How safe are MCBs - worth investing?

your wasting you time, mcb's for a old wylex fusebox will be expensive, you would be a lot safer with a 17 th edition fusebox with either a rcd x2 / mcb mix or rcbo's for extra protection, rcbo's are a lot better, depending on the age of your old system you may be required to bring you earth bonding up to regs at the same time, 16mm to fuseboard and 10mm to water and gas connection within 600mm of first bend, hope this gives you more information, most companies can fit a whole system for around £300

foot
October 2009

Ok thanks all for the advice...

It sounds like I wouldn't be improving the safety of the circuits a great deal by using these which was the main idea.

Do you have any idea what sort of cost I woule be looking at the replace the whole consumer unit with a new one fitted with RCD's? I seemed to think we'd be looking at a few hundred fitted ?!

Timperley novice
October 2009

MCB's will fit into your Wylex box...out with the old fuse and the coloured plastic cap behind, and on with the new. You can't get the lid back on the Wylex though, and the other comments made are very valid.

John
October 2009

MCB's are a more effective protective device than old style fuses. They will have a more consistant overcurrent trip rating (About 1.43). The main advantage is that they are easier to reset, especially on a lighting circuit as trying to replace a fuse/fuse wire in the dark can be difficult. MCB's do not give protection against an earthing fault, so it may be worth considering replacing the existing consumer unit with a new stile containing an RCD.

Tony McD
October 2009

In the UK I believe this change is notifiable to the local council - you would do best to have a certified electrician do it for you - and provide you with a test certificate which you will need if you ever come to sell the property.

A new consumer unit with MCBs should also accommodate an RCD which provides a measure of protection against electric shock on all circuits. MCBs alone provide no extra protection but are less trouble than regular wire fuses.

Peccavi
October 2009