Wiring Etc - Tado to Worcester 30i

Hoping one of the Guru's out there might help and put my mind at ease.

Background: Recently had a Worcester 30i installed by British Gas, they used a contracted electrician to do the wiring. He also wired in my Honeywell wireless heating controller.

Fast forward to current day and getting rid of Honeywell for Tado. Followed the guides, Installation guide & various video's to check and double check what I was doing.

when I removed the Honeywell receiver I noticed that there was 2 Blue and 2 Brown wires (N & L) twisted together and screwed into the Honeywell. Never thought much about it and did likewise with the Tado receiver, so we have 2 x N & 2 x L.

Onto the Boiler: On dropping the back panel, I see one cable that goes to N & L 230V IN and then the Grey and Black coming out of the same cable, into the relevant locations. There is ONLY 1 cable coming into the back of the boiler and this is it.

Removed the links on the boiler, Moved the N & L over to the OUTPUT Side.

Now as far as I know everything is working as it should, I can control each room (Tado TRV)

But laying in bed and pondering the day, it occurred to me that what I think they have done, instead of running a cable from the fused spur UP to the boiler and installed on the INPUT side, Then another cable from Honeywell to the Input side, they have gone from Fused spur across to the Honeywell and then the one cable similar to what is supplied with Tado, went up to the boiler.

The techie in my tells me to take out all the wiring and start again and do it correctly, but if its working I dont want to cause myself issues, so couple of questions come to mind:

  1. I assume the fused spur SHOULD be supplying the boiler with its AC Power unless there is power coming from elsewhere.
  2. How the heck was it working before, and now??

Not sure what to do for the best so open to suggestions.

Would really appreciate some advice on this.


  • have you split the cables ,and "belled them out " continuity test to check where the cables are going to and from ?

  • Congratulations with the working Tado install! With the cost of copper and materials, this install sounds like a typical contractor using the minimum on a fixed-price job. The boiler/controls should be powered from a mains isolator, fused 3A. You don't mention if there is an Earth wire? If it's working, and there is no safety issue, I'd leave it alone.