Powering a foreign wall clock

Oct 16, 2015 11 Replies

Friend has acquired an illuminated wall clock. Came with an 12v 1000mA wall wart adaptor.



It's hung on a stud wall and the wallwart wire drapes down untidily to a socket below.



Other side of the stud wall (or technically within it) are 2 light switches and an isolation switch for a cloakroom extractor fan.



It would be very nice to power the clock somehow from the mains in the wall or through the wall iyswim.



Clearly a 240/12v transformer is required but what possibilities are there for powering it from the existing wiring in the wall before presumably poking the wire through the skins of plasterboard to the rear of the clock....



TIA



Jim K


Well the fan isolator will have a permanent live and neutral. So where do you want to hide the transfomer?

Obviously you can put the wall wart on the other side of the wall and the cloakroom extractor circuit will be man enough to power it. Whether you can do it within regs is another matter. Presumably the wall wart has a foreign pin configuration so even if you found a socket to fit, you possibly can install it within regs. If you bought a UK one it would have 13amp pins on it but I doubt if a

13amp socket can be installed on the fan circuit even if correctly fused. you could fit a 5amp socket but possibly not get a match wall wart. If it were mine I'd just do it but it is up to your friend and his attitude to compliance with regs.

/Well the fan isolator will have a permanent live and neutral. So where do you want to hide the transfomer? /Q

Indeed:-)

How about "hiding" the transformer in a double plastic pboard backbox, with a blanking plate on the front, 12v output out the back of it through the rest of the stud wall to the clock?

Cheers Jim K

Is the output of the "12V 1000mA wall wart" AC or DC? If the latter, a 240v/12v transformer is unlikely to give satisfaction.

How about using something like this?

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No reason it can't go off the cloakroom extractor circuit if mounted with sufficient ventilation?

It might over heat? maybe some slots in the cover plate would be a good precaution.

I think you firstly need to find out what current is needed for the clock. Personally I'd not use a switch mode supply, they seem to often kick up if presented by any kind of inductive load. You also do not say if its a/C or D/C. Some years ago I came across an analogue wall clock th at ren on 24v A/C but it was always slow when powered up here in the UK, suspect it expected

60 hz a/c. Sounds like you need a very slim line mains adaptor or if the clock has room buld one inside its case. Without more details its hard to advise.

Brian

If you get a power supply which runs cool as its over rated, then it might not matter as per some Halogen lights etc. Brian

If the "UK socket" was labeled up as "clock only" then it complies with the regs even when powered from a lighting/fan circuit.

Common sense prevails then - good to see!

Sounds like a job for an angle grinder:-)

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