I have a Cutler Hammer PRL1a main panel which I just found out that the max amps for a 2-pole breaker is 100amps. I need to power a storage container which has a 125 amp sub panel. Is there any code against me using the 2-pole 100 amp breaker to feed the 125 amp sub panel or does it have to be the same amperage?
Breaker question
- Thread starter hl53us
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kwired
Electron manager
- Location
- NE Nebraska
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- EC
You can feed a 1000 amp panel with a 15 amp breaker if you wanted to, more important question is what is your calculated load you need to be able to handle?
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- San Francisco Bay Area, CA, USA
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- Electrical Engineer
When a panel is called a "125A panel", that's just the maximum amperage you can load it to safely. There is no code against using it for something smaller, just not larger.
If your load at the storage container is over 80A continuous you may have a problem though.
Right on, my thoughts exactly. More times that not it is about reading through the lines. The OP omitted the reason for the 125a requirement. The last subpanel that I installed was a 125a load center with a 100a main breaker. But I only needed it for a 50a. I sized the feeder for 50a and sized the feeder breaker for a 50a.max load. Since I like a main breaker disconnect in my subpanels the 100a main breaker simply becomes a main disconnect.
kwired
Electron manager
- Location
- NE Nebraska
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- EC
OP has a 125 amp panel because that is standard bus size.
Say his calculated load was 55 amps - most panelboard makers only have 125 to choose from so that is what you use though he could supply it with 55 amp conductor and a 60 amp overcurrent device. All the manufacturers have panels with 100 amp main breakers installed - but very likely they have same bus design as other panels rated 125 amps.
Say his calculated load was 55 amps - most panelboard makers only have 125 to choose from so that is what you use though he could supply it with 55 amp conductor and a 60 amp overcurrent device. All the manufacturers have panels with 100 amp main breakers installed - but very likely they have same bus design as other panels rated 125 amps.
Michael15956
Senior Member
- Location
- NE Ohio
That install needs 4 wires, not 3 wires.
jumper
Senior Member
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- 3 Hr 2 Min from Winged Horses
EGC could be metallic conduit.
Michael15956
Senior Member
- Location
- NE Ohio
Yes, your are right, good catch.
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