MEM Fuse Box

[ban-all-sheds]

I have an old MEM fuse box in my house, that I know to be about 26 years old.

Time to get the whole installation inspected.

Could I ask the question of why?

After 26 years all sorts of changes could have been made, damage done, flakiness introduced. The main or supplementary bonding could be lacking or inadequate. The whole installation could be even older, and the lighting circuit could have no earth.

There are all sorts of could-bes, and the recommended maximum interval between periodic inspections is 10 years.

And the fuseboard should be replaced. There's no requirement to bring it up to date, but it will be lacking RCD protection. Your rewirable fuses don't provide such good protection as MCBs, to the extent that cables have to be derated, i.e. for any given size it's not allowed to carry as much current as it would if it were on an MCB. For example, one of your 30A rewirables will allow 54A to pass indefinitely, and will allow 60A to pass for over an hour.

 

[Paul_C]

Your rewirable fuses don't provide such good protection as MCBs, to the extent that cables have to be derated, i.e. for any given size it's not allowed to carry as much current as it would if it were on an MCB. For example, one of your 30A rewirables will allow 54A to pass indefinitely, and will allow 60A to pass for over an hour.

But it's already been established that the board uses BS1361 cartridge fuses, not rewireable types.

 

[ChrisJ78]

He was referring to mine, Paul, not the OP.

 

[Paul_C]

He was referring to mine, Paul, not the OP.

Oops! So he was. My mistake.