On Sep 4, 2:24 pm, Jim Stewart wrote:
The business had a little extra cash before tax
time so my wife let me buy a Thermal Arc 185 TIG
welder.

I sorted out the plug/socket and installed an
outlet for the unit. I also want to fabricate
a 20' extension cord for the unit, and that's
where I got confused.

The welder specs call out 38 amps/240 volts as
the max current draw. The welder comes with a
line cord with 12 gauge conductors with a 50
ampere plug on the end. Anyone see the apparent
contradiction here?

I installed a 50 ampere breaker, the called-out
50 ampere socket, and 50 ampere-rated conductors
between the two. Should be no issue there.

The problem is the 20 foot extension cord. 8
or even 10 gauge portable cordage would seem
to be a waste given the 12 gauge cord on the
unit. OTOH, there's just something wrong about
putting a 25 amp cable on a 50 amp breaker running
to a 38 amp load.

what was the duty cycle of the unit at max? probably 20%

so for 2 minutes out of 10 the 12 gauge cord has to carry a 38 amp
load

then the cable has eight minutes to cool down

What is the cost of the cable compared to the cost of the machine?

is it really worth saving the 20 dollars on the length of the
extension cord to use 12 instead of 8 Gauge? comapred to the 1500 to
2000 dollar machine and the even remote chance of a fire hazard?

In fact if youre feeling extra cautious cut the breaker down to 40
amps and you should still never manage to pop it.

For what youre saving on cable the safety seems a better choice