Bell wire and transformer

[DetlefSchmitz]

I think 333rocky333 was closest. I tried fitting my own setup with a 10m run of bell wire and the bell did not ring. I then checked the resistance of the wire in question and there was no way that it was going to work because of the voltage drop. With twin and earth it would not have been a problem, but as I was busy and the need for the bells was urgent I got a couple of wireless bells (one for upstairs and one for down). It was clear from measurements that, if I'd had time, some 1.5mm twin and earth would easily have solved the problem.
For the record, the wireless bells have functioned perfectly.

 

[Iggifer]

Cost is not a consideration as my whole setup wont be more than £200 and bell wire probably only £50 for a roll.

If you are using bell wire, which may not be the best cable for the job, ironically. It’s more like £5 a drum, not £50. Don’t get ripped off.

Some 14 strand speaker cable might be meatier enough to help out without going silly big and visually not massively different to bell wire

 

[ban-all-sheds]

I'm sitting here wondering what the problem is with having 3 off-the-shelf wired doorbells going through one bell push?

Might need something other than an actual door bell switch if the contacts have to carry the current for 3 sounders, but it wouldn't be hard to find something suitable.

 

[ban-all-sheds]

there maybe a problem if the third bell is very close to the transformer as there will be less impedance, and so it may get most of the current.

Errr....

Really?

 

[john4703]

I was wondering why not have a bell push rated for 230 volt and three transformers, one next to each bell. Do it all in 1mm T&E and volt drop is negligible.

 

[ey143]

If you are using bell wire, which may not be the best cable for the job, ironically. It’s more like £5 a drum, not £50. Don’t get ripped off.

It probably was £5, I honestly can't remember I just threw a figure out there.

 

[Taylortwocities]

£6.80 for 100m. Screwfix

 

[ban-all-sheds]

I was wondering why not have a bell push rated for 230 volt ....

You'd need a switch other than a "normal" bell push, and you'd have the problem of routing cable that size to and from. ELV switches and bell wire are attractive because the cable is so small that it can be unobtrusively run along the tops of skirting boards, around and through door frames etc.

But people cope with installing much larger cables for outside lights and sockets and switches, so why not?

Particularly as

I'm renovating my house ... I'm at a building stage in my project to running cable around will be a doddle ...

 

[ban-all-sheds]

Not sure why I've only just wondered what's wrong with this picture...

I want a wired bell option since I don't fancy recharging any units or changing batteries or having interference issues
.
.
my home will have various zwave automation relays etc built in...

 

[bernardgreen]

I want a wired bell option since I don't fancy recharging any units or changing batteries or having interference issues
.
.
my home will have various zwave automation relays etc built in...

Not sure why I've only just wondered what's wrong with this picture...

Maybe ey143 is aware that the more wireless devices there are in his house the higher the risk that communication from door bell push to door bell sounder will be compromised by transmissions from other wireless device in the house.

 

[bernardgreen]

I was wondering why not have a bell push rated for 230 volt and three transformers,

A shocking idea unless one used an IPx4 or better bell push.

Bell push operating a relay to switch the ELV supply is the better option.

If the cable runs are really long then use a transforner with an output voltage that is equal to the minimum voltage required at the bell plus the voiltage drop along longest cable. The current capacity nust be large enough to drive all the bells.

If with that set up the bells on shorter cable runs are over volted then add resistors in the cable runs to those bells.

 

[Iggifer]

A shocking idea unless one used an IPx4 or better bell push.

This. Plus, it's discrete

 

[ban-all-sheds]

A shocking idea unless one used an IPx4 or better bell push.

Bell push operating a relay to switch the ELV supply is the better option.

Have you never seen outdoor LV switches, sockets, etc?

 

[Echo the husky]

Definitely over thinking this, a decent 2A bell transformer, a bell push and 3 bells, buzzers or whatever, avoid 'bell wire' it's not good, we use 0.5mm² 2 core oval flex for most doorbells as it's far more robust and there are fewer problems with voltage drop. For a larger setup 0.75mm² or 1mm² 2 core flex or will likely be more suitable.

I'd wire each bell and the push back to the transformer and make the connections there. I have also over come volt drop problems with a pair of bells by connecting the local 8V bell to the 8V transformer tap as designed, and the second remote 8V bell to the 12V tap, with the bell push wired to the 0V terminal.

Another option if the wiring will be very long is to use 3 bells with self contained mains transformers, then an ELV circuit where the bell push operates a small relay in each of the bells in place of a bell push.

 

[winston1]

I have also over come volt drop problems with a pair of bells by connecting the local 8V bell to the 8V transformer tap as designed, and the second remote 8V bell to the 12V tap, with the bell push wired to the 0V terminal.

So that means when the the bell push is not pushed the 2 bells are in series across 4 volts between the 8 and 12 v taps. Not good.