20A Feeding 30A

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Mention it to the engineer and ask if that's what he really meant.

The breaker is feeding a multi-outlet assembly-- PDU or the like, I'm assuming, feeding everything in the rack.

>NON-CODE OPINION<-- I don't see an issue-- the 20A breaker will limit power fed to the PDU. If the PDU can handle more current, so much the better. I would expect that the wire between the 20A breaker and the 30A PDU must be sized for 30A.
 
horsegoer said:
Engineer shows a 208V 30A multi outlet assembly in IT rack fed from 20A breaker. Can't have that correct?
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I agree with you not permitted. If you have a 20 amp OCPD you can 20 amp conductors but for a multi-outlets you cannot use 30 amp devices.
Table 210.21(B)(3) Receptacle Ratings for Various Size Circuits lists 20 amp: either 15 or 20 amp receptacles. A single 30 amp receptacle on a 20 amp circuit would be permitted.

210.23 Permissible Loads, Multiple-Outlet Branch Circuits. In no case shall the load exceed the branch-circuit ampere
rating. A branch circuit supplying two or more outlets or receptacles shall supply only the loads specified according to its size
as specified in 210.23(A) through (D) and as summarized in 210.24 and Table 210.24.
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infinity said:
I agree with you not permitted. If you have a 20 amp OCPD you can 20 amp conductors but for a multi-outlets you cannot use 30 amp devices.
Table 210.21(B)(3) Receptacle Ratings for Various Size Circuits lists 20 amp: either 15 or 20 amp receptacles. A single 30 amp receptacle on a 20 amp circuit would be permitted.
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I'm a little lost..surprise..lol. The rack equip plugs into the MOA.
 
Can you provide more detail, especially how the MOA is connected to the power source? Is it cord and plug connected to a 30 amp single receptacle outlet fed by a 208 volt, 20 amp breaker?
 
Beaches EE said:
Can you provide more detail, especially how the MOA is connected to the power source? Is it cord and plug connected to a 30 amp single receptacle outlet fed by a 208 volt, 20 amp breaker?
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MOA is 208V 30A and fed from 20A 120V breaker. Obviously wrong. But I'm being told they will change the MOA to 20A. Still the voltage is wrong.
 
Sounds like you need to go back to the designer and figure out exactly what they want or just pull #10's and worry about it later.
 
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