Wire Gauge Question

Jonathan KC8RYW · Post by **Jonathan KC8RYW** » Fri Jun 21, 2002 8:56 am

Okay, we all know that a single [ 16 gauge ] wire can carry about [ 10 - 15 ] amps, more or less, depending on [ some ] factors.

Here's the [ question ] :

If you run power over [ two ] 16 gauge wires run in [ parallel ], how many [ amps ] can you carry?

20 amps?

I have a bad feeling [ Kirchoff's Law] comes into play here.

Monty · Post by **Monty** » Fri Jun 21, 2002 9:33 am

Hi:

If you note, most heavy gauge wire is [ Stranded Wire ] The
more strands of wire, the greater capicity of handling current
needs.

In short, having 2 [ 16 gauge ] wires side by side will have
twice the capicity of one.

Not really recommended, but can be done if you are in a pinch

The problem comes when you need to fuse [Each wire ] to a
power source

MS

Chris · Post by **Chris** » Fri Jun 21, 2002 10:17 am

Also keep in mind that if the wires are not of high quality and of the exact same length, one will have a higher resistance and therefore the loads will not be distributed equally across them.

ltec123 · Post by **ltec123** » Fri Jun 21, 2002 1:05 pm

I guess somtimes 1+1 does equel 2.

I can't say for sure how much but I think the capacity drops to 1.5 times the original gauge capacity only!

N4UMJ · Post by **N4UMJ** » Fri Jun 21, 2002 6:23 pm

Of course the factors to consider are: Wire Length, Amperage, and conductor size (circular mils come into play here)

Here is a useful chart for determining wire size and length for a known load at 12 volts dc.

http://groups.google.com/groups?q=wire+ ... com&rnum=4

I use stranded 4 Ga (copper) jumper cables (overkill --- Maybe??) in my car to deliver the power to my VHF/UHF/HF transceivers mounted in the trunk.

Also when your vehicle is running you have an additional 1.8 volts added in. (13.8 Volts) so this can compensate for voltage drops due to wiring etc. But when the ignition is turned off your back at 12V.

I saw a neat product that actually increases the voltage to 13.8 when your engine is not running. It was in one of the Ham magazines. Another way to squeeze some extra power out I guess!

Ed

jim · Post by **jim** » Fri Jun 21, 2002 7:48 pm

When in doubt, after the installation, perform a amp draw test with a clamp-on ammeter. At the same time, do a voltage drop test from B+ to load and ground to load. Do it UNDER LOAD! Max acceptable voltage drop over the distance of tha cable should be no more than approx 125-150 mV. Any higher than this indicates you need a larger feed.

Speaking of doubled up power feeds......
It peculiar that high powered Kenwoods use two hots and two grounds instead of single REAL sized cables.

N4UMJ · Post by **N4UMJ** » Sat Jun 22, 2002 8:07 pm

I just remembered another website that has some rather unique dc power products.

http://www.powerwerx.com/products.html

There have been many attempts to standardize the DC Power Connector in ham radio and it seems that now the Anderson PowerPole is the connector of choice.

I have never used one though.....

Ed
N4UMJ