My apprentice found this post on a Facebook group:
Last week we were called to a house to swap a couple of pendants for customers' own lights. Easy peasy, or so we thought. After changing the hall light (aboout 1.5 metres from the CCU in the cloakroom, none of the ground floor lights would work. Checked and found that the neutral in the cable from the CCU to the hall light had somehow disconnected somewhere along its length. Cut it back as far as possible and still no joy. The (chipboard) floor above the light is the tiled bathroom floor and above the CCU is the airing cupboard with the hot water tank, and masses of pipes, so no access from above to replace the cable. The only option was to cut holes in the ceilings, but the customer said that he was having the tank and pipework removed in a couple of weeks which would allow us access, so as a temporary measure (to get them some downstairs lighting) I connected the neutrals in the hall light to the CPCs (16th editon board, so no RCD). Left them working and now just had a text to say that the ground floor lights have stopped working and nothing has tripped. back there tomorrow to see what has happened now. Possibly the live is now disconnected? Never known anything like this before.
Last week we were called to a house to swap a couple of pendants for customers' own lights. Easy peasy, or so we thought. After changing the hall light (aboout 1.5 metres from the CCU in the cloakroom, none of the ground floor lights would work. Checked and found that the neutral in the cable from the CCU to the hall light had somehow disconnected somewhere along its length. Cut it back as far as possible and still no joy. The (chipboard) floor above the light is the tiled bathroom floor and above the CCU is the airing cupboard with the hot water tank, and masses of pipes, so no access from above to replace the cable. The only option was to cut holes in the ceilings, but the customer said that he was having the tank and pipework removed in a couple of weeks which would allow us access, so as a temporary measure (to get them some downstairs lighting) I connected the neutrals in the hall light to the CPCs (16th editon board, so no RCD). Left them working and now just had a text to say that the ground floor lights have stopped working and nothing has tripped. back there tomorrow to see what has happened now. Possibly the live is now disconnected? Never known anything like this before.