QUICK: Is it BAD to switch the ground on/off instead of the +ve?

**wardemon666** · 07-21-2005, 02:49 AM

I accidently soldered my power wire directly to my inverter, im now asking myself if I can use the ground to switch it on and off instead?

I know it will work, but is it dangerous?

Also, i forgot to fuse the +ve also, but I know that my inverter has 2 fuses @ 25 in it.. will that be good enough?

Thanks a lot!

**KyleYankan** · 07-21-2005, 03:37 AM

Question 1: It's fine to have the inverter ground be the swithc, but better practive to have the +ve switched. If it's already soldered, just desolder it. you can get a de-soldering pump for $2 at radioshack. Not a hard job to do.

Question 2: Nope. Abosultely not. You want a fuse as close to the abttery as possible. Supposed your +ve line breaks and shorts on the car's frame? Fire! Dead battery too. :-)

Anyways, good luck. Sorry to delived bad news :-/

**Tidder** · 07-21-2005, 03:54 AM

It's true.

**lexanite** · 07-21-2005, 05:03 AM

Originally Posted by wardemon666

I accidently soldered my power wire directly to my inverter, im now asking myself if I can use the ground to switch it on and off instead?

I know it will work, but is it dangerous?

Also, i forgot to fuse the +ve also, but I know that my inverter has 2 fuses @ 25 in it.. will that be good enough?

Thanks a lot!

2 fuses your inverter has are to protect the lines if happen short circuit inside the inverter. You need fuse at positive wire nearest to the battery for safety. If the positive wire jacket / insulation breaks due to friction with car body (because of vibration) and make a short circuit to negative wire or the car body, the fuse will blown. Safe your car from burning possibility. Short circuit at 3 meter distance, with AWG10 let say, will produce around 14 to 15 KW dissipation. It produce a very loud sound. Other possibility, the battery will damage or even blows. So better do it now.

Better switching at the positive line. It more safe. You won't be surprise if someday your inverter is on while the switch is off. Dangerous .... it will make a fireworks someday.

Usualy I disconnect the wire from negative battery (not the positive) when I intent to leave my car for more than 3 days. Hope this info is usable for you.

**CavityCr33p** · 07-21-2005, 07:03 AM

Chris who promotes the DSSC told me that I could switch on/off my Inverter with the ground connected a second 30 amp relay, he said just to leave the inverter on and let the ground turn it on and off through the DSSC. IS this ok? He said you could use either the 12v constant or the ground.

**DeltaFX** · 07-21-2005, 07:05 AM

Yep, if you look how things are wired in a recent car, most

**CavityCr33p** · 07-21-2005, 08:12 AM

So it is ok to switch on and off via ground?

**evandude** · 07-21-2005, 08:32 AM

it might depend on the inverter. if it's poorly designed, the inverter might still be able to (weakly) ground itself through the 3rd (ground) prong of the AC plug, through the PSU, to whatever other grounding points you have (which may include the audio grounds)... which would almost certainly kill some stuff... and even if you had good enough grounds past the inverter to handle it, it would just not turn off.

however, I don't imagine most inverters would be designed that way. but feel free to be the guinea pig and tell us if you can blow the **** out of your sound card and/or head unit or amp inputs

**Jahntassa** · 07-21-2005, 11:01 AM

If the inverter can find ground through the casing touching the car..then switching off the ground wire wouldn't do much.

I agree, it's safer to switch off the + voltage.

**Speedsterworld** · 07-21-2005, 11:22 AM

I agree as well, if any item touches it, including you when you've switched off ground, you may just join the circuit

, and it wont feel nice, that's one reason we disconnect the ground wire from the battery instead of the power side first.

There's just so many factors that can create a ground, but only one can be power, be safe :P