Is there a “safety factor” built-in to the auxiliary switches?

MyDaughters20JL

Well-Known Member
First Name
Jeff
Joined
Jun 6, 2020
Messages
532
Reaction score
272
Location
WA
Vehicle(s)
20 JL Sport S
just wondering if there is any kind of a “safety factor“ with the auxiliary switches. I have a bunch of lights that I am planning on wiring in and one of the sets at 12 V, would be 14.2 A. Is that pushing the limits of the 15 amp circuit on either number three or number four switches?
 

DHW

Well-Known Member
First Name
David
Joined
May 30, 2019
Messages
373
Reaction score
451
Location
Atlanta
Vehicle(s)
2018 Rubicon
Occupation
Attorney
just wondering if there is any kind of a “safety factor“ with the auxiliary switches. I have a bunch of lights that I am planning on wiring in and one of the sets at 12 V, would be 14.2 A. Is that pushing the limits of the 15 amp circuit on either number three or number four switches?
They have fuses and relays. Personally I use wire that far exceeds the current draw of my accessory. And I'm no electrician but I'm pretty sure the 14.2 amps would be fine.
 

TheRaven

Well-Known Member
First Name
Kevin
Joined
Oct 22, 2020
Messages
293
Reaction score
392
Location
Reading, Pennsylvania
Vehicle(s)
2021 JLU 80th, 2020 Challenger Scat Pack, 2010 Tahoe Z71
just wondering if there is any kind of a “safety factor“ with the auxiliary switches. I have a bunch of lights that I am planning on wiring in and one of the sets at 12 V, would be 14.2 A. Is that pushing the limits of the 15 amp circuit on either number three or number four switches?
You'll be fine. A 15A fuse won't necessarily blow at 15.1A. It could, but fuses and breakers aren't designed to primarily limit continuous current, they are designed to limit current RAMP. I've personally witnessed fuses and breakers support 2x the current they were rated for simply because the ramp up to that level wasn't too fast and that level was not maintained for long. Also, wire and contacts are rated for current AT temperature. The vast majority of wire is rated at 80 or 90C. Current capacity diminishes with temp increase, so you need to consider the max temps your wire will be exposed to in order to determine how much "cushion" you have. If a wire is rated for 15A at 90c, and it's only going to see 60c, it'll easily handle 20A. But also keep in mind that engine bays can approach 200F (93C).

The moral of the story is that if you use quality components, you will have lots of breathing room. So a 14.2A load will be perfectly fine on a properly constructed 15A circuit using quality stuff.
 

Advertisement




Done Right LED
 



Advertisement
Top