Multiple doorbells - need a bigger transformer!

[sparkybird]

Hi everyone

It's Friday - hurrah!

I've been asked to install 4 doorbells (on the same push) in a large house. Rather than installing a transformer per bell, I'd like to just have one. These are the bells (buzzers) I'm thinking of

http://www.tlc-direct.co.uk/Products/VE792.html

I'm thinking then that I need a transformer with a min output of 4A and 8-10V. Do these exist?

I see that the normal bell push is rated at 2A, so won't be suitable. I was thinking of one of these which is good for 10A

http://www.tlc-direct.co.uk/Products/MKK4848B.html

Then finally I need some chunkier bell wire - not sure what bell wire is rated at? 1A maybe? Could I use speaker cable? How do I find out the rating of this?

Hopefully someone will come to my assistance. Any suggestions for alternatives (NOT wireless though) also welcome

Many thanks

SB

 

[sparkybird]

Maybe this for the tranny?

http://uk.rs-online.com/web/p/chassis-mounting-transformers/0504000/

I'd need to put it in a box though!

SB

 

[Taylortwocities]

This was discussed at some legth a short while ago.

See //www.diynot.com/forums/viewtopic.php?t=278545&start=0

Somewhere near the start I've posted the current-carrying capacity of bell wire.

The standard bell wire is
1/0.6mm copper 22AWG (23SWG)
The maximum is 1.8amp.
For 3amp you'll need to use something like 0.75mm² twin cable. And that will include the wires to the bell push..

You are probably OK with that tranny, but you will need an insulated container for it..

Friday yaaayy, and its BEER O'CLOCK!!! Byeeeeee

[/quote]

 

[JohnW2]

I've been asked to install 4 doorbells (on the same push) in a large house. Rather than installing a transformer per bell, I'd like to just have one. These are the bells (buzzers) I'm thinking of
http://www.tlc-direct.co.uk/Products/VE792.html
I'm thinking then that I need a transformer with a min output of 4A and 8-10V. Do these exist?
I see that the normal bell push is rated at 2A, so won't be suitable. I was thinking of one of these which is good for 10A
Then finally I need some chunkier bell wire - not sure what bell wire is rated at? 1A maybe? Could I use speaker cable? How do I find out the rating of this?

I would be inclined to ask Friedland how much current that bell really takes. It's presumably less than 0.5A, since one of the transformers recommended ('743') is only rated at 0.5A - but I suspect that it could actually be a fair bit less than that - so it might be possible to run four bells of, say, a 1A transformer (like their 'TR7'). A 2A bell-push should certainly be OK, and so quite probably would be ordinary bell wire.

Kind Regards, John.

 

[Lectrician]

What sort of lengths are the cable?

We had to revise someones install in a large B+B a while ago.

A few bells on a run of 0.5mm flex. Pressed the button and you got a 'tingk' and the voltage fell to nothing. They had run a couple hundred meters of cable though, a mix of bell wire and flex.

 

[sparkybird]

Thanks for replies folks

TTC - Oopps, forgot about searching the forum.... sorry. Don't fancy wiring it in 2 core flex as a lot of it is surface... But if I can find out the current rating of speaker cable, could I not use that? Can you point me in the direction of current carrying capacities of bell and speaker wire??

John - good point - no info on the product, but I will, call to find out. Alternatively I could try and find a bell/buzzer that is 0.25A...

Lectrician - it's a large house, 3 storeys, so we're not talking miles of cable.

Thanks for your time everyone

Its now officially G+T O'clock!

SB

 

[big-all]

normal bell wire control circuit controlling 2 relays for 2 independent bell circuits with 2 bells on each

or buy 2 off these and make sure they are all on the same frequency
http://www.ebay.co.uk/itm/Twin-Plug...arden_Door_Accessories_LE&hash=item3a677ed83a

mines works brilliantly in the shed no wiring required as they plug in with a battery in the bell push

 

[sparkybird]

Hi Big all

Customer adamant that he doesn't want wireless as he's had interference problems.

He wants 1 push only to ring 4 bells - so not sure that the relay idea would work? More info please....


Thanks

SB

 

[RF Lighting]

Yeah it would work fine.

Send a live or +ve from your transformer to the bell push.

The switched live from here supplies one side of the coil on your relay.

The other side of the coil is connected to neutral or -ve

Then supply the common on the relay with whatever power you want to power the bells with. You could even use mains if you want.

The bells live connection connects to the normally open (NO) terminal on the relay.

The neutrals go back to the circuit or transformer neutral connection.

You can wire each bell back individually, or loop one off another or any combination in between that you like.

You can use this to swich as much load as the realy or the power supply is rated to.

 

[Stoday]

Yes, you could use speaker cable. Make sure it's a quality cable though, such as the following:
Click

OK, it's only 8 ft long, but you could connect a number in series.

 

[Taylortwocities]

 

[JohnW2]

normal bell wire control circuit controlling 2 relays for 2 independent bell circuits with 2 bells on each

I really don't think relays would help the OP - they would merely complicate and confuse the issue. It would only really become a useful approach if he wanted to use a relay to switch mains power and pipe that around the house to power supplies local to each bell (to avoid voltage drop problems with 8-10V wiring) - something (mains cable) he has already said he doesn't want to do.

Kind Regards, John/

 

[JohnW2]

John - good point - no info on the product, but I will, call to find

One thing to bear in mind, which others have hinted at, is that the main potential problem with the wiring may well be voltage drop, if the lengths of wire is long - such that not enough voltage might get to the more distant bells for them to operate satisfactorily. This is likely to be more of a potential issue than the rated 'current carrying capacity' of the wire. If you can find out what current the bell actually takes, and over what range of voltages it will operate, we ought gto be able to work out for you what sort of wire/cable should be necessary.

Another thought/question - are you commited to 'bells'? Some of the solid-state 'sounders' around use very little current.

Kind Regards, John.

 

[Alarm]

Really........If he wants 4 bells and you have to run cable. (have to admit skimmed this thread). You can have a 2 wire video entry system.

And it will run on "bell wire"

Just my penny worth.

 

[ericmark]

I bought some speaker cable and tried to solder only to find one core not copper. Seems very like temperature compensated cable. So I would not use speaker cable for anything other than speakers.

Using any flex we are limited max (Table 52.3) to 0.5 for "Signalling, and Control Circuits" and most other to 0.75 so likely one can't get less than 0.75 flex which is rated at 6A.