NEC 210.21(B)(1) - 40A CB feeding 30A Receptacle

[MtnTen79]

A 5.2kVA UPS is being installed to serve lab equipment. The manufacturer has stated that the unit comes with a 30A cord and plug that will require an L6-30R receptacle and should be fed from a 40A two-pole circuit breaker (208V, single-phase).

NEC 210.21(B)(1) states "A single receptacle installed on an individual branch circuit shall have an ampere rating not less than that of the branch circuit."

The manufacturer is calling for a 40A circuit breaker to feed a 30A receptacle, which appears to be in violation of NEC 210.21(B)(1).

Is anyone aware of any exceptions that may apply to a UPS, or similar equipment that could possibly allow what the manufacturer is suggesting?

Thank you for any help or explanation you can provide.

 

[jap]

Nope.

JAP>

 

[LarryFine]

Welcome to the forum.

You're correct. The UPS manufacturer's instructions do not supersede NEC requirements.

They need to come up with a compliant solution, like a smaller breaker or a larger receptacle.

 

[MtnTen79]

Thank you jap and LarryFine. I appreciate the responses.

 

[tom baker]

Welcome to the forum.

You're correct. The UPS manufacturer's instructions do not supersede NEC requirements.

They need to come up with a compliant solution, like a smaller breaker or a larger receptacle.

They may want the larger OCPD for UPS inrush on startup. It’s a mfg issue.

 

[MtnTen79]

They may want the larger OCPD for UPS inrush on startup. It’s a mfg issue.

UPS inrush is something the manufacturer's representative mentioned. If that is the case, I would assume they should provide the unit with a 50A, 6-50P plug, since I don't believe they make a 40A plug.

 

[infinity]

As an installer if it comes with a 30 amp plug it gets a 30 amp receptacle and a 30 amp OCPD. If it doesn't work that's the manufacturers problem.