DC & 400Hz Power Receptacles

[nc5p]

We are setting up lab facilities for testing power supplies and ruggedized equipment that are used in aviation, ground vehicles, and ships. (military applications) This equipment runs on a variety of power including 28 VDC, 120/208y 3-phase 400 Hz, in addition to 120V 60 Hz. Our 28 volts and 400 Hz comes from converters. All three power systems need to be routed through filters into an EMI test chamber. I am looking at the chamber's interior wiring and need to select receptacles that will allow connection to appropriate power. For the 120 volt that is standard straight blade. For the 120/208 400 Hz I figured on using a 20A twist lock NEMA type. Now for the 28V, the supply will operate up to 35 Amps so I was considering using a 30A twist lock type but don't know if NEC allows DC power on a NEMA style receptacle. Some of the Non-NEMA types carry a DC rating. I figured Non-NEMA couldn't be used in new work?

Can I use a standard NEMA locking receptacle provided no other receptacle in the facility uses that style for another voltage? If not, what about the Hubbell Variload receptacles? They have unique center pins for different voltage use. Anybody here installed these?

 

[LarryFine]

Anybody here installed these?

It just so happens that I worked on such a job way back when I was a little helper. We used a three-compartment metal duct system that we mounted to the wall horizontally and had to use conduit under the floor at doorways.

I don't recall the receptacle configs, except you're correct about the duplexes (we used 20a T-slots). I do remember that the 28v and 3ph receptacles were single round-hole twist-locs, and the NEMA config was in the specs.

I believe that the customer will want a specific receptacle for each voltage. The equipment they need to power should already have specific power-cords they use. Check with the engineer or job head.