Switching a Ground instead of the Hot Leg

So I've found some anecdotal evidence that using a switch on the ground leg of a device isn't the ideal choice, but it's feasible. I wanted to throw out to the greater group what they think of this.


Here's the scenario. I'm adding more lights behind the grill and I'm out of Uplifter switches. If I run these new lights off of a set of new switches, to do it right, I'd need to add in some fuses and relays and lots of wiring.

One option that I can think of is this. If I accept the fact that the amber lights I'm installing behind the grill will NEVER be on without also having my Rigid Amber Fogs on, I can wire the hot lead for the behind the grill lights to the Rigids and run the ground into the truck cab, into a switch, and then to ground. When I interrupt the ground on the grill lights, the Rigids will remain on, but I'll be able to control the grill independently in a way. This also reduces the number of wires I run into the cab. I don't run a load through the switch if I ran straight from a hot source and I don't go through the effort of installing and wiring a series of relays.

I know it's not the "right" way, but I'm okay with that!!! Any reason I can't leave a load on a device (light) and just interrupt it's ground for on/off?



Thanks in advance.


Todd

a proper ground is just as important as a power. so if you are going to run a ground wire, you should treat it (guage wise) as the same as a power wire.

Thanks Noah. So if I do 12 or 14 gauge power, I should match it on the ground side.

Current = load and current is the same in all locations of a series circuit, so even though you are interrupting the ground side of the circuit, you are still switching the load and should use a relay if there's any amount of current involved. What light are you considering doing this with and what's its current draw?

What you have described will work, but sounds pretty ghetto in my opinion.

correct. you will also need to check the wiring to the other lights. tapping into them will increase the load so that fuse and wire will need to be upgraded as well

Ghetto, you bet.

Whelen Micro Pioneer draws 4 amps at 12 volts.

... and you're adding one or two of them to existing Duallies... how many Duallies?

Sounds like even AUX 4 should handle this depending on the exacty Dually model and quantity.

So for what I'm thinking, I'll have two Dually's at 1.1 amps each. Then add 4 amps each for the Whelen, I'll have 10.2 amps total draw. I have them on Up Lifter #4 which is rated at 10 amps, so I'll have to move them, which is fine.

What is the amp rating on each of the 4 switches?

1 and 2 are 30 amp, 3 is 15 and 4 is 10.

---------- Post added at 02:38 PM ---------- Previous post was at 02:38 PM ----------

I referenced this when I was searching.


Instructions for Ford Raptor Upfitter Switches