will a regular household 110v light switch work on 12v DC ?

[Suavek K]

Hi guys,
I have searched/ cross searched, youtubed, googled, everything i can think of....

I want to save on buying 20-30$ light switches in my boler, so i was hoping to use household switches, any idea how to wire those in a 12V DC setup?

when i plugged the wires in directly and then hooked up my LED's to the little tiny holes in the back the wires from the battery got REALLY HOT....

what am i doing wrong?

Please help!

thanks

[floyd]

Yes , a standard household light switch will work on 12V if wired correctly,but it sounds like you hooked both wires from the battery to the switch!!
That's a NO-NO!
You should break the Positive wire across the standard light switch to the load and return the Negative wire schematically directly back to the negative side of the 12V source. Also...most modern 110V dimmer switches will not work work on 12V.
Most 12V switches are about $3... What are you trying to do??
Contact me directly if you need further assistance.

[Byron Kinnaman]

You can go to any Radio Shack, Wal-Mart, hardware store and find lots of switches that are smaller than household light switches.

Think loop.... The wires from the battery will form a loop when connected to the switch and the light. The switch either completes the loop or opens the loop. (light is on when loop is completed, off when open).

Be careful when messing with 12volt systems and batteries. A battery can delivery a lot of current for a short period of time. Enough to burn up any trailer wiring.

It would be best if you found somebody close that could help you with your wiring. Trailer fires aren't much fun.

[Roy in TO]

Originally Posted by floyd

Most 12V switches are about $3...

To get an idea of what is available search ebay for "12V switch"

[Andrew Gibbens]

On a more general issue of using house voltage switches on 12v circuits, it isn't ideal if you are trying to conserve a battery. If you are hooked to the mains via a converter, then it doesn't matter much.

Household voltage switches are designed not to arc/spark (and so eventually burn out) when they are operated by opening the contacts wide enough - but the current is low enough that the resistance doesn't matter. 12v switches don't need much of a contact gap, but the current is big enough that a low resistance is required, to avoid a voltage drop at the switch that will, for example, reduce the output of a light connected to the circuit.

If you dismantle a household switch, you'll usually find contacts that work like a pair of hands clapping - quick to make or break, but not very good contact. In contrast most 12v switches use 'wiping' contacts (just like the exposed switches in Dr Frankenstein's lab!) where the wiping action keeps the contacts clean and so lowers resistance.

Now this is the situation here in Yurp where we use that scary 240volt electricity - maybe an American expert will tell me that 110volt switches don't work that way, though I bet they do.

[Byron Kinnaman]

Originally Posted by Andrew Gibbens

On a more general issue of using house voltage switches on 12v circuits, it isn't ideal if you are trying to conserve a battery. If you are hooked to the mains via a converter, then it doesn't matter much.

Household voltage switches are designed not to arc/spark (and so eventually burn out) when they are operated by opening the contacts wide enough - but the current is low enough that the resistance doesn't matter. 12v switches don't need much of a contact gap, but the current is big enough that a low resistance is required, to avoid a voltage drop at the switch that will, for example, reduce the output of a light connected to the circuit.

If you dismantle a household switch, you'll usually find contacts that work like a pair of hands clapping - quick to make or break, but not very good contact. In contrast most 12v switches use 'wiping' contacts (just like the exposed switches in Dr Frankenstein's lab!) where the wiping action keeps the contacts clean and so lowers resistance.

Now this is the situation here in Yurp where we use that scary 240volt electricity - maybe an American expert will tell me that 110volt switches don't work that way, though I bet they do.

Wiping action is needed for low current circuits. 12 Volt, 120 Volt, or 240 Volt circuits can be low current or high current, they can be high inductance or simply resistive. The difference in switches is the spacing of the contacts. 12 Volt contacts can be much closer together than 120 Volt and 120 volt contacts can be closer than 240 volt and so on and so on.

When I said low current that would be current in less than 100 mA. Most trailer lights are in 1 to 2 Amp area.

A smaller switch might be a good idea only because of how it would look in a small trailer.

[steve dunham]

Originally Posted by Andrew Gibbens

On a more general issue of using house voltage switches on 12v circuits, it isn't ideal if you are trying to conserve a battery. If you are hooked to the mains via a converter, then it doesn't matter much.

Household voltage switches are designed not to arc/spark (and so eventually burn out) when they are operated by opening the contacts wide enough - but the current is low enough that the resistance doesn't matter. 12v switches don't need much of a contact gap, but the current is big enough that a low resistance is required, to avoid a voltage drop at the switch that will, for example, reduce the output of a light connected to the circuit.

If you dismantle a household switch, you'll usually find contacts that work like a pair of hands clapping - quick to make or break, but not very good contact. In contrast most 12v switches use 'wiping' contacts (just like the exposed switches in Dr Frankenstein's lab!) where the wiping action keeps the contacts clean and so lowers resistance.

Now this is the situation here in Yurp where we use that scary 240volt electricity - maybe an American expert will tell me that 110volt switches don't work that way, though I bet they do.

You are correct that is why the switch is labeled 120VAC only! The sine wave of AC helps extinguish the arc on making or breaking the switch
Applying DC to an AC rated switch does not work well and a waste of money. You can buy AC /DC rated switches for less than 20 bucks