Re: scirocco-L-digest V1 #1897

[Brian Dettling <aa821@acorn.net>]

RE: Wire gauge redux

Dan is right.  Two g. is appropriate for rear batty mount (BTDT 2x using 
that size).  I was addressing the runs from front batty mount to starter 
and aux grounds.  And yes, it was sorta joshing to quote Kelvin's Law.  
NOt really pertinent today when codes have decided for us and other 
things beyond economics determine wire size.  But didn't know wire guages 
changed since the 30's when my sources (bought old house, got lotsa stuff 
included) were printed.
Sorry for waste of bandwith.



Date: Sun, 23 Sep 2001 15:23:06 EDT
From: BFDEIHL@aol.com
Subject: Re: Copper gauge/ OT

Sometimes it's hard to tell when somebody is kidding, over the net.  The
"economics" of running the smallest proper guage wire is a real world
consideration when you are planning a building install, but so is the Vdrop
calc.

The lower the applied voltage, and the higher the amp load- the more
significant the effect of voltage drop in a conductor.

The math:

for copper conductors- (rule of thumb equation)

25.8, times distance to load in feet, times amp load-divided by conductor
cross-section in cir. mil.= Vdrop

#2 ga wire- 66360 cir mil (ref. table 8 NEC)
#6 ga wire- 26240 cir mil

Considering a 90A load, and 15 feet from battery to load

-- Brian D./OH
How can you be in two places at once when you're not anywhere at all...
Firesign Theatre

q

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