12V DC Question

Executive wrote:
I'm assuming you're using this "hot" as your feed for the slide relay.

Huh? The OP never mentions anything about feeding a slide circuit?

RV @ 12V, house @ 110V, whatever. On any light switch, ALWAYS assume that both sides are HOT! That is why most light switches have any white wires painted or marked black. If the switch is on, all wiring between switch and fixture is HOT!

I'm assuming you're using this "hot" as your feed for the slide relay..:h. Put in simple terms, a switch simply breaks a hot lead into two parts. One side will always be hot, the other side "cold" until the switch is thrown, at which point the wires will be connected and therefore both hot. On a two prong switch there is no ground.....Dennis

You should pull the fuse for that circuit as arcing when working on the switch can blow a fuse. Also you should due to safety reasons, it is a good habit to always de-energize the circuit. You don't say what you are putting into the circuit, but you need to ensure that the circuit is large enough to handle it.

To avoid the possibility of blowing a fuse should you accidentally touch the hot lead to ground somewhere, personally, I would shut off the power source to the lead you're working with.

Good luck

Found it! Do I need to shut off all power from the batteries to tap into the Hot side (bottom prong, by the way) or do I have to worry about it, since its only 12V? Many thanks, again!

Here is a simple diagram where 12V runs to the switch and ground to the bulb, like pretty much every simple 12V circuit out there:

The wire is probably the hot side and the switch only breaks the electrical path when open. The light is most likely grounded at the fixture. All 12VDC ground lines on my coach are white and run in a daisy chain to common ground points. To check which side is live, use a volt meter or 12volt test light from ground to each side. The one that reads 12 volts will be the battery voltage side.

use a volt/ohm meter (VOM). one wire will always be hot while the other will be hot only when the switch is closed (light on).