Square D isn't "feed through lugs" typically mounted on the opposite end and typically about same thing as the lugs on the supply end of a "main lugs" bus? And what they call "sub feed lugs" is typically a bolt on/plug on unit that goes in place of a branch breaker but has no switch or overcurrent protection?
Click to expand...

I am not sure if there is any official standard terminology, but I pretty much agree with you: "feed thru lugs" usually refers to lugs on the opposite end of the bus as the supply. "Sub feed lugs" usually refer to lugs on the same end as the supply (usually just a double port lug for smaller panelboards). Then there are the plug on/bolt on kits you mention, like this:

https://www.homedepot.com/p/Siemens-Sub-Feed-Lugs-for-150A-225A-Load-Centers-ECLK2225/207050664

I guess those are also called "sub feed lugs" sometimes I hear them called "sub feed terminal blocks" or "sub feed kits" or similar.
 
electrofelon said:
I am not sure if there is any official standard terminology, but I pretty much agree with you: "feed thru lugs" usually refers to lugs on the opposite end of the bus as the supply. "Sub feed lugs" usually refer to lugs on the same end as the supply (usually just a double port lug for smaller panelboards). Then there are the plug on/bolt on kits you mention, like this:

https://www.homedepot.com/p/Siemens-Sub-Feed-Lugs-for-150A-225A-Load-Centers-ECLK2225/207050664

I guess those are also called "sub feed lugs" sometimes I hear them called "sub feed terminal blocks" or "sub feed kits" or similar.
Click to expand...
My comment was referring to Square D common practices. I have ordered panels (real panels not "loadcenters") where you need to specify "feed through lugs" if you want them, and it not only puts lugs on the opposite end of the supply end of the bus, but it usually also means additional hardware and extra cabinet length to allow for wire bending space.

I have also ordered "feed through lugs" for certain panelboards - which was a unit that plugged onto space that otherwise would be used by branch breakers.

One particular I line panel I once used had no main breaker or main lugs. You backfed a breaker if you needed a main breaker or backfed a "subfeed lugs" assembly if you did not need a main breaker.

Other manufacturers can use whatever names they wish, that is just what I observed that Square D seems to call these items.
 
Status
Not open for further replies.
Top