600V NEMA plug

[sevlander]

Does the NEC or any other code restrict the use of a 600V AC rated NEMA plug or receptacle to supply 480V equipment if there is no source of 600V on the site? We have a customer who's 480V machines have 600V metal shrouded twistlock plugs presently being used. They are moving to a new facility that also does not have a 600V source. Will these plugs need to be changed to a 480V plugs in the new facility to pass inspection? The facility has in house maintenance that services the equipment. They do also have 480v twistlocks such as L16-20 also installed on smaller load equipment that makes it somewhat confusing.Thanks.

 

[LarryFine]

Te voltage rating is a maximum, so it shouldn't be an issue.

 

[winnie]

IMHO the NEMA configuration is not mandated by code. NEMA configurations are also a 'best practice' in order to prevent confusion.

IMHO a 600V plug on a device designed for 480V is a bad idea, but would not violate code. Further it would be reasonable for a device which can function both at 480V or 600V.

However my understanding is that code requires receptacles of different voltage have different configurations, but that the particular configuration is not mandated.

Thus I see no problem using L17 or L20 devices at 480V, as long as the same configuration is not used for 600V anywhere in the facility. But using L17 for 480V in one room and 600V in another room is a violation.

I disagree with Larry on one point: the NEMA configuration is _not_ the voltage rating of the plug or receptacle; it is the voltage indicated by that pin configuration. Many (but not all) manufacturers make all of their NEMA devices with a 600V rating, even those with a lower voltage configuration and label. You need to check the datasheet.

-Jon