Minimum AWG for wiring a pair of 100W lights

[Turbogus]

Hi gang,
I pulled from the bottom of my roll away a pair of nos but non descript fog lights. They are 100w H2 units that pull about 8.5 amps and pre wired with 16 gauge wire pigtails. My question; Wiring this pair of light to one switch. Is 14 gauge wire satisfactory? I've got a load of 14 gauge but minimal everthing else and I think it'll be fine for up to a 14 foot run, unless the data so far is inaccurate. So far research on the web yields tmi about non related elcetrical.

Thanks and a lift of the lynch lid for any responses.

 

[JPNinPA]

18 gauge

Wire Capacity Chart

 

[bobcat481]

What is #12 Awg for $800? Alex
8.5 Amps x 2 = 17 Amps. #14 awg. = 15 amps. >> Not Enough

#12 awg. = 20 amps. >>Much better
#18 awg. is SMALLER than the #16 awg. comming out of the pigtails.

Question:

Hi gang,
I pulled from the bottom of my roll away a pair of nos but non descript fog lights. They are 100w H2 units that pull about 8.5 amps and pre wired with 16 gauge wire pigtails. My question; Wiring this pair of light to one switch. Is 14 gauge wire satisfactory? I've got a load of 14 gauge but minimal everthing else and I think it'll be fine for up to a 14 foot run, unless the data so far is inaccurate. So far research on the web yields tmi about non related elcetrical.

Thanks and a lift of the lynch lid for any responses.

The chart referenced above IS is fact true, but I wouldn't call it "right". It doesn't take into consideration heat loss (more amperage) and wire length. Wire is cheap to buy, but if you have the #14, use it. Just make sure youe fuse it at 15 Amps.

 

[JPNinPA]

The chart referenced above IS is fact true, but I wouldn't call it "right". It doesn't take into consideration heat loss (more amperage) and wire length. Wire is cheap to buy, but if you have the #14, use it. Just make sure youe fuse it at 15 Amps.

Do you mean 20A fuse? Your calculation of current draw is 17 A. Thicker is better and will be stronger especially the connectors you use. Not arguing here but my 130W KC's came with 16 AWG. Just saying.

I agree with the fusing and would also suggest a relay if you were not considering that already.

 

[bobcat481]

Yes, its gonna pull 17 amps. but, if he's gonna use the #14 that he has on hand, it can only handle 15 amps. Granted the 15 amps. is figured for in a conduit (reducing its capacity to 80%), but being that it is in "open or ambient air" than it can be pushed harder. I was suggesting trying the 15 amp fuse, and seeing if it holds. The 130W KC's have #16's on the pigtails only, each single light's gonna draw 9 amps or so, so the 16 is fine for a single light. When 2 lights are used, then you gotta go X2. Hence around 18 amps. The wire coming from the switch or relay is feeding BOTH lights, not just one, and needs to be sized accordingly. The pigtails kinda play off the "tap rule". It's a shorter wire, and the only load on that wire is going to be from 1 light.

 

[JPNinPA]

This just pointed out I should have thought how the info would be interpreted. For the OP I would take it you are wiring a new circuit for the lights. I would run a short 20A fused wire from the battery to a 40A relay and an individual power wire to each light. Ground each light nearby to the frame. An additional 5A fused wire from power (either the battery or ignition power) thru a switch to the relay. This gives you the control of the lights without running up to 20a thru the switch and the losses of long power lines.

You could wire it as suggested one power wire thru a fuse and switch and splice off each light. This will require a heavier gauge wire and a switch capable of handling 20A.

PS The 16 gauge on the KC’s is from the relay all the way to the light. Not just the pigtails.

 

[bobcat481]

This just pointed out I should have thought how the info would be interpreted. For the OP I would take it you are wiring a new circuit for the lights. I would run a short 20A fused wire from the battery to a 40A relay and an individual power wire to each light. Ground each light nearby to the frame. An additional 5A fused wire from power (either the battery or ignition power) thru a switch to the relay. This gives you the control of the lights without running up to 20a thru the switch and the losses of long power lines.

I do concur. Make it so.

 

[Turbogus]

........ and...............drum roll...................done