I've installed a battery operated door bell. I've checked that I didn't nail a clip into existing cables so why does the door bell ring when I switch on the kitchen light?
The kitchen light (flourescent) has always hummed and buzzed but someone here said that was probably the choke?
So, why does my doorbell ring?
what route does the flex take from the bell push to the bell unit? If it is in close proximity to the light it could be that on start up the light is inducing a current into the flex and causing the bell to ring.
If it is a good, old-fashioned, "mechanical" doorbell with a striker and either a couple of plates (ding-dong) or a dome (ding, ding ding ding):
Then there is no way it should be ringing. It must have some form of electrical connection to the house mains wiring and you do need an electrician to sort it out.
If it is a new-fangled "electronic" doorbell with a loudspeaker:
Then it is possible that the wires going to the bell button are acting as an aerial and pick up "signals", such as electrical switching. The earliest radio transmitters consisted of a switch and a coil - very much like the starter and the choke in a fluorescent light fitting. Even more so if the fitting isn't earthed.
So, as Dave suggested, it could be that the bell wires are running close to some of the light wiring. Now most house wiring runs the supply wire and the return wire in the same cable - which greatly cuts down the "signals" it can radiate. The exception is light switch wiring, which normally takes a supply wire down and a supply wire back, in the same cable. So, running an "aerial" close to that cable can pick up stuff.
What to do?
I would suggest switching off the power at the consumer unit and then have a look at the electrical connections to the light fitting and make sure it has an earth connection (it could be a double-insulated one that doesn't need an earth but they are very rare, IMLE). Fixing the earth problem, if there is one, will typically much reduce the electrical noise produced by the fitting and may stop the bell ringing.
Fixing the earth problem, if there is one, will much reduce the possibility of an electric shock - say if you buzzing choke does have/get a fault such as the fitting goes live. Next time you clean the thing with damp hands, standing on metal steps.. yow. So worth fixing.
Failing that, maybe it is time to replace that old light fitting, anyway?
Or, if you want to keep the bell and the existing light fitting and it has a good earth and you don't want to rerun wiring:
Go to Maplins or equivalent and buy a 1uF 25v (or higher) non-electrolytic capacitor and connect it between the two wires going to the bell push - but at the bell box end. What this will do is remove most of any "signals" that may be picked up by the wiring. The bell push will still work (the bell may keep still ringing for a fraction of a second, or even a second or two, after the bell push is released, though). This will work in many cases, but I can't promise it will work in yours.
The only thing I could add to that is there should be a suppression capacator on the flourescent light. If that is faulty or not properly connected it may cause a problem.
The first thing to do IMHO is to check that the lighting cable carries an earth wire.
Adam
Is this a wind up?
Did the last doorbell ring?
Take the starter choke out of the flourecent light and try the switch again? obviously the light won't come on but we're doing a test,if nothing then change the starter choke for elimination purposes.
It isn't by any chance a wireless doorbell?
With cable running from bell push to bell...I doubt it.
it's a wonderful novelty, had you thought of marketing it?
my first tv with a remote worked on sound rather than light and you could change channels by sneezing
Many thanks for the advice. I'd suspected some sort of dodgy wiring. I've re-routed the bell (a new electromagnet type) wire and found the bell rang of its own accord with an open circuit. I took out the batteries and re-inserted after 10 minutes, now the bell rings as its supposed to when the bellpush is pressed - the only thing touched were the batteries. Wierd.
This capacitor would stop all of that would it? I assume you meant connect it as close to the actual bell as possilb? Again thanks to both of you for the advice. Andy
There is no way that a purely non-electronic bell circuit should pick up enough induced energy from mains wiring to ring the bell. Wierd doesn't describe it. Electromagnets work on current. Whilst you might induce a high enough voltage in a wire to trigger a semiconductor device, you aren't going to induce enough current to energise a solenoid. In fact, you have no current, with the bell push switch open, no current can flow.
A capacitor would help with an electronic bell, as the capacitor acts like a short circuit to any transient voltages travelling up the bell wire, and stops these voltages triggering the bell electronics. It is put as close to the electronics as possible - to stop any possibility of voltages being induced in the wire between capacitor and electronics.
It isn't going to make any significant difference to a pure electromagnetic bell at all. It won't do any harm though.
I'd be having a closer look at the bell - the only realistic way the bell could operate off electrical noise with an open circuit is if they have put a bit of electronics in for some reason - eg to reduce the current in the bell push to make it last longer, to commutate the coil (eg repeatedly ding-dong whilst the button is pressed, rather than one ding and one dong etc.
It is not a wind up at all. That's why I asked in this newsgroup for advice.
Thanks for the useful and not so useful advice. I checked the wiring and it was all over the place though earthed. Having re-wired, the bell rings in tone with the light starting up. Its now in the bin replaced by an ordinairy bulb. Problem solved.
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