Low Voltage Lights

Hi All

Customer asked me if I could find out why her low voltage lights weren't working properly.

They were on a two way switch circuit. Stuck my fairly basic multi meter on both switches. To my surprise I got 12v on each switch.

I would have thought that each switch would be 230v and would have powered up the transformer? It seems that the switches are working on the 12v side. Is this common or indeed the right way to wire up low voltage lights on a two way circuit?

Reply to
The Medway Handyman
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No it's not normally done that way. The switches may not be rated for enough current on the 12V side. The extra cable length to switch and back will drop precious volts. The transformer is presumably on all the time. Some electronic ones will shut down if there isn't enough load on them and not restart until the supply is interrupted.

Reply to
Andrew Gabriel

Not the way I've seen them wired up.

I've always seen them wired with the switching on the 240v side, as you expected.

The low-voltage side has correspondingly higher currents. Why would anyone intentionally run these high currents through the additional wiring length to the switches, and also expose the switch contacts to high currents to interrupt?

Seems wrong to me.

Reply to
Ron Lowe

Its not the best way to do it in most cases, though there will be exceptions where it is. Just saying dont assume it must be rewired, it might have worked fine that way, and continue to once the fault is fixed. OTOH it may be that the transformer min load is not being complied with, or the swiches are seeing above theur rated current.

NT

Reply to
meow2222

I'm struggling to think of any myself!

David

Reply to
Lobster

Oh... if both switches are underwater I'd say it was a good idea.. ;-)

Reply to
The Natural Philosopher

Doing it this way and assuming 1mm cable, the cable will overload on 10 spots each drawing 1.6A (20w/12v) table 4D5A IEE regs

Reply to
bob watkinson

First I'd want to be sure it's a true 12 volts and not just some form of coupling.

But if it is, it's not a good idea. Excessive voltage drop on the cable and a permanently 'live' transformer. Also if more than 60 watts you're probably exceeding the load for the switches.

Reply to
Dave Plowman (News)

yeah especially with the cheap light switches only rated at 6A. The better ones are rated at 10A but still less than the cable itself.

Reply to
bob watkinson

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