L21-30R rating / UL 498

[MIEngineer]

All,

Does anyone have access to UL 498? I am interested in the testing for an L21-30R (208Y/120V, 3 ph). We have a testing lab that would like to have 240D/120, 3 ph, available to plug equipment into. There is no standard NEMA configuration that supports this so I am wondering if an L21-30R would work or if I would be required to have a L22-30R(480Y/277V, 3 ph) installed for this purpose due to the higher L-L and L-N voltage.

thanks as always.

 

[Dennis Alwon]

There is some info available online so do a search. I got this site. There is also the UL site

 

[MIEngineer]

Thanks for the link. Basically I'm trying to be cheap and avoid the $800 cost to puchase the standard for this single question.

 

[Dennis Alwon]

Thanks for the link. Basically I'm trying to be cheap and avoid the $800 cost to puchase the standard for this single question.

I wish I could help. I have the UL white book but that won't help. Someone may have it-- be patient.

 

[winnie]

I would suggest contacting a couple of device manufacturers to get information on the actual voltage rating of the device, as opposed to the voltage associated with that particular NEMA configuration.

See for example:
http://www.hubbell-canada.com/wiring/bryant/pdf/h/h46.pdf
where the dimensions (and seemingly terminal spacings) of the 208/120, 480/277 and 600/347 devices are all the same.

My (not referenced and not to be depended upon) understanding is that all of these devices are all built to essentially the same insulation level, and that the only difference is the _layout_ and _shape_ of the pins.

I'm pretty sure that the only code requirement is that you use _different_ configurations for the different voltages available in a facility. As long as you don't have 208/120 on L21-30 elsewhere, I believe you are fine with 240/120 on an L21-30.

-Jon

 

[wireguru]

for this application, I wouldnt use L21-30 -what if someone plugged equipment into it that expected 120v L-N on the high leg phase?

I would use the hubbell variload twistlocks. Its a 30 amp 4P5W 250v non nema twistlock designed for industrial use when the circuit rating doesnt match whats available on the nema chart. HBL45115 is a part number for one of the plugs to get you started in selecting them.

 

[MIEngineer]

Thanks all for the replies. It seems very easy now to see that having multiple voltages in the site (right next to each other) with the same receptacle could cause potential problems. I will look at the options presented.

Once again thank you.