Doorbell transformer

[KennyPowers]

Hi all,

Looking to replace our old school Byron wired doorbell with a video one. Was looking at hard wiring one in like the Eufy one, and maybe even trying to utilise the old Byron chime on the wall.

It looks like the video doorbells need meatier transformers. The transformer already in my consumer unit is a Crabtree one that doesn't look like it meets what would be required. The spec online suggests it needs to be 16-24VAC, 30VA. (I thought these transformers were DC, but guess not)

My question is, if I can find a replacement one in Screwfix etc, would the original wiring (thin bell wire) be able to take the extra power? (6x more power?)

Cheers

 

[opps]

I think bell wire is normally rated at about 1amp. You are looking at 1.25amps.

Personally, I would stick with the bell wire if running new cable is a faff, but I am not an electrician.

 

[ericmark]

6 volt at 5 VA is not quite 1 amp, 24 volt at 30 VA is just over an amp, so very little between them, so cable is likely fine.

Bell wire is ample, but have used LAN cable in past that may be too great a volt drop, if a long run. But no danger.

 

[KennyPowers]

Found on the Eufy website they recommend a specific transformer (Verma off Amazon), that is 24vac 30VA, but unfortunately is 3 DIN wide. I've only got a 2 DIN gap, so could maybe opt for the smaller 24vac 15VA transformer, which may or may not be enough to power the doorbell.

Also wary of putting transformers off Amazon or eBay into house electrics. Wasn't there a rule about not mixing manufacturers in the consumer unit?

 

[opps]

Found on the Eufy website they recommend a specific transformer (Verma off Amazon), that is 24vac 30VA, but unfortunately is 3 DIN wide. I've only got a 2 DIN gap, so could maybe opt for the smaller 24vac 15VA transformer, which may or may not be enough to power the doorbell.

Also wary of putting transformers off Amazon or eBay into house electrics. Wasn't there a rule about not mixing manufacturers in the consumer unit?

The last time that I fitted a Ring. I used an existing single gang socket, fitted a flex with a 3amp fuse and ran it to a separate DIN enclosure.

 

[bernardgreen]

A transformer sold as a "door bell transformer" is NOT designed to supply power continuously,

They are designed to supply power only while someone is pressing the door bell button.

If a door bell transformer is used to supply it's rated current continuously it may overheat and fail.


Rated voltage (AC) 4 V, 8 V, 12 V
Rated current (AC) 3 A, 2 A, 2 A
Rated power max. 36 VA
Rated frequency 50 Hz
PTC primary side
Strain relief clamp top and bottom
Connection C1 Maximum
number of conductors per terminal 2
Cross section solid 1-wire: 1.5 mm² ... 4 mm²; 2-wire: 1.5 mm² ... 2.5 mm²
General data
Duty cycle short-time duty (Duty cycle ≤ 1 min bei Nennlast, 5 min at max. 20 % of nominal load)
Operating position any
Housing type Distributor housing, wall-mounted housing
Mounting type Mounting rail (35 mm), Wall mounting

Nennlast is rated load

https://www.doepke.co.uk/assets/pdfs/Control/Technical-Data-07--RK-24--0520v1--en.pdf

 

[JohnD]

Bell wire is pretty horrible stuff. Mine was wired when the house was built, it looks like 1.5mm T&E

I think I have only seen Bell wire in old houses, and usually shoddy installs. Sometimes also used for extension speakers from the days before portable radios.

P.s.
If you have one inside the CU, it must be insulated and cabled to mains standards. Mine is in a small enclosure next to the CU.

 

[KennyPowers]

I'll check tomorrow, but I think the house has T&E or similar running from the consumer unit transformer through the walls, to the front door into the back of a mechanical chime.

There is then thin bell wire running from the mechanical chime to the door push outside.

Perhaps one way around could be to get rid of mechanical chime and bell wire, fit a socket where the chime used to be, use a plug in transformer that I think comes with the Eufy, and run the cable outside to the video doorbell.

Not sure how I would take out the old doorbell transformer, and have it just chuck 240v out instead tho

 

[flameport]

It looks like the video doorbells need meatier transformers.

They need different power supplies.
You use the one provided by the manufacturer of the new device.
Using existing or other things may or may not work.

 

[morqthana]

A transformer sold as a "door bell transformer" is NOT designed to supply power continuously,

They are designed to supply power only while someone is pressing the door bell button.

If a door bell transformer is used to supply it's rated current continuously it may overheat and fail.

What do your pea bulbs draw?

 

[bernardgreen]

What do your pea bulbs draw?

80 mA from a 12 Volts DC supply separate from the push button circuit