[Public-List] Rewiring

[gregr at nethere.com]

John and I have a few differences of opinion here but he does allude to a
couple of important points about using conduit.
1. You shouldn't "Fill" it more than 40%.
2. Take the twist out of your wire before pulling it by laying it out
straight. It helps to put the spool on rod like one does for replacing line
on fishing reel. That way the wire comes off correctly. If you let the
spool lay on its side the wire comes off twisted.

Exceptions:

1. I'll guess that we use our Albergs differently. My girlfriend and I are
full time live-a-boards. I put in five AC outlets and that seems to be
about right for us. Yes, we could use inverter(s) off the 12V system but I
don't see the point of paying for the electrical losses or the cost of a
good (read NOT modified sine wave) inverter big enough to run our day to
day electrical loads.

2. Heat can be an issue with or without conduit. Folks often like to bundle
wires up nice and neat with lots of ties. The wires inside the bundle can
be subjected to greater heat load from adjacent conductors than those in a
loosely filled conduit. I seem to remember ancor having a de-rating factor
for bundled wires...

3. Conduit limits the number of wires. Well, sure, but so does the size of
the whole you punched in the bulkheads to run them. If you didn't size that
hole big enough for the circuit you decide to add a year or two later you
have the same problem.

4. My recommendation to measure runs from the battery, out to the load, and
back to the battery is based on the expectation that most people will find
that logic easier to follow. It is a conservative approach that adds a bit
more safety margin.

At one point I pulled wire for a living so it's no surprise that I like
conduit. The ease of adding a circuit, the extra mechanical protection, and
the separation of AC and DC circuits are worth the downsides in my opinion.

The fact is that there are many ways to skin this cat. Figure out your
needs, given how you use your boat, and go from there.


Greg
S/V Ayla