L6-20P -> L6-30R

Staudinger, Malcolm mstaudinger at corp.earthlink.com
Wed Mar 19 16:48:12 UTC 2014

I recently bought a UPS with a 30R plug on it, and sat and tried for about 20 minutes to plug it into what I thought was a 30 socket. It was, in fact, a 20. They're similar enough that if you're looking at the ends you might be convinced that someone has bent a one of the ends of the plug funny, but no amount of trying will make them fit.


-----Original Message-----
From: Jay Ashworth [mailto:jra at baylink.com] 
Sent: Tuesday, March 18, 2014 4:12 PM
Subject: Re: L6-20P -> L6-30R

----- Original Message -----
> From: "Randy" <amps at djlab.com>

> I have a situation where a 208v/20A PDU (L6-20P) is supposedly hooked 
> to a 208v/30A circuit (L6-30R). Before I order the correct PDU's and 
> whip cords...sanity check...are connectors 'similar' enough that this 
> is possible (with force) or am I going to find we've actually got 
> L6-20R's on the provider side?

As it happens, the chart at 


suggests that the L6-20 and L6-30 are less different than you'd expect.

I *think* those are on different diameters, and a datacenter employee ought to friggin' know better... but I don't think it's 100% impossible that this has happened.  

If it did, you're gonna replace the plug anyway...

As long as there's a 20A breaker on the PDU, you're safe, if not within code.

-- jra
Jay R. Ashworth                  Baylink                       jra at baylink.com
Designer                     The Things I Think                       RFC 2100
Ashworth & Associates       http://www.bcp38.info          2000 Land Rover DII
St Petersburg FL USA      BCP38: Ask For It By Name!           +1 727 647 1274

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