Finding a hidden transformer

[mozzo]

A client has 6 x SELV downlights running from a single transformer that is buried within the fabric of the building (ceiling, I guess).
The client has no idea where the transformer is and I will need to find it. Naturally there are a number of problems and a number of test that could be performed to try and locate the transformer depending if an electronic transformer or toriodial is used and whether the 12v lights are wired in a star from the transformer or if there is a single run of cable from the transformer looping to each light.
I am just looking at doing low ohm meter reading to identify the closest light point to the transformer and maybe a EMF dectector before opening up the floor boards or ceiling to look around.
Anyone got any other technique that you would like to share? Thanks

 

[malcolmsanford]

 

[mozzo]

I agree, it's looking like "hammer time" or has someone got some Xray machine for hire.

 

[UNG]

Use a cable locator / tracer on the circuit. Trace back from the fittings should be able to find the common point that is the transformer

 

[spud1]

Might be a bit over the top but you could borrow/hire a thermal imaging camera from someone or use the good old fashioned flexible mechanics torch and dentists mirror and peak around the corners of the spotlight apetures?

 

[telectrix]

inspection camera might come in useful here.

 

[kathwilcox]

If you drop all the fittings down that should give you an idea of how they are wired, and also an idea of where the transformer is.
Also small hands an skinny arms help!

 

[GT1]

Super Rod do an inspection mirror to fit their rods and it comes with a flexible fitting too.
Can defo recommend it. Saved me loads of grief looking in ceiling voids AND much cheaper than a camera.
(you just need a torch)

 

[mozzo]

Thanks for the alternatives but cannot see how the cable tracer will work in this situation. Those devices with a long tube and light with a hand held camera at the end similair to key hold surgery instruments or checking inside drains would be the thing to use. Drill small holes in the ceiling and poke around. There is always a better tool to use, but the problem is, is it worth the investment to buy such tools for one off use. Will check out super rod

 

[UNG]

Thanks for the alternatives but cannot see how the cable tracer will work in this situation.

Drop all the fittings put the remote unit on each of the cables and trace it back all cables will / should merge at one point the transformer. You could try a stethoscope on the ceiling and listen for the transformer hum

 

[telectrix]

philistine. use this

 

[mozzo]

I see what you are saying, makes sense but have not used one of these cable tracers but can the receiver pick up a signal through plaster board and at what distance.
The ones that edf use to pick up the incoming armour cable seems to have the strength to pick up about a meter down but that must cost a far wack. I believe the lesser ones are around £160, far too much for a one of exercise right now.

 

[UNG]

Without being prepared to make the investment in tools and equipment then you are down to an educated guess and ripping the floor boards up

 

[needasparks]

I guess looking for the cut traps upstairs is too obvious to say but you could stamp the floor giving an idea of loose flooring as others have said just pulling all down should shed light on it then its down to how lucky you feel with a pad saw. sometimes giving them a tug you will hear the transformer dragging on the ceiling.
As always with these diy sunday afternoon self fits you have to use your best judgement before damage is made, if nothing else with the lights out you can mark all the joists and then ---- a coin and let the customer call heads or tails.

 

[Guest111]

I have one of those camera,s if your near me I could lend it to you.

 

[needasparks]

Without being prepared to make the investment in tools and equipment then you are down to an educated guess and ripping the floor boards up

You are of correct there. No one really likes spending money but with things like that they are priceless when fault finding and on inspections. I bought my camera about 5yrs ago for £150 and its paid for itself more times over than i can remember.

 

[Marvo]

I like the cable tracer idea. I have one that will work to locate cables buried up to 1 meter and you can adjust the sensitivity etc. I'm sure it would work at least up to the transformer.

 

[needasparks]

Buried upto a metre ? are you sure ? Buried in what ? custard !

 

[imago]

Buried upto a metre ? are you sure ? Buried in what ? custard !

Going by how the roads sink after cables have been run I think that's what they use with about 10mm of tarmac over the top.

 

[needasparks]

Going by how the roads sink after cables have been run I think that's what they use with about 10mm of tarmac over the top.

Now you have said that, I may be thinking of something completely different like one of them light pen things.

OK, I'll get my coat !!!!!!

 

[alarm man]

Drop all the fittings put the remote unit on each of the cables and trace it back all cables will / should merge at one point the transformer. You could try a stethoscope on the ceiling and listen for the transformer hum

is it serious doc??

no sir you just have a bad case of transformer hum.i'll give you a good whack on the back that should sort it.:ihih:

 

[Marvo]

Buried upto a metre ? are you sure ? Buried in what ? custard !

http://www.instrumentsgroup.co.za/index_files/Fluke/2042,CableLocatr.pdf

They say it's good for up to 2.5 meters but maybe thy did get that depth in custard. It does work well up to around 1 meter, much deeper than that it becomes more art than science and it's a bit hit and miss.

 

[alarm man]

found it!!!!!!!!!!!!!!!!!!!! :coolgleamA:

 

[Snapester]

Where was it!