[AT] Wire size for welder?? Help welder people!
Greg Hass
gkhass at avci.net
Tue Dec 7 21:00:24 PST 2004
John:
At the risk of being arrested by the "correct police", I will give what I
consider to be a "common sense" approach.
First of all, that amperage rating is only at the very top end of the usage
scale. I have a 150-amp wire welder and a 250-amp AC/DC stick welder. I
have been running both of them on a no.10 wire since I built the shop 10
years ago, and have never had a problem with the wires getting warm,
although I did use a 50-amp breaker (on the advice of a licensed
electrician) to take care of the sudden amperage jolt when striking an
arc. A big thing in my favor, however, is that my biggest run is 25 feet
from breaker box to welder. If you are already wired for a welder, I would
say go ahead and try it because if you are properly fused the worst that
could happen is that you would trip a breaker or blow a fuse. I would
guess that most of the welding jobs you would do would draw less than 30
amps anyhow. If you want to be correct, I would go with a no. 6 copper or
no. 4 aluminum entrance cable or Romex, whichever it's called in your
area. (Aluminum must always be one size bigger than copper to carry the
same amperage.) No. 8 copper would be sufficient for 45 amps, however in
our area it is next to impossible to find and costs more than no.6, which
is why I recommended going with the heavier cable. Just an opinion.
Greg Hass
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