[Beowulf] Quick question...

Larry Stewart larry.stewart at sicortex.com
Sat Mar 17 10:20:49 PDT 2007

Robert G. Brown wrote:
> As I'm working up a server room and some UPS's, a question arises.  The
> APC units we have have a different plug and current rating from the
> circuits in the wall.  In particular, we have L6-30R receptacles and the
> APC requires only 20A.  I had thought that it would be perfectly safe to
> replace an L5-20P with an L6-30P and plug a 2200 VA UPS into a 30 amp
> circuit, but the electrician who was doing some of the rewiring said "we
> can't do that" because "the 30A circuit breaker might not blow in time
> to protect" the 2200 VA device from damage in the event of an internal
> short.
> This argument seems quite senseless to me.  If this argument were
> correct we could never plug a 15 A device into a 20 A circuit, etc.  It
> would really simplify my life if I can just rehead the cable.  Do any of
> the electricity-savvy people here have any comments regarding the safety
> or legality of doing so?  I have always assumed that going up a size in
> circuit capacity is generally safe and legal...
> I'm planning to do the rewiring of cables today soon, so if you know
> something about his please respond "soon".
>    rgb
The code says that a single receptacle on a circuit must have a rating 
at least
as high as the circuit breaker, so you can't change the receptacles to 
unless you change the breakers too.

Here's an adapter that does what you want.


Counting labor, it might be cheaper than rewiring the cords.


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