Wiring Amperage Capacity?

Submitted: Friday, May 18, 2007 at 09:34
ThreadID: 45604 Views:2582 Replies:7 FollowUps:2
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I'm looking to install a UHF into my roof console. At present it's only wired up with the factory 12V wire used to power the interior light, will this gauge of wiring be able to handle powering the UHF and the interior light or will I need to run separate power/earth up there? I would estimate the wire to be 0.75 - 1.0mm2, and it has a 10A fuse.
UHF will most likely be a GME3220, and the specs I've found look as if it has very little amperage draw, but I'm no sparky so would like to hear others opinions.

Thanks

Gav
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Reply By: Wayne (NSW) - Friday, May 18, 2007 at 09:42

Friday, May 18, 2007 at 09:42
Gav,

The wire should be OK,but the UHF should be hooked up to the second battery.

Running a separate cable from the second battery or to the main battery if a second battery is not installed, to the radio would be the way to go.

Wayne
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Reply By: Robin Miller - Friday, May 18, 2007 at 09:45

Friday, May 18, 2007 at 09:45
That should be enough Gav (0.75-1mm)= approx 6 amps capacity.

However I don't like any volts drop , and would check by measuring volts with no
interior lights on and then switch ALL interior lights on and measure again.

Any more than about 1/4 volt (0.25) and I would add a new wire.

Following from Waynes comment, I prefer to use a wire that is switched by acessories so that radio is on when key in ignition, so that you don't have to remember to turn it on.

Always seem to find someone in any group that forgets this !


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Reply By: Stu050 - Friday, May 18, 2007 at 09:57

Friday, May 18, 2007 at 09:57
I would run separate power/earth up to the UHF, otherwise the UHF won't get power unless the interior light is on.
AnswerID: 240710

Follow Up By: Gerhardp1 - Friday, May 18, 2007 at 10:55

Friday, May 18, 2007 at 10:55
That's true, but only if the wiring to the globe is cold. If it's hot, the radio will work.
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Follow Up By: Robin Miller - Friday, May 18, 2007 at 11:04

Friday, May 18, 2007 at 11:04
As per Gerharp1, Stu

Globe is normally powered and requires earth contact via door opening etc to turn on , hence not normally required and the volts test.

You will have to earth radio though via its earth lead and not use case as earth.

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Reply By: Member - Bentaxle - Friday, May 18, 2007 at 12:48

Friday, May 18, 2007 at 12:48
Gav
Have just been down that track. You will need to run a separate power supply to the UHF, which is linked to a second battery, failing that wire it into your ignition switch
Mike
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Reply By: Mainey (WA) - Friday, May 18, 2007 at 13:04

Friday, May 18, 2007 at 13:04
Why not run an independent positive & negative cable from the Aux battery with a reasonable fuse. I use an independent on/off rocker switch that has a light built with-in the rocker switch that illuminates only when switched on, it’s mounted in the dash where it can readily be seen as the radio is mounted down low out of general view while driving.
AnswerID: 240747

Reply By: Sand Man (SA) - Friday, May 18, 2007 at 14:39

Friday, May 18, 2007 at 14:39
If the overhead console was "factory fitted" surely it would include its own 12 volt fused supply?
I assume this is what you may mean by the factory 12 volt wire used to power the (separate) interior light on the console, rather than the standard vehicle's roof light.
This circuit should easily accomodate the UHF's supply.

If not, run a separate twin cored supply cable direct from the battery and fused at the battery end. The cable is easily routed through the firewall, up the corner window column and underneath the headlining close to the windscreen.

Bill


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Reply By: gav99x - Friday, May 18, 2007 at 14:49

Friday, May 18, 2007 at 14:49
Thanks for all the reply's guy's, greatly appreciated. Looks like the safest way to go is to run another twin core direct from the battery (only have a single battery by the way). And yep, the interior light is switched to negative with constant power so feed should be ok independent of light (found this out the hard way by cutting both wires simultaneously and blowing the fuse LOL)

Sand Man - sorry bit of confusion there, console I have constructed and upholstered myself, I've re-used the original Jackaroo interior light and wiring, this was the 'factory' I was refering to - the OEM 12V feed to power it. As you say easy to run a new cable up the A Pillar under the trim, had this off last weekend for something else so should be straight forward.

Thanks again
AnswerID: 240775

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