Nest Hello UK Install With Integrated Transformer

Anyone finding this post knows that installing a Nest hello doorbell in the UK is far more complex than it should be, so I decided to post my set up.

Inspired by numerous others who had either hacked a mains powered transformer or used a separate transformer housing. Note I'm not a professional, just a DIYer who likes to give things a go!

I'd seen a comment in Madargy's post (referenced below) that the transformer in question wasn't designed to be always on. So I thought I'd come up with my own hack.

My main objective was I wanted one integrated box. Had seen numerous install vids and guides online, and all had a seperate transformer, I didn't like the look of that.

Supplies

The doorbell itself : https://store.google.com/gb/product/nest_hello_doorbell

12v Bell Transformer : https://www.screwfix.com/p/british-general-8-24v-8-va-bell-transformer-module/8707P

Byron 776 Chime : https://www.diy.com/departments/byron-door-chime/1125628_BQ.prd

Project Box (200 x 120 x 55mm): https://www.ebay.co.uk/itm/IP65-66-Waterproof-ABS-Outdoor-Indoor-Industrial-Adaptable-Junction-Box-7Sizes-d/113874850965

Cabling (spares I had lying around)

Drill & Multi tool

Credits (without the below guides I wouldn't have known where to start!):

Madargy : https://www.instructables.com/id/Making-a-Door-Bell-Chime-With-Integrated-Transform/
Paul Lee : http://www.paul-lee.co.uk/how-to/nest-hello-doorbell-wiring-with-deta-c3500-c3501-chime-uk/
Momin Nz : https://youtu.be/oHf-jj3q6CQ

Step 1: Prepped the Project Box

I took my multi tool and drill to the project box and chime.

Drilled holes in the sides of the project box to allow the chime to sound through. And drilled holes in the back where I would drill the box onto the wall. Those holes were aligned with existing holes in the chime. I.e. I planned to screw through the chime, via the project box, onto the wall.

Step 2: Prepped the Chime

Discarded the chime cover, removed the transformer that was in built in the chime and proceeded to cut away a large part of the base, enough to slot the transformer in. This step was crucial so it'd all fit snuggly in the project box. I took my time and cut out a snug fit, including trimming some from the top corners so it fit snuggly into the project box.

Step 3: Wiring

Turned off the trip switch related to my chime from the circuit box.

Wired the mains power into the transformer and then the transformer and bell cable to the nest adaptor and chime. Followed the attached wiring diagram.

Step 4: Wired Up the Nest

Removed the old doorbell and screwed the wires onto the Nest Hello.

Turned on the mains and Tested the whole system and set up the Nest. Switched off the power again and then proceeded to finalise the fittings, screwing the Nest and the project box onto the wall.