250 Volt Receptacles

[steve66]

Looking at 250 Volt receptacle configurations (say NEMA 6, for example), do these have to be connected to a 240V source, or can they be connected to a 208V transformer?

Steve

 

[John Valdes]

The 250 volt labeling on NEMA rated plugs and recepatacles is for okay 208 through 250 volts.
I would need more info about the XFMR situation, to give you any specifics.

 

[steve66]

How does the guy plugging in his equipment know if he is getting 208 or 240? Or do I assume any plug-in equipment is dual rated?

This is in the design phase, so I am free to specify any transformer I want.

Thanks:
Steve

 

[charlie b]

How does the guy plugging in his equipment know if he is getting 208 or 240?

He could look at the power panel or at the one line diagram. But if this is a facility to which contractors will bring their own equipment, it is incumbent on them to verify that the available power source will work with the equipment they bring to the site. If you wish, you could specify that a label shall be placed at the receptacle, just to make it easier for future contractors. But I don?t think anything would require you to do so.

Or do I assume any plug-in equipment is dual rated?

I think not. If you are specifying the equipment (i.e., others will not be bringing their own equipment to plug into this outlet), then you could include a dual-rating in the specs.

This is in the design phase, so I am free to specify any transformer I want.

Again, I do not know whether you need be concerned about others bringing their own equipment to the site. If not, then pick your own choice of transformer, and write that voltage rating into the specs for the equipment.

 

[steve66]

Thanks Charlie.

These are for receptacles in a parking lot. The idea is that once in a while they have concerts, or venders who bring in trailers that plug in. So I have no control over what is plugged into these outlets. The receptacles themselves will be on power pedestals identical to the ones used at RV Parks and Campgrounds.

Steve

 

[zbang]

As someone who's often using these outlets.. I seldom trust the voltage, but in most places I assume it'll be 120/208. It's kind of rare to find 120/240 in such commerial environments.

OTOH, if it's cheap/easy to supply 120/240, go for it. That'll make the food vendor's heaters work properly.

Consider using 50a RV/"california" recepticals, they're common on rental power distros. BTW, you'd want L14's not L6's so you get a neutral to go with the hot legs. Not so useful without the N.