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Current capacity of 1/4" & ring contacts


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A simple question that I'm sure will be quickly answered by someone who understands electrickery: what continuous current can these connectors carry, assuming they are well crimped, clean and weatherproofed/shrink wrapped and have appropriately sized conductors?  Many thanks for all responses.

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Mike

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That's brilliant, thank you, western.  Exactly the info I was looking for.  It seems that I can safely run a negative busbar with all four headlamp filaments connected to red ring connections with a yellow ring terminal lead back to the battery, all with appropriate sized wiring. And thanks for the link.

Mike

 

 

 

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2 hours ago, FridgeFreezer said:

If they're good quality (AMP/TE/Tyco) I'd believe the specs, if they're randoms from the internet I'd... well actually I'd throw them in the bin and buy decent ones :lol:

I agree with this. You will find a lot of them are made of thinner material and some ring types have less OD for any given interior.

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13 hours ago, Troll Hunter said:

That's brilliant, thank you, western.  Exactly the info I was looking for.  It seems that I can safely run a negative busbar with all four headlamp filaments connected to red ring connections with a yellow ring terminal lead back to the battery, all with appropriate sized wiring. And thanks for the link.

Mike

 

 

 

Bear in mind that halogen lights in particular are very sensitive to supply voltage, meaning a small drop in supply voltage at the terminals has a big effect on the light output. Consequently, it's really the resistance in the circuit supplying the bulbs which is the important factor, not just its ultimate current carrying capability. Big fat wires and larger terminals have a higher current capacity and also have a lower resistance, which is good, but every connector or joint you put in the wiring between the alternator and the headlamps adds a resistance which is probably equivalent to several metres of cable. Using well over-spec'd connectors and cable, and minimising the number of joints is important if you want to get the maximum amount of usable light out of your headlamps.

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Good points, nickwilliams, thank you.  I'm running 10AWG (5.26mm2) wiring through four relays, one for each headlight filament, and have dedicated earths from each headlight back to an earth busbar with 4AWG (21.14mm2) cable from there back to the battery negative post.  I hope this will minimise voltage drop to my headlights.

Mike

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3 hours ago, Troll Hunter said:

Good points, nickwilliams, thank you.  I'm running 10AWG (5.26mm2) wiring through four relays, one for each headlight filament, and have dedicated earths from each headlight back to an earth busbar with 4AWG (21.14mm2) cable from there back to the battery negative post.  I hope this will minimise voltage drop to my headlights.

Mike

That's massive overkill, 2mmsq is already more than enough.

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I can't remember where I copied the below table from, but it's what I'm using as a guide for selecting cable sizes.

As for the massive earth cable there will be additional loads earthed through that busbar and cable, so it may well be carrying ~50 amps when headlamps, driving/off-road lights and wipers are all in commission, and, of course, I want something in reserve, perhaps in case I decide to charge my iphone at the same time!

Mike

Amps 
@ 13.8 Volts

LENGTH OF WIRE
American Wire Gauge (AWG)
             
0-4 ft. 4-7 ft. 7-10 ft. 10-13 ft. 13-16 ft. 16-19 ft. 19-22 ft.
0 – 10 16-ga. 16-ga. 14-ga. 14-ga. 12-ga. 10-ga. 10-ga.
10–15 14-ga. 14-ga. 14-ga. 12-ga. 10-ga. 8-ga. 8-ga.
15-20 12-ga. 12-ga. 12-ga. 12-ga. 10-ga. 8-ga. 8-ga.
20-35 12-ga. 10-ga. 10-ga. 10-ga. 10-ga. 8-ga. 8-ga.
35-50 10-ga. 10-ga. 10-ga. 8-ga. 8-ga. 8-ga. 6 or 4-ga.
50-65 10-ga. 10-ga. 8-ga. 8-ga. 6 or 4-ga. 6 or 4-ga. 4-ga.
65-85 10-ga. 8-ga. 8-ga. 6 or 4-ga. 6 or 4-ga. 4-ga. 4-ga.
85-105 8-ga. 8-ga. 6 or 4-ga. 4-ga. 4-ga. 4-ga. 4-ga.
105-125 8-ga. 8-ga. 6 or 4-ga. 4-ga. 4-ga. 4-ga. 2-ga.
125-150 8-ga. 6 or 4-ga. 4-ga. 4-ga. 2-ga. 2-ga. 2-ga.
150-200 6 or 4-ga. 4-ga. 4-ga. 2-ga. 2-ga. 1/0-ga. 1/0-ga.
200-250 4-ga. 4-ga. 2-ga. 2-ga. 1/0-ga. 1/0-ga. 1/0-ga.
250-300 4-ga. 2-ga. 2-ga. 1/0-ga. 1/0-ga. 1/0-ga. 2/0-ga.
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