OCPD on welding receptacle

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mull982

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When installing a welding receptacle must the receptacle rating be smaller than the OCPD upstream feeding the receptacle.

In other words If I had a 100A breaker feeding out to a 100A non-fused disconnect which was connected to a 60A welding receptacle is this incorrect? Should the welding receptacle be a 100A rated receptacle or the breaker changed to a 60A?

Does the same apply for convenience receptacles?
 
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Cold Fusion

Senior Member
Location
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mull982 said:
When installing a welding receptacle must the receptacle rating be smaller than the OCPD upstream feeding the receptacle.

In other words If I had a 100A breaker feeding out to a 100A non-fused disconnect which was connected to a 60A welding receptacle is this incorrect? Should the welding receptacle be a 100A rated receptacle or the breaker changed to a 60A?

Does the same apply for convenience receptacles?
Click to expand...
Would these "convenience receptacles" be 480V, 60A, 3ph, 4W receptacles scattered around the plant - rarely used for welding machines now that the plant is built, but regularly used for temporary power for small projects or portable equipment?

cf
 
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suemarkp

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Kent, WA
Occupation
Retired Engineer
Also see 210.21(B)(1) Exception 2. I'd say OK for welders (but you may have to label the receptacles as "welders only"), but not general use convenience receptacles.
 
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mull982

Senior Member
suemarkp said:
Also see 210.21(B)(1) Exception 2. I'd say OK for welders (but you may have to label the receptacles as "welders only"), but not general use convenience receptacles.
Click to expand...

So if we look at table 630.11(A) and from the welders nameplate determine that the brance circuit amapcity only needs to be 50A then this 60A receptacle will be fine due to the fact that 210.21(B)(1)exception 2 says the recpt rating only needs to be greater than the ampacity calculated in 630.11. This would not matter then what the size of the branch circuit or OCPD is? In this case its #2 with a 100A breaker.

However for all other general purpose recpt's the recpt rating must be no smaller then the circuits ampere rating which in this case is 100A based on the circuit breaker. Is it still 100A even though the circuits ampere rating of a #2 is 115A?
 
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