8/12v bell transformer Ask questions and find answers to many subjects relating to electrics and electrical work

[Sandtree]

We’ve a wired doorbell and looking to replace with a smart option like the Nest Hello,

Our current transformer is in our Square D consumer unit and unlike most appears to support both 8v or 12v (the latter being the minimum requirement for Nest).

Without taking the front off the CU i cannot see which way its currently wired but looking in the chime all the wires (4 in total) are exceptionally thin. Given the amps reduce on 12v (transformer is 8va with either voltage) will the wiring be suitable to change the voltage if required?

Many thanks

[Mr White]

From what I have previously read regarding so called "Smart doorbells" I would say that your current transformer is too small* People in your situation have upgraded the transformer with no further problems.
On the assumption you have standard "bell wire" and you are only going to send 24v maximum down it, I envisage no problems.

[Sandtree]

Many thanks

Ring have said it would work fine with their Ring 3 device which doesnt have as higher power requirement because its not doing 24/7 recording and is battery powered with the wired mains power used to charge the battery.

Nest say that the minimum in Europe is 12v and 8va and so in theory if the existing transformer was connected with pole 4 it would work but only at the minimum (though their website gives a lower voltage requirement if measured by a voltmeter than what they require printed on the transformer)

I was slightly concerned with changing the transformer up to 12v (but down in amps) due to having not seen such thin wires before as there are in the existing chime but if its ok I can give it a go as the Nest option is just so much better than Ring which is massively oversized due to the battery pack in it.

[Sandtree]

From what I have previously read regarding so called "Smart doorbells" I would say that your current transformer is too small* People in your situation have upgraded the transformer with no further problems.
On the assumption you have standard "bell wire" and you are only going to send 24v maximum down it, I envisage no problems.

Thanks for your help.

Managed to attach a Nest Hello and thankfully it went straignt to a blue light (yellow warns of low but acceptable power). However our mechanical chime doesnt work now. I understand electronic chimes work on a lower power but there dont appear to be many and the Honeywell one at least needs a third wire for a continuos power supply. Are there any low lower, two wire chimes i can run on 12v ac?

[Mr White]

If you are saying you have a nest hello and a mechanical doorbell on the same transformer, I am not surprised it does not work, the transformer is too small.
If you are asking do I know of a doorbell that will work with your new set up, I can only suggest that as "I do not work with doorbells all day" (So I have no knowledge of specific doorbells) you try a search engine.

For what it is worth, I understand the principal of "video doorbells" but I fail to see the benefit, as more often than not by the time your chosen device has connected to the internet, notified yourself, then you have taken your phone from your pocket, logged in, the caller will have gone.

[Sandtree]

As someone who doesnt have a smart phone I somewhat agree but the Mrs wanted a better view of whos at the door at night than the small hole in the privacy film gives plus the ability to talk to a delivery person when shes on the 2nd floor (by the time shes at ground theyve normally gone).

May also catch the animal thats been digging up our front garden at night!

I think ive found a Honeywell device that can be triggered by the AC/button but sounds using its own batteries so should do the trick.

[Sandtree]

PS. On her phone at least its ubder 5 seconds from button press to prompt appearing and video showing

[ericmark]

Quick internet read and I find:-

Does Nest doorbell ring on Google Mini?
The Ring supports additional chimes so you can hear the doorbell around the home, but the Nest Hello doesn't. ... Instead, you can use any Google Home speaker or display to act as a remote chime for the Nest Hello. And if the Google Home device is a smart display, you can also see the person at your door.

So your old door bell goes into the bin, and you can hear door bell with Nest Mini.

I have a Nest Mini but not Nest door bell, Nest mini is the typical naughty boy, it does all sorts it is not asked to do, then will not correct error, so "Hay google turn off" instead of turning off music turns off lights. "Hay google turn lights back on" gets I don't know how to do that yet.

Nest mini works great for getting radio 4 or spotify etc. But would not trust it with my heating, and hate to think what it will tell your visitors to do, my grand children thought it was funny to tell it to play music at full volume at 2 am.

I am sure connected to heating they would tell it to turn heating up or down.

[Sandtree]

Thanks Eric

The Nest Hello does support mechanical chimes too (at least a single one) but they universally recommend a 16v transformer. Ours is a 12v and the older style of Square D consumer unit which doesnt take standard modules.

Could put a new transformer in a box next to the CU but that cupboard is cluttered enough and may well update the CU at some point as its full, plastic and a few things are on the “wrong” side of the RCCB.

May get the Nest Hub at some point that’d act as a second chime too but Mrs is for now anti digital assistants in the house (but likes the nest thermostat etc)

[ericmark]

Well the Nest thermostat is not really digital, you turn the dial, and if using opentherm it is also analogue to boiler, should we call it a boiler? I would think it faulty if it boiler the water.

I thought the whole idea of geofencing was daft, but Nest did it automatic and I have not stopped it.

As to consumer unit, now not sure I did the right thing, some debate now on type A and type AC RCD's, being a cheap skate fitted all type AC, and since combined with the MCB as RCBO's I have 14 of them, so at £16 each to change them all is a tad expensive, likely will only change one for front of house sockets, which has the fridge/freezer, freezer, and washing machine on it, all which are inverter drive units.

I could not really use a twin RCD unit as would be impossible to arrange different RCD for lights and sockets in all rooms. And all RCBO means the unit uses 4 less slots, so much smaller. Plus lost at least two freezer loads of food in last house when the RCD tripped.

But for me the Nest door bell is too expensive, and had a remote answering machine in last house, and seen people refuse to answer a disembodied voice.

I have an IP camera so had considered putting it where I can see the door, on my to do list. Last house ended up buying three Lidi door bells so placed around the house, but here rare to get visitors, we are too far from beaten track, so people ring up first to make sure we are in, and even when they arrive, they tend to ring on mobile and say we're here. Postman with parcel tries door, if open he puts in the house.