[VAC] Re: Don't mount solar on roof.

["Dr. Gerald N. Johnson, electrical engineer" <geraldj@xxxxxxxx>]

> Just thought I'd throw my 2 cents worth into the discussion.  Thought it is
> important to tell you that stranded wire will carry many times more current
> than solid wire of the same gauge. 

That is NOT TRUE for DC or any audio frequency. It is true for
frequencies of 20 KHz and up, more so if the individual strands are
insulated and the wire is braided so that each strand occupies the
exterior at some point during the run. That is called Litzendrat wire.
The need for insulated strands comes from skin effect due to alternating
currents. Its not a problem at 60 Hz with wire sizes under an inch or
two in diameter. Litzendrat wire is little benefit above about 1 MHz. 

At DC, solid and stranded wire of the same cross section carry the same
exact current with the same exact voltage drop and heating. Often a
stranded wire has a slightly greater cross section than the
corresponding solid wire simply because the strands are standard wire
sizes instead of specials.

Vehicular wire is better off to be stranded because small strands flex
better than large wires and so break less often. Crimp connections to
stranded wire are easier to make and have them hold well.

  I opted to use 8 gauge "well
> wire" (red/green/black) for circuitry in my Safari.  I don't think you can
> plan too large a wire.
  
This is MOST CERTAINLY TRUE. The only troubles with using a very large
wire are getting good connections to small devices like switches and
receptacles, finding passageways for the wire, and handling the wire
itself. When you exceed 1/0, in my experience, it takes special tools to
bend the wire, you can't easily do it by hand. Overly large wire also
extracts a weight penalty which then is compounded as a towing vehicle
fuel penalty.

Amateur radio cable specialists such as Cable X-Perts, Inc
(http://www.cablexperts.com) carry two conductor stranded cable
(black/red) in 18 gauge through 8 gauge. In rolls of 50', 100', and 250.

Gerald J.