How to disconnect bell chime from transformer

[-JohnnyBoy-]

Hello all

I'd like to remove the bell chime from my hallway prior to decorating and struggling to work out how. It's connected to a transformer, which is under the consumer unit. Pics of both attached.

First question is - when I flip the breaker for the bell to off, my voltage detector is still detecting voltage at the bell chime (no batteries that I can see) but not at the transformer itself. Why would that be?

More generally, how do I go about disconnecting the chime from the transformer and is it safe to leave the transformer connected to the consumer unit after.

I was planning to open up the transformer to grab a pic of the wiring but I've been put off because the chime still has a current and not sure why or what that means.

Thanks!

 

[opps]

Which kind of voltage detector are you using?

Your transformer is rated at 8v-24v.

Just mark the cables and remove them. Wrap some electrical tape over the ends and remove the chime.

Something very freakish would have to happen for you harm yourself even if the wires were sill live.

 

[-JohnnyBoy-]

Just a basic pen voltage tester
https://www.screwfix.com/p/lap-ac-non-contact-voltage-detector-pen-1000v-ac/3222G?tc=AA8

Are you saying I should ignore the transformer? So flip the breaker off, remove wires from chime, wrap in tape and leave them in the wall, remove chime and turn on breaker?

 

[ericmark]

Interesting, I will go and test with mine same idea but more expensive. Unlike yours it has 4 bars to show how much non contact voltage it has detected, and the bleeper has 4 different rates, tested a LAN cable as yet not connected to anything and got a single bar, on a switch it was showing 3 or 4 bars, but it does pick up any voltage due to wires which have power running in the same direction. My lap top shows 2 bars, and it is powered with a 24 volt supply. Getting full 4 bars on a USB lead.

I find it handy as can test a switch or socket before removing any screws to get at terminals to use leads, but it is clearly just an indication, and needs re-testing once you have access with a contact tester.

I agree with @opps seems unlikely you could get a dangerous voltage even if still energised. I would just put some tape over the wire ends to be on safe side.

 

[opps]

Just a basic pen voltage tester
https://www.screwfix.com/p/lap-ac-non-contact-voltage-detector-pen-1000v-ac/3222G?tc=AA8

Are you saying I should ignore the transformer? So flip the breaker off, remove wires from chime, wrap in tape and leave them in the wall, remove chime and turn on breaker?

I would recommend turning off the transformer, not for your own safety but to make sure that you don't run the risk of wires touching each other whilst you dismantle it- wires touching each other could fubar the transformer.

I too own a non contact voltage pen. I find them to be extremely useful, but they often give me false positives- meaning that they tell me that there is a current, when there isn't. IMO a false positive is wayyy better than a false negative. A £5 multimeter will, potentially, be more reliable.

Again though, in the transformer, the cables running to the chime will be connected to the 8v side, 12/15 or 24 (or increments in between). Regardless, if you touch any of the cables you are very unlikely to notice that you have done so.

 

[EFLImpudence]

I too own a non contact voltage pen. I find them to be extremely useful, but they often give me false positives- meaning that they tell me that there is a current, when there isn't. IMO a false positive is wayyy better than a false negative. A £5 multimeter will, potentially, be more reliable.

Just to say - they do detect Voltage; not current.

 

[opps]

Just to say - they do detect Voltage; not current.

Far play. Thanks for correcting me.

 

[-JohnnyBoy-]

Thanks for the replies.

This morning I switched the electricity off at the main switch and removed the 2 wires from the 8v side of the transformer. Flipped the electric back on and my voltage detector is still detecting voltage at the chime and also worryingly at the 2 wires I removed from the transformer. The breaker for the bell is also for the heating.

Any ideas what's happening here and how I should proceed?

 

[Harry Bloomfield]

Any ideas what's happening here and how I should proceed?

It could just be as simple as 'pickup' - an induced voltage from another circuit, which is live and runs in close proximity to your bell wires.

 

[opps]

Thanks for the replies.

This morning I switched the electricity off at the main switch and removed the 2 wires from the 8v side of the transformer. Flipped the electric back on and my voltage detector is still detecting voltage at the chime and also worryingly at the 2 wires I removed from the transformer. The breaker for the bell is also for the heating.

Any ideas what's happening here and how I should proceed?

I have two voltage pens- a Fluke one and a Amazon cheaper chinese one.

The cheapo one will indicate voltage if it detects a screw in a stud wall that has no cables in it.

Again... they will often show false positives. That said, a false positive is better than a false negative.

I, respectfully, think that you are being excessively cautious.

You have turned off the main breaker, if you believe that your main breaker is less reliable than than your voltage pen, then it might be prudent to spend a few hundred quid for an electrician to turn up...