L6-20P -> L6-30R

Rob Seastrom rs at seastrom.com
Wed Mar 19 13:32:13 UTC 2014


Alex Rubenstein <alex at corp.nac.net> writes:

> But my point remains. Appliance/load wire size is often, and many
> times smaller than the ampacity of the circuit.
>
> Heck, how many times have you plugged in a 14 gauge extension cord
> to a 5-20R?

I do this all the time.  In (all our) defense, lamp cord is the
closest thing to conductors in free air that most people will ever run
into, and although the insulation isn't high temperature stuff, the
heat buildup isn't the same as a few dozen THHN conductors in EMT.

If you want something that will make your head explode a little (until
you think it through and realize that "ampacity" is just another way
of expressing "i^2r losses plus dissipation rate), read NEC table
630.11(A), and then 630.12(A) and noodle on just how skinny a wire you
can use for hooking up a (home, low duty cycle) welder that's
breakered at 50 amps.  12 AWG anyone?

-r




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