Bathroom Wiring disaster

19 Dec 2008
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United Kingdom
I'm helping my brother replace his bathroom. The ceiling rose had the below wiring with all the lives in one slot, the earths together in another and the neutral into a separate slot near the bulb.

He tried to replicate this with a modern ceiling rose and put all the lives in the L slots, the neutral in the N and the earths in the loop ( not the earth )

This melted the wire to the switch as this had a live and neutral through it instead of just the live and neutral becoming a live at the ceiling rose.

I'm guessing the earth did nothing as being in the loop section with no live it wasn't attached to anything.

I have bypassed the switch and wired the rose without it as if its a junction box but the upstairs lights still don't work. He has an old consumer unit and the fuses all look ok. Could any of the other wire in the loop have been damaged. The exposed parts all look fine and completely different to the wire to the switch.

The below picture is the original ceiling rose.


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You have committed the number one most common mistake.
You need to wire it up as shown in the WIKI

On the new rose:
All the reds go into the LOOP
All the earths go into the EARTH
The two blacks that were together on the old rose go to the neutral
The black that was on its own on the old rose goes to the Live

EDIT: You may find that he has fried the switch and you'll need a new one.
This melted the wire to the switch as this had a live and neutral through it instead of just the live and neutral becoming a live at the ceiling rose.

If the wiring has melted as a result of incorrect connections, there is something very wrong with the installation - fuses should blow long before wires melt or even get hot.

You need an electrician. Remove the fuse(s) for the affected circuits and do not use them until the fault is repaired. Continuing to use the circuit is a fire risk.
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Thanks. What fault would cause the fuse not to blow before the wire melted?
The fuse being of too high a value for the wire.

What size fuse or MCB is on that particular circuit?
For lighting circuit it should be 5 or 6 amps, but if he has rewireable fuses, then maybe some numpty has used the wrong fuse wire…….?
Any melted wire/ insulation needs replacing as a matter of urgency
And do you know why the wire melted and the fuses didn't blow? Sounds like something is seriously wrong
Got an electrician coming tomorrow to fix it and give a quote for a new consumer unit. It's impossible to tell which fuses do what and whether they are in the right slot.
Good. Please tell him that you think the light may have been connected to the wrong fuse, as that might save him from a nasty surprise!
A friend had a house previously owned by a BIYer. Pulling the fuse for the sockets put the living room ceiling light off :eek:
Surely even a piece of 30A fuse wire should go pretty damn quick on a dead short live-neutral?

Are we sure it's even a fuse/fuse wire? Or is it a bit of T+E/nail scenario etc.

A colleague found a blown fuse cutout fuse because of a piece of t+e core used instead of fuse wire.

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