240v buzzer on a 3 gang sw

[sparkybaz]

stumbled on this site by accident while looking to solve my problem.
as a spark of 25 yrs finding the topics very interesting and i hope to be able to contribute in the future.

ive a 3 gang switch that acts as an overide for 3 outside security lights,i want to fit a buzzer so if either or all of the lights are left on using the overides it can be heared as an audiable warning.how can it be done so as not to give a backfeed and put all 3 lights on when only 1 switch is closed.
can it be done by fitting a diode on the 3 switch wires feeding the buzzer or an i thinking on the wrong tracks.

cheers all

 

[Shakey]

presumably you have neutrals at the switch then?

If so, i would fit a small bridge rectifier across each sw/phase and N, each output from the three bridges can be lined to feed a DC buzzer

If you dont have a neutral, dont see how you can do it, because connecting betwen phase and CPC would not be acceptable

 

[Spudmiester]

Have a solution but it depends on the wiring. You say its a three gang switch just used for overide, so what you could do and its a bit 'industrial' but would work, is from th l2 connection of each switch (the l1 being used to switch to overide) is take a feed to the coil of a small relay and switch the buzzer through that. You would need three relays, with the common and normally closed of each relay wired in parallel.
When the switches are in the non overide position, all coils will be energised therfor silencing the buzzer. If any switch is then switched to overide the coresponding relay will de-energise and switch on buzzer !
Like I say it depends if you can get some more wires to the switch, and like Shakey said, you need to pick up the correct neutral, but if you could get at the wiring, and house all the relays in a proper enclosure somewhere it would work. The only problem would be one day if a coil burnt out then the buzzer would sound all the time,it does happen but modern relays are pretty long lasting.

I would do a drawing but am not much good with computers, so hope this helps !

 

[Shakey]

Have a solution but it depends on the wiring. You say its a three gang switch just used for overide, so what you could do and its a bit 'industrial' but would work, is from th l2 connection of each switch (the l1 being used to switch to overide) is take a feed to the coil of a small relay and switch the buzzer through that. You would need three relays, with the common and normally closed of each relay wired in parallel.
When the switches are in the non overide position, all coils will be energised therfor silencing the buzzer. If any switch is then switched to overide the coresponding relay will de-energise and switch on buzzer !
Like I say it depends if you can get some more wires to the switch, and like Shakey said, you need to pick up the correct neutral, but if you could get at the wiring, and house all the relays in a proper enclosure somewhere it would work. The only problem would be one day if a coil burnt out then the buzzer would sound all the time,it does happen but modern relays are pretty long lasting.

I would do a drawing but am not much good with computers, so hope this helps !

Spud, good idea, but why not use the normally open contact, so the buzzer does not stay on if the relay fails?

 

[Spudmiester]

Know what you mean Shakey, and did think of that. I am assuming you mean use n/o contact and energise the coil directly from the l1 when the switches are in overide .
The reason not to is because when the security lights PIR detector pics somthing up and switches th lamp on it would backfeed down the overide wire and energise the relay, making the buzzer sound every time somthing is detected.

 

[sparkybaz]

thanks for the replys,i think ill end up going down the route of the new style gjd controller ,12v pirs,digital display with more functions than you can remember and can record a 10 second message which is played after a preset time.
imagine the wifes face when it says "youve left the lights on again you dumb b*tch"

going down this route a very nice piece of kit
DygiZone lighting controller