This week in stupid questions : Any reason I can't use a 120v light switch with 12v?

[neoneddy]

That's it I guess, is there any good reason I could use a normal house switch for 12v lights? I was thinking just to keep it familiar.

Right now I have some 12v switches but considering a change as I'm approachig final fit and finish.


Sent from my iPhone using Tapatalk

[Slug]

Fine to use But they won't last as long as when used in a house ie 50 years you will get 30years
Just thet 12v has a higher arc in the switch contacts
Other than that as you say everyone is familiar with that style switch
Most RV manufactures use them and now useing wireless house switches in there place no wires in the wall

[buswarrior]

The first rating to consider is amperage.

Is the switch rated strong enough for the amperage you will send through it?

The switch does not care about voltage.

However, as noted in the last post, DC sparks the contacts, which eventually degrades the contact point, introducing resistance, which makes heat, and in the right conditions, a fire.

The higher the amps, the more you MUST think about DC rated switch gear.

For a few LED lights, there will be no need to worry for a long time. Be sure there is at least some sort of electrical authority type rating on the switch you choose. No junk parts in the conversion electrical!!!

Happy coaching!
Buswarrior

[chessie4905]

http://www.busconversions.com/bbs/index.php?topic=14180.15

[richard5933]

Here's a great explanation of the answer to this question from the Mouser website:

https://www.mouser.com/blog/which-switch-who-cares-if-its-ac-or-dc

Apparently there are differences in the make/break of the circuit, and since AC current flows through a zero point twice a cycle the arc extinguishes much quicker due to the differences there are factors to consider when using an AC switch on a DC circuit.

There are various 'rule of thumb' calculations for using an AC switch on a DC circuit, but ideally one would find a switch with a DC rating.

The good news is that there are many DC rated wall switches out there, mainly aimed at solar and off-grid installations. Leviton also has some new switches rated at 3 amps @ 24VDC intended for use in LED lighting systems. It's also possible to use a standard connection/switch box with a blank cover, and then mount a DC rocker switch in the blank panel.

[luvrbus]

The wall switches have been around for years with AC/DC rating  ,the click type AC switches last a long time on DC the silent type are a waste of time,I used the AC/DC paddle switches 25 years ago (not cheap) and they are still going you get those from a industrial electric supply you won't find those at H/D or Lowes.A tip for you if you find wall switches that do not say AC or DC but only have a "V" labeling those work on AC or DC   

[bigred]

Be careful of your amps .wattsxvolts = amps thus if you are using the switch on ten 10watt lamps you already have 12 amps .Of course switches are available in 15,20 and 30 amps .

[bevans6]

The DC arc is really only a big problem (if you can call it a big problem at all) with inductive loads being switched off by the wall switch.  You can damp the arc with a capacitor or a diode (diodes really common internally within relays, for example, and capacitors along side points in a points/coil ignition system).  If you use a switch within it's ratings, you'll be fine.  If you use a switch to control a relay that controls the load, you'll be fine.  If you use a switch to control LED lights, you'll be fine.  And so on.  If you use a switch to control a DC motor of a current draw up around 80% of the current rating of the switch, I probably would find another way to do that.

Brian

[dtcerrato]

We've used a common 110 vac house switch on the bus master bedroom wall @ the rear entry door to operate an exterior 12 vdc light for 38 years now without issue.

[azdieselman]

Volts X Amps is Watts

100 Watt load at 12.6V is 8A.