[Amps] AC wiring

[Bill Coleman]

On Oct 13, 2005, at 7:23 PM, Lon W. Cottingham wrote:

> The one that got me was the
> statement that 220 AC wiring should be larger than 110 AC wiring.

Certainly not true. If anything, the 220 wiring can be smaller.

Although, these days, I doubt anyone is seeing 220, more like 240.

>         An SB-220 draws basically the same power from the AC mains  
> when
> powered by either 110 AC or 220 AC.

However, with 110, the I^2R losses in the wiring are quadrupled.

> The only real consideration is whether
> your Ham Shack's (household wiring) 110 AC wiring can pass the  
> required
> current to the amp with an acceptable voltage drop.

220 volt wiring will have half the drop with the same wiring, and  
result in one quarter of the power lost.

> My Ham Shack wiring is all done with #10 wire.
...
> While I am not suggesting that you do it, small amps like
> the SB-220 simply do not present a problem when operated from an  
> adequately
> designed 110 AC system.

Most residential wiring is done with either #14 or #12 wiring. (you  
can tell by looking at the breakers) Your #10 wiring is unusual and  
allows nearly 30 amps to be drawn through the circuit.

> However, a 220 AC circuit wired with #14  wire should be more than  
> adequate
> to power an SB-220 (again, I am not suggesting that you do this).

Why not? #14 circuit is capable of 15 amps. At 220v, this is more  
than 3300 watts. The fuses on the primaries in the SB-220 are, what?  
10 amps each?

Bill Coleman, AA4LR, PP-ASEL        Mail: aa4lr at arrl.net
Quote: "Not within a thousand years will man ever fly!"
             -- Wilbur Wright, 1901