RE: [CAD_CAM_EDM_DRO] Wire size question...

Jan,

Believe me, this is not meant as a criticism (you know more electronics in
your little finger than I'll ever learn), but an observation based on a
background of being a master electrician. Unless there is some unique
characteristic of a power supply that I'm not taking into account:

The National Electric Code (which is ultra-conservative because it is
written by the Insurance Underwriters) and the NYC Electric Code (written by
people who make the insurance underwriters look liberal) say that #10 wire
size is suitable for carrying 30 amperes 100% duty cycle when installed in
conduit within walls (where the heat created will be retained).

Why would you feel hesitant about using it on a free air application (which
normally allows you to drop to a smaller wire size (think extension cord
wire gauge vs. house wiring wire gauge - not many people use a #12 awg
extension cord for a portable tool which draws 15 amps). Especially on a
short piece (30cm), the #10 awg is technically overkill, but shouldn't be a
problem. Going to #8 awg, my mean changing lugs, and other stuff for no
particular benefit that I can see.

If I've got this wrong, I'm always willing to learn.

Jeff


-----Original Message-----
From: JanRwl@... [mailto:JanRwl@...]
Sent: Wednesday, April 06, 2005 11:59 PM
To: CAD_CAM_EDM_DRO@yahoogroups.com
Subject: Re: [CAD_CAM_EDM_DRO] Wire size question...


In a message dated 4/6/2005 7:57:39 P.M. Central Daylight Time,
loudcouture2003@... writes:

I am building my power supply and i have a simple question, what size (AWG)
of wire should i use for 30 amps for about 30cm?<< If you mean "lead wires"
from the PS to the load, then #8 is about right.
If the load is "30 A. max., intermittent", #10 might do for such a short
run.
Lotsa luck! Jan Rowland






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