My son bought an old terreaced house recently and changed the old consumer wylex consumer unit to a new one with an RCD the system had one ring main, a cooker circuit and two lighting circuits, he tested the circuit and everything seemed to be okay but when he switch on the unit nothing would work except the lights would only flicker, he put the old one back on and everything worked, any idea what the problem may be - my son has arrange for an electrican to sort it out for him but I am intrigued as to what the problem may be:?:
Hi Dave o,
I would keep quiet about changing it as it's illegal work to DIY a consumer unit change!!!
however for info the most likely thing wrong is in not having the mains 'tails' connected correctly. he will have done the screws up tight on nothing!
If you look at the incoming RCD main switch you will see that unlike the old wylex terminals the new ones are a 'stirrup' type which even when undone fully won't have opened unless you push HARD on the screws, if not the wire goes behind the stirrup instead of inside it. This mistake has caused Lots of fires due to arcing between wire & back of stirrup.
Same set up as with an individual MCB's but they are easier to see.regards