by ericmark »
Sat Nov 08, 2008 8:25 pm
Please remember this is a lot of guess work but here goes.
You have connected the switch wire which may be same colour as neutral to the neutral cables and when you switched on the light it caused a short circuit and tripped the MCB.
When you fitted a dimmer switch the direct short circuit has blown the semi-conductor devices and so no longer causes a short circuit so lights continue to work.
So am I anywhere near? The switch wire should be two line coloured cores but most twin and earth has one line colour and one neutral coloured core. So a line coloured sleeve is used over the neutral coloured wire. But it is easy for these to fall off which means one has a line wire with a neutral colour.
Both in projects and on my own web page
http://www.ericpalmer.fsnet.co.uk/Lighting.html there are diagrams as to how lights are wired as standard.
Eric
