Wiring sizes

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Rod Johnson

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Oct 6, 2022, 2:26:38 PM10/6/22
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Per the discussion last night about wiring....This is related to automotive applications, and keep in mind it is for 'reasonable' lengths.

Use the right size wire for you project & don't overload you stock wiring system.
Here are some wire sizes & the loads they can handle:
AWG = American Wire Gauge
Up to   5 amps: 18 AWG ( any HT should be fine here)
Up to 10 amps: 16 AWG ( any mobile VHF radios should be happy here)
Up to 15 amps: 14 AWG  (the higher powered VHF radios should land here)
Up to 20 amps: 12 AWG (minimum size for HF radios)
Up to 30 amps: 10 AWG (better for 100 watt HF radios)
Up to 50 amps:   8 AWG ( a bit over-kill for most things)
Up to 65 amps:   6 AWG ( Cables to an auxiliary battery for charging)
Up to 85 amps:   4 AWG  (Barry's Rover 6M Amp!??  -may be marginal)

Remember, the connectors are also very important.  Trusting anything much larger than the power draw of an HT or low power mobile rig, to a lighter socket ( Auxiliary power socket ) is problematic and subject to scrutiny, if any unusual operational characteristics are noted.
The bigger the number, the smaller the wire. 
  Using smaller wires than the above ratings may stand the heat; and very long lengths ( not common with most of our radio installations) will also have voltage drop problems.

 Rod J

Gerard Hickey

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Oct 6, 2022, 5:19:16 PM10/6/22
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Another thing to be aware of is that there are instances where some Chinese manufacturers have been producing a rated wire of say 10 AWG. In reality what they are producing is something close to a 12 AGW wire that has a thicker insulation on it to give it the appearance of a 10 AWG wire. The jacket on the wire will usually be marked with the more favorable size. 

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ba...@k7bwh.com

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Oct 6, 2022, 6:28:01 PM10/6/22
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I’m wiring my Land Yacht, so I figure it’s good to follow boat-builders recommendations. You should take into account the wire length and allowable %voltage drop to pick your wire sizes. Also take into account temperature ratings which’ll depend on if the wire is bundled with other wires and if it’s enclosed in conduit.

One such good chart is from Blue Sea Systems: http://assets.bluesea.com/files/resources/newsletter/images/DC_wire_selection_chartlg.jpg

This is based on the ABYC (American boat and yacht council) which has been studying this for a long time.

For me, I need 50-amp capability, less than 3% voltage drop, and it’s a compact 48-volt system where all my runs are less than 10 feet total. So, 6 AWG has plenty of safety margin, not to mention it’s more economical and easier to bend than other guys running 12v systems and double-aught welding wire.

There’s a lot of good techniques to be learned those who build marine electrical systems. For one example, tinned copper wire and tinned connectors will last longer than bare copper. As Rod mentioned, connectors are important, and round screw-on connectors are more secure than spade or push-on connectors. There is tons of great basic information from Jeff Cote on YouTube at Pacific Yacht Systems, https://www.youtube.com/c/PacificYachtSystems/videos

73 Barry K7BWH

Rod Johnson

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Oct 6, 2022, 6:53:20 PM10/6/22
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Gerard,
  Good point!

  Also, there is now a lot of the the red/black wire on E-bay, that is labelled 'CCW'.   It is often being labeled as audio/speaker wire.
  That 'CCW' stands for "Copper Clad Wire".  It is aluminum wire that has a copper cladding.
   It is relatively inexpensive, does not carry the same current rating, and but relatively stiff. Because it is relatively stiff, is prone to mechanical failure at flex points.
 It is OK if mounting stereo gear in a car ( assuming you upsize it for current capability), but for applications like portable radios and non-fixed power wiring I would recommend you stay away from it.
  Here is a good e-bay example, below.
.  The title says 50 feet of 10 ga.; but if you look down to the specs below, it mentions 'coppper coated wire' or 'CCW'.  It is about 1/2 to 2/3 the cost of good  quality stranded 100% copper wire.   I notice several listings for 'CCW' in the neighborhood of $30,  The cure copper (sometimes labeled 'OFC') is generally in the $50-$60 range for similar  50 feet of 10ga wire.

  A look at the strand count ( number or actual strands and the size of the individual strands) you will see one reason it is stiff, besides the fact that is it aluminum.)   The 'good stuff' will have many more individual strands of smaller wire.


Rod Johnson
-----Original Message-----
From: Gerard Hickey <unixg...@gmail.com>
To: issaqu...@googlegroups.com
Sent: Thu, Oct 6, 2022 2:19 pm
Subject: Re: [IARC] Wiring sizes
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