L6-20P -> L6-30R

Jeremy Bresley brez at brezworks.com
Wed Mar 19 02:34:24 UTC 2014

On 3/18/2014 6:11 PM, Jay Ashworth wrote:
> 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
>    http://www.stayonline.com/reference-nema-locking.aspx
> 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.
 From experience with some electricians who couldn't follow simple 
written instructions, it is physically possible to put an L6-20 plug 
into an L6-30 receptacle.  But it won't lock into place.  Beyond all the 
other reasons it's not recommended, the slightest bump of the cable will 
likely knock it loose causing whatever is on there to drop.  (Cue 
electricans knocking the production 6506E's offline 3 times in 20 
minutes while they were replacing the breakers and the supposedly 
redundant power cords...)

If you can unplug it to look, every one I've ever seen has had the 
voltage and amperage clearly molded into the face of it.

Jeremy "TheBrez" Bresley
brez at brezworks.com

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