TheAMCForum.com Homepage
Forum Home Forum Home > The Garage > Electrical - non engine
  New Posts New Posts RSS Feed - Gauge of Wires in Harness
  FAQ FAQ  Forum Search   Events   Register Register  Login Login

Click for TheAMCForum Rules / Click for PDF version of Forum Rules
Your donations help keep this valuable resource free and growing. Thank you.

Gauge of Wires in Harness
 Post Reply Post Reply
Author
Message
  Topic Search Topic Search  Topic Options Topic Options
davec1957 View Drop Down
AMC Nut
AMC Nut
Avatar

Joined: Jul/09/2010
Location: Massachusetts
Status: Offline
Points: 385 		Post Options Post Options   Thanks (0) Thanks(0)   Quote davec1957 Quote  Post ReplyReply Direct Link To This Post Topic: Gauge of Wires in Harness
    Posted: Oct/07/2021 at 7:18am
Can someone tell me the gauge of the wires in the 1970 AMX wiring harness? 
1970 AMX Bayshore Blue 390 4-spd GoPac
1970 AMX Commodore Blue 390 4-spd GoPac
Back to Top
tomj View Drop Down
AMC Addicted
AMC Addicted
Avatar

Joined: Jan/27/2010
Location: earth
Status: Offline
Points: 7544 		Post Options Post Options   Thanks (0) Thanks(0)   Quote tomj Quote  Post ReplyReply Direct Link To This Post Posted: Oct/07/2021 at 10:56pm
"as little copper as possible". 

A joke, but not really. Copper is expensive, factories have scale on their side, so the smallest guage that works and has minimal fleet-scale service problems.

Wire guage will vary with the particular load, there will not be one size. Instrument panel lighting is an amp or two, but the alternator/generator to battery wire is relatively fat.

Which wire?
1960 Rambler Super two-door wagon, OHV auto
1961 Roadster American, 195.6 OHV, T5
http://www.ramblerLore.com
Back to Top
davec1957 View Drop Down
AMC Nut
AMC Nut
Avatar

Joined: Jul/09/2010
Location: Massachusetts
Status: Offline
Points: 385 		Post Options Post Options   Thanks (0) Thanks(0)   Quote davec1957 Quote  Post ReplyReply Direct Link To This Post Posted: Oct/08/2021 at 6:32am
Thanks, Tom. It's the orange wire from alternator to regulator.
1970 AMX Bayshore Blue 390 4-spd GoPac
1970 AMX Commodore Blue 390 4-spd GoPac
Back to Top
Trader View Drop Down
AMC Addicted
AMC Addicted


Joined: May/15/2018
Location: Ontario
Status: Offline
Points: 6881 		Post Options Post Options   Thanks (0) Thanks(0)   Quote Trader Quote  Post ReplyReply Direct Link To This Post Posted: Oct/08/2021 at 2:58pm
Thought it possible to measure by the outside insulation. The wire on my 69 is 0.093" OD.
But I have several 16 gauge and 18 gauge wire coils that are anywhere between 0.090" and 0.110".
16 gauge would therefore be best recommendation without cutting the wire and actually measuring the stranded copper.
Back to Top
tomj View Drop Down
AMC Addicted
AMC Addicted
Avatar

Joined: Jan/27/2010
Location: earth
Status: Offline
Points: 7544 		Post Options Post Options   Thanks (0) Thanks(0)   Quote tomj Quote  Post ReplyReply Direct Link To This Post Posted: Oct/09/2021 at 1:07am
I don't know wire function by color, you'd have to look it up and post it.

If it's the main current-carrying wire from alternator to battery (or to solenoid to battery, etc) then it's large, 10 gauge, or something. Larger is better within reason.

If it's for the idiot light, or the sense wire, then "almost any" gauge would work, as it's carrying a fraction of an ampere. Even #30 might work -- but no car maker would put delicate #30 wire in a harness, it wouldn't last. So often wire size is actually larger than it needs to be (eg. #18 for battery-sense) simply because they can use easy crimp lugs. FOr a sense wire, you could use the same skinny wire for a 35 amp alternator or a 140 amp, since it's not carrying that large current.

Each wire has a function and a reasonable minimum gauge.

Trader, there's no standard of wire insulation size. For a given batch and brand, they're probably consistent, but unpredictable otherwise.
1960 Rambler Super two-door wagon, OHV auto
1961 Roadster American, 195.6 OHV, T5
http://www.ramblerLore.com
Back to Top
bigbad69 View Drop Down
Supporter of TheAMCForum
Supporter of TheAMCForum
Avatar

Joined: Jul/02/2007
Location: Ottawa, Ont.
Status: Offline
Points: 6668 		Post Options Post Options   Thanks (0) Thanks(0)   Quote bigbad69 Quote  Post ReplyReply Direct Link To This Post Posted: Oct/09/2021 at 9:42am
Originally posted by Trader Trader wrote:

Thought it possible to measure by the outside insulation.
The wall thickness of the jacket varies by the material used and the rated standoff voltage. While it is often possible to guess the approximate wire gauge by the overall diameter, it is not an infallible method. If you're going to the trouble of measuring the jacket diameter, then why not just measure the wire diameter? Much more accurate.

The orange wire is the voltage sense and power source for the regulator. It feeds all of the field current to the alternator, so there will be several Amp's running through it at max charge rate. I'll throw out a WAG that it's AWG 20 or 18.

Not knowing the reason for OP's question, I'd say use the thickest wire (lower gauge #) that is practical. Thicker is better for current capability, but it becomes increasingly difficult to work with. If trophies are part of the plan, then you'll need to carefully match what the factory did. You'll have to measure the wire diameter to determine exactly what was used.
69 Javelin SST BBO 390 T10
Back to Top
mstrcrftr View Drop Down
Supporter of TheAMCForum
Supporter of TheAMCForum
Avatar

Joined: Jul/12/2010
Location: houston
Status: Offline
Points: 2066 		Post Options Post Options   Thanks (0) Thanks(0)   Quote mstrcrftr Quote  Post ReplyReply Direct Link To This Post Posted: Oct/09/2021 at 9:44am
Originally posted by davec1957 davec1957 wrote:

Thanks, Tom. It's the orange wire from alternator to regulator.


That wire is an 18 ga.  all it does is send a signal.  so you could use either 18 or 16 ga.
Back to Top
 Post Reply Post Reply
  Share Topic   

Forum Jump Forum Permissions View Drop Down

Forum Software by Web Wiz Forums® version 12.03
Copyright ©2001-2019 Web Wiz Ltd.

This page was generated in 1.672 seconds.
All content of this site Copyright © 2018 TheAMCForum unless otherwise noted, all rights reserved.
PROBLEMS LOGGING IN or REGISTERING:
If you have problems logging in or registering, then please contact a Moderator or