The Hurdy Gurdy Man wrote in
news:MAYGf.17404$j07.12317@trnddc04:


If you're running a motor load at the end of a length of wire, it
seems easy enough to use a table or a program to determine the
appropriate gauge of wire to use to keep the voltage drop within a
desired range. But how do you calculate what to use if the wire
gauges change midway through the run? Here's an example. Let's say
you have a three horsepower, 240 volt, single phase motor at the end
of 300 feet of 10 gauge wire. From what I have come up with when
plugging those values into some of the online voltage drop
calculators, that's pretty much the maximum you'd want to do in order
to keep below a 5% voltage drop. But what if you have 200 feet of
wire leading up to the point where that 300 foot run of 10 gauge
begins? It's easy enough if you were using 10 gauge the whole way,
but what if you had 200 feet of 2 gauge, then 300 feet of 10 gauge?
How does that change things?


The voltage drop is additive. Use the calculator to calculate the 200 ft
run of 2 guage, then the 300 ft of 10 gauge, add them together and you
get your voltage drop along the entire run. Might want to add a percent
or two for possible connection losses.

--
Anthony

You can't 'idiot proof' anything....every time you try, they just make
better idiots.

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