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WrkdbfGuy · 08-12-2018, 09:11 AM

I recall somewhere that said it was okay to add a switch to a 12 volt DC line without turning off the power because the voltage was so low you wouldn't even feel it. I did add the switch and all went well. (This was inside the coach BTW)

Now I need to replace a bad flush switch on my 12 v DC toilet, but the manual tells me to be sure to disconnect power before starting. Is this for safety purposes? I wouldn't want to get shocked or worse ... Or is it just to keep the toilet from flushing/filling while I'm working on it?

I apologize if this is a stupid question. I know just enough about electricity to be dangerous as the saying goes ...

Thanks, Bill

96Bounder1st · 08-12-2018, 09:15 AM

The best reason to disconnect the power is so, by accident, you will not blow a fuse that may be really hard to find.
If you do not want to disconnect power at least tape each end as you take it off the switch. Life will be better.

Terry

JJH3rd · 08-12-2018, 02:58 PM

With 12v battery powered systems, like the ones used for the coach's power, you are equally likley to melt the wires and could get a serious burn from molten metal if the positive and negative wires come into contact (like a small spot weld).

rgvtexan · 08-12-2018, 03:08 PM

You can always disconnect the battery, and wear eye protection.

lymanlouis · 08-12-2018, 03:17 PM

Best practice is to cut the power. But, with 12-volt it's common to just get on with it. Some of the concerns have already been laid out by others. I rarely disconnect the main but will occasionally pull a fuse, and I almost always use electrical tape if the leads will be exposed for more then a few seconds.

Good luck.

MSHappyCampers · 08-12-2018, 03:35 PM

You won't get shocked but you could blow a fuse!

**Spdracr39** · 08-13-2018, 05:29 AM

12 volts won't shock you but it will melt your wedding ring into your finger. Don't ask me how I know. Turn the power off.

Soppy · 08-13-2018, 06:01 AM

Adding a switch isn't to bad .You won't get a shock , but if you are working on something with a circuit board and the wire happens to touch the circuit board , you can do $$$ in damage. I learn from my mistakes. It's always best practice to disconnect the power first and double check the wiring before reconnecting the power.

baraff · 08-13-2018, 06:39 AM

It's only 12 volts, right? Well, look what can happen in the right circumstances with a 9 volts battery.
This is a lot of power in a 12 volt battery.
Turn off the power first.

https://www.youtube.com/watch?v=IoAO1S5w7KM

Old-Biscuit · 08-13-2018, 01:01 PM

You can work on 'electrical' wiring live/hot PROVIDED you do NOT touch ANY ground source

Course it only takes ONCE and you might not attempt it again

Turn the power off..........especially when ones electrical knowledge is just enough to be dangerous

Dropthejacks · 08-13-2018, 01:27 PM

Ain't the volts you have to worry about, its the amps that get you.

tcg · 08-13-2018, 02:21 PM

You've got some good answers. It won't kill you but you could blow a fuse or short out a piece of equipment on the same fuse but...

Now I'm curious, why not just kill the battery, by switch or disconnect?

ScoobyDoo · 08-14-2018, 09:39 AM

Quote:

Originally Posted by spdracr39

12 volts won't shock you but it will melt your wedding ring into your finger. Don't ask me how I know. Turn the power off.

Most things I'm likely to be working on, if wires I just try not to ground, (or sometimes short to ground to be sure I got the right fuse. But if I'm dealing with something hooked with cables the ground will be unhooked, and I have some short (1-3 inches) pieces of heater hose to slide on battery posts, to be sure the stiffness of cable does not spring back. And when working near batteries always unhook ground first, and replace last. All grounds! I have seen, for example, people told to remove one at a time to clean connections. Giving this advice to a stranger that might be clueless should be called assault. If you wrench hits ground post and grounded metal at same time, nothing happens. But if the ground is connected, post-wrench-ring-frame will burn. post-wrench-frame, you have lighting in hand, and can make explosion fire in your face plus acid all over the area.
Been there, done that, acid ate the tee shirt. That is why I have the hose pieces.

WrkdbfGuy · 08-14-2018, 10:13 AM

Quote:

Originally Posted by tcg

Now I'm curious, why not just kill the battery, by switch or disconnect?

It's hot out and dark in the bathroom, so I just figured if I don't have to kill the A/C's and lights it would be a more pleasant job. I looked through the fuse box - which is fairly well labelled by the way - and I didn't see an obvious fuse for the toilet.

But I have decided to kill the power. All in all this flush switch replacement *should* be an easy/quick task - two screws and three wires. The toilet to wall clearance may be an issue though. It's probably the "Bath GFI" fuse and I will check that one out before starting the work. If that fuse doesn't stop the flush mechanism, I'll just use the disconnect switch.

Thanks for all the good replies, all.

Bill