wire gauge

[mty pocketz]

I'm curious as to why many people think they have to have as large of a wire as possible for any install. Many years ago I was an electrician's apprentice and if Iremember correctly, a 12 gauge wire is good for about 20 amp. On a 120volt AC circuit, that would be good for 2400 watts, according to ohm's law. Many of the electrical panels we installed were fed by 3 gauge and up, which is good for 150-200+ amps.
Also, much of the electronic devices and systems I worked on in the Army used far more power than most CBs or amps and were fed by smaller wires than I see and hear people using for simple installs.

[ltdoc]

There's a difference between AC and DC, one of those differences is that an adequately sized conductor at AC may be too small for the same amount of current flow at DC. That deals primarily with the resistance of that conductor and the length of the run. The voltage drop because of that resistance at DC can be very large when compared with AC. I have no idea what the current rating is for particular gauges of wire at DC, just been too long since I had to know that. I do know that if you go by the AC current rating you can certainly be stuck with a too small conductor. Make sure you are looking at the table for the type of service, AC or DC.
- 'Doc

[p38]

I have always ran a 250watt noise filter with my radios I use 10 guage 25 amp capable I have put my magnum on it /the Stryker 955hp and recently an s9 all have turned out quite well!

[mty pocketz]

Thanks Doc. I do understand there is a difference between AC and DC, but I still don'tthink there is a need for the size of wire some people run or recommend to others. Like p38 said, he uses a 10 gauge and doesn't have any issue. However, there are some people that claim you need at least an 8 or 6 ga for a stock radio.
While in the Army, often I worked in a converted semi trailer or a smaller "shelter" that could be mounted on a truck. They ran off AC, but we had DC inside also. The feeder wires coming from our transformers we used were about the same size as what some people use on CB, amp, or car stereo system installs and we ran multiple pieces of test equipment and communication equipment on them, which I'm positive pulled more current than a CB and amp

[Deleted User 14541]

I haven't heard a lot of people recommend 6 or 8 awg wire for a radio unless it is a high power unit with a built in amplifier.

[MDYoungblood]

A lot of people use the stereo amplifier kits from stores like Walmart, K Mart , Best Buys, etc. and you really have to look at the wire. It will say 8 gauge (second pic is 4 gauge) on the box but most are smaller than that, here are a couple examples,



I have always recommended running one size larger then the equipments power leads and a size larger then that if the run is over 10ft.

3's

Greg

[silvereagle1]

I've always used 10 gauge wire. Never had issues before with 250 watts. I did change over to 8 gauge a few months ago. I can't tell any difference in performance. Doesn't seem to have made any difference.

[Deleted User 14541]

A lot of people use the stereo amplifier kits from stores like Walmart, K Mart , Best Buys, etc. and you really have to look at the wire. It will say 8 gauge (second pic is 4 gauge) on the box but most are smaller than that, here are a couple examples,



I have always recommended running one size larger then the equipments power leads and a size larger then that if the run is over 10ft.

3's

Greg

They will get you on the car audio crap. I've been happy with some brands but the last I bought was supposed to be 1 awg but was 4 awg with super thick insulation. Finally just laid down the cash for welding cable like I should have done years ago.

[MDYoungblood]

They will get you on the car audio crap. I've been happy with some brands but the last I bought was supposed to be 1 awg but was 4 awg with super thick insulation. Finally just laid down the cash for welding cable like I should have done years ago.

I guess I'm lucky to have a bunch of electrical supply houses in my area that I can get wire from but I did want to point it out to those that use the kits. I have used welding leads in the past but I like the color code ,red, black, and green and use power poles to match the wire.

3's

Greg

[Bluerunner]

It often doesn't take really big wire to "handle" high current. Kinda depends on what you mean by "handle".

Its gotta be big enough to deliver the needed current and not to heat up or melt and the insulation has to withstand the voltage.

For our CB & Amp purposes I thing the major concern is the voltage drop.

Put a volt meter at the battery / power supply output and get a reading when keyed up & modulated. Then put the meter at the amp input and take a reading. Its not uncommon to see a voltage drop at the amp input of .5 to 1.5 volts even with pretty big wire. Everything will still work fine but just not optimal. Bigger wire can sometimes prevent a voltage drop on maximum voice peaks and give a cleaner signal.

[Deleted User 14541]

Exactly right. Voltage drop is what we try to avoid with what some call overkill wiring. Yes the amplifiers will work on much smaller gauge but when the voltage falls off with modulation you lose headroom. Some people are ok with that and some aren't.

[rickk]

The problem isn't that it is DC instead of AC, but that it starts out at only around 14 volts, not 120 volts.

A couple volts of drop at 120 volts wont even be noticed.

A couple of volts of drop when you start off with only 13 or 14 is a much bigger deal.

Going from 14 to 12 volts (only a 2 volt drop) will cut the delivered power by around 27%, whereas going from 120 to 118 volts (still only a 2 volt drop) only drops the delivered power by bout 3%.

Rick