Alternative MCB to M6 Type 1 (MEM)

[topgazza]

I need to replace a M6 Type 1 MCB, 16A, as the current one has gone over sensitive. Are there modern alternatives that replace it or does it mean a whole new, expensive, consumer box ?

 

[ban-all-sheds]

Electrically you can replace it with a B16.

Mechanically you probably cant.

And there's a strong case to say that you must not mix'n'match different MCBs in a consumer unit.

 

[topgazza]

Thanks for replying. I think its the mechanical side that bothers me. I'd assumed the rail fitting was the same and its just the different, improved, ratings on the newer Type B

Interested buy the last comment and its not ideal to mix and match types or even makes MCBs but is it actually verbotten by regulations ? For the sake of one single 16amp MCB the alternative is that very expensive whole consumer unit replacement which on the face of it seems OTT ?

Or I could just replace all the MCBs with Type B...thats if they fit into the MEM consumer Unit?

 

[Iggifer]

Those MCBs are BS3871s so any MCB you can get to fit it will now be 'used', the standard was withdrawn a good few years ago and it's no longer acceptable to install new circuits on these MCBs. I think the only 3871s you'll find now are those plug in Wylex retrofit.

To change one to a BS60898 (modern MCB), you would need to change all of the internal components including main switch/RCD/busbar so really may as well just change the board.

Two options are realistically - pick up a used one on eBay/internet or change the board.

I had one of these die on my earlier in the year, nothing had tripped but I had no lights. MCB was just no longer closed and no number of resets would close it

 

[topgazza]

Mine is displaying signs that it getting a bit "tired". Apart from tripping for no reason it also is very hard to reset again, even with the mains off.

I also thought the realistic...logic .... would be to change the whole board but there are Type 1s on ebay and even Amazon...used "but tested". The house was built in 1986 and I think the MCB consumer unit must have been fitted later

 

[333rocky333]

You can get them new from MEM but likely around 70 pound

 

[topgazza]

I did spot that and elsewhere. Saw a new 32amp for £98 on one website

 

[333rocky333]

You have to preorder via a wholesaler from MEM, every so often they do a production run, I quess thats why there so dear

 

[Iggifer]

You have to preorder via a wholesaler from MEM, every so often they do a production run, I quess thats why there so dear

That and they know full well they've got you by the short and curlies.

Like those MEM RCBO pods for the MEMERA 2 range. Silly money considering how many millions of those MCBs must be installed up and down the country. Those are still being made though (not just old stock) as we had a couple recently and they've changed the packing and I think the ferrule had changed too.

@topgazza any MCB being sold as 'tested' is just a plain lie. Beyond the fact it switches on and off, there's not really any more testing to be done. It might last a week or ten years. If you can get one or two cheap enough then do that for the time being.

 

[ban-all-sheds]

there are Type 1s on ebay and even Amazon...used "but tested".

I'd love to know how the seller(s) "test" MCBs.

 

[topgazza]

Exactly

For £8 I'll take my chances but I'm under no illusions that these are just recycled mcbs

If I thought type B would fit I would replace all of them but not if rails and switch needs replacing as well

 

[bernardgreen]

Mine is displaying signs that it getting a bit "tired".

Is there a reason that it is getting "tired" has it been over worked by lots of incidents of overload making it trip. ?

 

[topgazza]

Not sure Bernard. It's a reasonable assumption for something like that but its a house my sons just bought (I use "mine" as I've been working on the house for a few weeks now doing everything from decoration, flooring, replacing door hinges/latches/handles and lots of other stuff as he is being sent abroad at the moment) but we don't know the history. I did my electrical apprenticeship in the 70s so carry out any replacement work on existing systems such as sockets, light switches, ceiling roses and everything is excellent condition and properly installed from original install. I've not had to do any repairs as such. No sign of any leaks or dodgy fittings such as outside security lights.

Main problem is that when I turn the MCB off it refuses to reset and requires a "firm" action with something heavy to push it on. So it's possibly just a mechanical failure internally in the MCB. I'll see what happens when the replacement arrives.