Every DIY job I do seems to uncover something unpleasant left behind by a previous DIYer or contractor.
Last year I installed a new central heating programmer, which is in a cupboard in a totally separate room from the boiler. At first it kept blowing fuses, until I managed to destroy it totally. After about 3 days head scratching I found the fault was in the boiler junction box where an intermittent live core was connected to earth. This at least explained why one of the original control functions hadn't been connected for the last 17 years, and was easily rectified.
The problem I'm left with though is that the wiring from the programmer to the junction box consists of just two T+E cables, and the live connection to the boiler had been made using one of the bare earth cores. (Never mind though, the previous installer had made it safe by putting green/yellow sleeving on it ! ) I didn't want to get involved in cable replacement, so the best I could do was mark it with red tape and prepare as-installed wiring diagrams.
My worry now is about the legality of the installation. I can't believe it could have been legal back in the 80s, let alone nowadays. I would have been better off left in blissful ignorance even with only a partly functioning control. But since I'm hoping to sell up in another couple of years I'd be grateful for advice on whether I should bite the bullet and get the job rewired professionally.
