MK circuit breakers(mcb's)

diamond_dave

Help! I need to get hold of an MK LN5940s TYPE 2 40 amp mcb(circuit breaker) They stopped making these some time ago and the new one dont fit.I dont want to change the whole board for 1 mcb. It must be a TYPE 2 mcb, but NOT the old Siemens ones.Mine are designated M6 and the switch/toggle sits on a flat front face - not inset as in the Siemens.I have tried fleabay, but no joy yet.
I bet my wife that someone will have some of these available, so I just hope that someone can help!!
I was told that the Hager ones will fit with some modification can anyone confirm this also. Cheers all!!

mkaibear

Any of these do you?

http://shop.ebay.co.uk/i.html?_nkw=LN5940s&_sacat=0&_odkw=LN5940&_osacat=0&bkBtn=&_trksid=p3286.m270.l1313

diamond_dave

Thanks for that mkaibear but again they are ALL type B's and I need Type 2's. Keep looking!

andrew-b

Type 2 MCBs complied with BS3871 which was withdrawn in 1994 so they shouldn't be being supplied anymore - though obviously alot still exist (including in my own CU). See http://www.tlc-direct.co.uk/Book/3.6.4.htm. Should be using Types B/C/D now. I think Type B is the next best match. Though if your not sure i would get advice from an electrician (which i'm not). http://www.tlc-direct.co.uk/Products/MK5940S.html ..18mm wide ..is that likely to fit?

What's it for...if it's a circuit for say a shower if necessary you could get a seperate shower consumer unit installed alongside to save you replacing the main consumer unit?

diamond_dave

Thanks for reply andrew-b. The CU was fitted inearly '90s and the only reason I need to change it is because I want to replace a 7.5kw shower with a 8.5kw and the existing breaker is 32amp. The type B mcb's wont fit these CU's so unless I can get a 40 amp my only option is to do what you say or merely install a new 7.5kw shower - which would be the simplest option.

andrew-b

Done some digging for you. There's actually a retrofit kit that allows you to fit newer style MCBs to old MK boxes. I think this is the kit:
http://cgi.ebay.co.uk/MK-retrofit-kit-Sentry-MCB-Wylex-etc-Very-Rare-/110539554530 ...not sure how you use it though or whether it meets current regs etc though. I came across a 5-year old post on screwfix forum by baldelectrician (who also posts here) but his link to the MK site is now broken. If it can be used safely it seems to fit the bill.

andrew-b

It's MK part number 5567s

diamond_dave

Hi andrew-B yep, I saw this myself but it looked like it might be a big job as fitting the retro kit means fitting ALL new mcbs!! I think that if I cant get one I'll just stick to a 7.5kw shower. But PLEASE keep on looking. Any sparks out there with an old one would be great.

baldelectrician

MK have withdrawn the retrofit kit (they promosed they would not stop selling the retrofit kit, but withdrew them last year - to do with the Honeywell takeover me thinks)

They can not be obtained now, but look for the retrofit kit on ebay

From your post I can see you are unsure what you need to do. I would suggest contacting an established firm as they will be able to source one of these.

My local wholesaler operates a 'graveyard' where the regular clients hand in excess mcb's. They do not have old style MK available in 40A

diamond_dave

Many thanks baldelectrician. Please keep checking.

baldelectrician

I was going to suggest 'the fuse company' but they do not have any.

They are pretty dear (the going rate was £45 for ONE before they sold out- according to my wholesaler)

They are like hens teeth