light switch

[Scooter]

Any reason why a standard house light switch won't work with 12V inside my tear? They're cheap, reliable, and abundant.

[Woody]

I don't see why not. I used them in mine since I have 12 vdc and 120vac in my trailer. It was more of an cosmetic thing for me. Other than their size difference (Bigger) they work fine for the application.

[mexican tear]

Use the new rocker kind and you will not catch things on the switch. I use 120V switches for my 12VDC switches.

kai

[Scooter]

Use the new rocker kind and you will not catch things on the switch.

Good point. I'm thinking of mounting them so that when I'm sitting up they're shoulder level or higher. Hopefully there won't be much bumping into them. If it's a problem I've only got two bucks total in both switches and covers, so that's not much wasted money if I swap 'em later.

[angib]

The argument I have seen (in boatbuilding, not RV, environment) against mains voltage switches is that they can quickly get a high resistance because good conductivity is not their aim. The design priority of a mains voltage switch is to quickly create a big enough gap to avoid sparking - losing a volt across the switch is not important. In contrast, the design objective of a low voltage switch is to get good conductivity, as stopping a 12v potential is child's play.

What I don't know is whether, as the cynic in me suspects, this story was instigated by the makers or retailers of (more expensive) low voltage switches.....

Andrew

[Scooter]

Ya know, I stopped at some auto parts stores on the way back from Home Depot and those small lever type switches made for 12V are really discreet, and a big variety to choose from. House light switches are big and gawky in comparison.

[Woody]

Look at the ratings of the majority of low voltage switches ,toggle and otherwise, they are rated for 125-230 vac applications. There are some that are not. In marine enviroments there other variables that with time degrade contact surfaces causing a wide mutitude of problems. Which are not a problem to most RV's. The new rocker switches, like Kai mentions, that are available (120vac) look good. Besides there are so many different kinds of cover plates available, one could gear them to a particular theme you would like to have for teardrop or trailer. Just my thought

[Arne]

Problem I have with 115v light switches is they are deep. On a side wall, the box would have to stick out at least an inch. On an end wall, might not be too bad.

[Woody]

I hear you on the too deep part. It worked for me since I insulated my teardrop, I could easily accomodate the shallow box with no problem in the side walls due to they are insulated with 1.5 rigid foam. Since I have a 12 vdc and 120 vac side installed in my trailer it became a natural choice to tie both systems together with similiar hardware for appearance sake without spending an arm and leg on additional hardware. Even installed in the galley bulkhead wall, one could use them without insulated sidewalls. It is all a matter of personal preference in my book.

[Steve Frederick]

I used 12v switches, a couple of bucks each, from Radio Shack. Mounted them on blank plates. they work nice, and I'm not second guessing the manufacturer.

[Ken A Hood]

I got mine at DEL CITY. They have a wide variety;rocker, illuminated, black white....etc. #7500030 are the ones I got. They now have them in white, and they are AC rated( and low voltage DC) #7500050.

And they are under $1.00 each.......

https://www.delcity.net/tstore/servlet/ ... pageitem=1

[Ken A Hood]

I used 12v switches, a couple of bucks each, from Radio Shack. Mounted them on blank plates.

That's what I plan on doing as well. I have the switches, and blank stainless steel plates.
And I've just ordered a couple books on wiring.....RV electrical systems and Managing 12volts, both for under $25(CAD)

[Frank]

Going by experence, it is best to use a switch that is rated for the voltage, ampere rating. There is a difference in 12vdc and 120vac, why take a chance over a couple dollars, be safe, use the correct switch.

Just my 2 cents worth.

Frank

[wlooper89]

I found this type D/C switch at Radio Shack. The advantage for me was that they can mount in a small round hole and are not very deep. For the porch lights I used standard Decora type wall plates with a blank insert. A hole to mount the switch is drilled in the insert. The switch is labeled I-O. Sorry the photo is not a better close-up. The raceway behind the switch brings D/C power to the cabinet area.



Regards, Bill

[Larwyn]

My understanding is that a DC rated switch has a sear type mechanism which "snaps" open or closed regardless of how slowly the lever is actuated, while an AC switch lacking the sear mechanism opens and closes more slowly.

The only examples of misapplication I have seen were on emergency lighting in electrical substation control houses. They always put in a few lights that can be operated off of the 120 volt DC station battery. I have seen standard "house switches" work okay but the real problem comes in when somebody installed one of the "quiet" switches intended for 120 volts AC. That switch caught on fire at the first operation. I doubt there would be similar results at 12 volts but have never seen it tried.

Something else which was common in the 120 volt DC control circuits was series contacts. Seems redundant but doubles the open contact gap and the engineers consistently designed DC control switches with series contacts while AC circuits were switched with only one contact.

I usually try to use DC rated switches for DC, and if they seem not to "snap" when operated, I try to move the lever as quickly as practical. If the gap is opened slowly it will maintain an arc for a longer period of time, generating heat which is one of the required ingredients for fire.