12v Camper Electrics

[SUNRAY]

Would that be the method where both ends of a switched off light can be live ?

Yes Example from last year:

This was a very old office with some recent additions, I've added the green circles where the 2 sets of L&N enter the system. ignore the filing room lamp and switch as it was wired wrong (that was the fault and the reason I was looking).

 

[bernardgreen]

This is NOT a good idea. An intermediate switch can put transient short circuit across the strappers as it is switching.

In your diagram this could be a short between L and N

 

[ericmark]

It actually works fine as long as the load is connected to common. Doing that with domestic lights would probably cure all the glowing/flashing lights problems people report !

This is DC there is no transformer effect, or capacitive linking, there is simply positive and negative, the switches used take a high current and low voltage and you can select break before make.

It is common to borrow negatives and with auto electrics in a caravan the chassis is not used as a return, it is with a car, but not a caravan, as said any switch with a indicator built in must have a negative to the switch.

It may be called an intermediate switch in domestic electrical systems, but it's a reversing switch with auto electrics, so the leisure battery will be likely charged from either an inverter or charge relay or blocking diode, the latter two means it will be linked to chassis as it only switches the positive, the inverter will isolated the leisure battery from the prime mover battery.

The 12 volt spot lights are not really 12 volt, you need a DC bulb which will have a voltage range 10 to 30 volt in the main as when engine is running voltage can be 14.8 volt more normally 13.8 volt it depends if a stage charger is used. So bulbs from suppliers like these as designed for vehicles and boats, most the "cheap" LED MR16 spot lights I have bought from likes of screwfix or Lidi are marked 50 Hz and not suitable for powering from a battery. They required 12 volt not 13.8 volt.

I have found with caravans a lack of cables means you can't use switches with indicators built in as no negative to switch, and the radio does not have a permanent positive to retain memory so the car type radios can auto switch on to demo mode when plugging in car. You have to be careful what you select, caravan forums will help, as with canal boat forums as they have members who have had it all before, and will tell you what make of switch or light to buy.

 

[SUNRAY]

View attachment 172556

This is NOT a good idea. An intermediate switch can put transient short circuit across the strappers as it is switching.

In your diagram this could be a short between L and N

This is not something I've ever encountered, and i've quite often seen standard intermediate switches used to reverse 3ph or DC motors.

The only problem encountered in the above system was the 'Filing Room' didn't always work (Moving the brown wire from the intermediate switch to the brown/red junction resolved it).

 

[JohnW2]

This is not something I've ever encountered, and i've quite often seen standard intermediate switches used to reverse 3ph or DC motors.

Same here, and given that they cannot know for what purposes they might be used, I would be surprised if manufacturers (at least, 'responsible' ones) would make intermediate switches which potentially suffered from the issue which Bernard mentioned.

Kind Regards, John

 

[SimonH2]

I agree, it would be a very poor design if it did short. But cheap manufacturers ...

 

[SUNRAY]

Would that be the method where both ends of a switched off light can be live ?

just for the record, another example of the system:
https://www.diynot.com/diy/threads/2-way-lights-again-oh-and-why-i-dont-like-domestics.513146/

 

[SimonH2]

That's the setup I had in mind.