As to why we use consumer units I don't know. Somewhere around 1996 we got consumer units and at the time I was not working in the UK. I think it's something to do with covers over live parts so one can work on them without isolating else where. The HSE is insistence with distribution units they have to be isolated else where which in a house would often result in breaking the DNO seal on the fuse. I have not seen anything which says consumer units can be worked on without isolating else where, but other wise can't see what is the difference between a consumer unit and distribution unit. All I know is where there is not a skilled person in charge then it needs to be a type tested distribution unit. For your safety, only use an existing doorbell transformer within the range specified below or compatible Ring accessories to power your device. CAUTION: If you use the wrong screws to secure the Video Doorbell Wired, you could damage the doorbell during installation, create a fire hazard and be seriously injured. The Ring DIN Rail Transformer (2nd Generation) is designed specifically for Ring devices, and allows you to hardwire compatible Ring Video Doorbells to your mains circuit using existing doorbell wiring, for non-stop power and protection.

If your transformer is in your consumer unit or mounted separately to a wall, make sure to follow this step.

To bypass your existing chime, unscrew the wires from your existing chime. Then twist them together using the provided wire nut. Run the cable down from the outlet to your molding and then choose a path to your Video Doorbell Pro 2

Note: Do not use any screw other than the included long mounting screws when securing your Ring doorbell. Locate the output cables that are connected to your doorbell. These may be connected to the terminals marked ‘output’, ‘8V AC, 12V AC’ or a similar low voltage. Disconnect these cables and put them to one side. Ring Battery Video Doorbell Plus (DIN Rail Transformer required if your existing doorbell system is volt-free at the doorbell, or does not include a step down transformer to lower the voltage to 8 to 24 VAC)If, like most doorbells in Europe, your doorbell only works at 8 or 12 VAC, your existing transformer won't have enough power to support your Ring Video Doorbell Pro 2 and will need to be replaced by the included 24Vdc Ring DIN Rail Transformer. The bypass cable has wire connectors for either end. On each connector, flip up the lever that corresponds to the open wire port.

Ring Video Doorbell Pro (DIN Rail Transformer required if your existing doorbell system only works at 8 to 12 VAC) When it comes to connecting together the components arranged around your chosen DIN rail mounting system, there are various connector options available depending on the exact type of configuration and application you’re working with.You may want to take a photo of your existing chime wiring before you begin, in case you ever want to restore it to normal. If you are replacing a Ring doorbell, align the two small screw holes with two of the existing holes in your wall (fig 2). Loop one doorbell wire around each of the screw terminals on the rear of your Video Doorbell Wired, then tighten the terminals to secure. 12. Screw in your Ring Video Doorbell using hardware in bag A

Note: If you are running the wire up your wall (instead of through it) DO NOT over-tighten the screws. 13. Restore power at the consumer unit Ring your existing doorbell and listen for the chime. If it rings, we know your existing doorbell system is working. When installed, your existing doorbell chime will no longer function, so you will need to use a Ring Chime or Alexa-enabled speaker if you wish to hear a doorbell chime inside your home in addition to the notification on your phone or tablet.To identify this you will need to locate the transformer, which is often installed in or near to your main electrical fuse board. It may be labelled doorbell transformer and needs to be low voltage (8 to 24 VAC) to power your Ring Video Doorbell Wired. Ring your existing doorbell and listen for the chime. If it rings, you'll know your existing doorbell system is working. Follow the sound to find your chime and make a mental note of the location. If the transformer is not rated at 8 to 24 VAC, it is not compatible with Video Doorbell Wired and you should consult a qualified electrician.