StitzieJ
Member
- Location
- Harrisburg, PA
Is it within NEC code to backfeed a 125 amp main lug load center with a 60 amp circuit breaker? Doing this to lower the amperage at which the panel disconnects from the feeder, as the specifications call for.
Backfeeding
- Thread starter StitzieJ
- Start date
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publicgood
Senior Member
- Location
- WI, USA
Your use of the term backfeed is broad.
Maybe this answers your underlying question: If you have a 150A MLO load center, you may choose to serve it with a 60A feeder breaker. The associated feeder may remain 150A ampacity or be changed out to match the reduced load following NEC requirements for feeder sizing. If the load center is the main panel in a residential application, you should review the code requirements for minimum service size. You may also pay close attention to any branch motor circuits or transformer feeders for in-rush now that you have smaller OCPD upstream. KAIC rating of the changed out breaker should meet minimum fault current also without the requirement for series rating.
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Maybe this answers your underlying question: If you have a 150A MLO load center, you may choose to serve it with a 60A feeder breaker. The associated feeder may remain 150A ampacity or be changed out to match the reduced load following NEC requirements for feeder sizing. If the load center is the main panel in a residential application, you should review the code requirements for minimum service size. You may also pay close attention to any branch motor circuits or transformer feeders for in-rush now that you have smaller OCPD upstream. KAIC rating of the changed out breaker should meet minimum fault current also without the requirement for series rating.
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- Location
- Chapel Hill, NC
- Occupation
- Retired Electrical Contractor
Yes you can backfeed a 125 maiin lug panel with a 60 amp main but you must use a hold down kit
Yes.
With the proper hold down kit that is if the 60 amp breaker will be installed in that particular panel.
JAP>
Coppersmith
Senior Member
- Location
- Tampa, FL, USA
- Occupation
- Electrical Contractor
125 amp is the maximum capacity of the load center. You can backfeed it with any size breaker up to 125 amps. I frequently install 125 amp subpanels with 60 amp backfeed breakers because this is an economical combination.
And as was mentioned above, the hold down kit is required. (It's like 3 bucks on an Eaton panel
)
kwired
Electron manager
- Location
- NE Nebraska
- Occupation
- EC
Factory installed main breakers in stocked items are typically limited to 100, 125, 150, 200, 225 amps on your usual "loadcenters". Basic bus structures are 125 amp and 225 amp, sometimes 150 amp. Really small panels (2-6 slots) may have 40 or 70 amp bus.
If you want any other combination you need to get one with a bus equal or higher then your need and necessary breaker.
"convertible mains" panels may have wide variety of available main breakers, but you still mostly only find the ones mentioned above as the only that are already installed in stocked items.
Commercial panelboards - you usually order exactly what you want - could be factory assembled, or they may send you all the parts and you field assemble it.
If you want any other combination you need to get one with a bus equal or higher then your need and necessary breaker.
"convertible mains" panels may have wide variety of available main breakers, but you still mostly only find the ones mentioned above as the only that are already installed in stocked items.
Commercial panelboards - you usually order exactly what you want - could be factory assembled, or they may send you all the parts and you field assemble it.
ggunn
PE (Electrical), NABCEP certified
- Location
- Austin, TX, USA
- Occupation
- Consulting Electrical Engineer - Photovoltaic Systems
It depends. Is it a subpanel or a main? Is there protection elsewhere for the busbars in that panel? Is the backfeed from a utility interactive inverter or a generator?
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