circuit breaker replacement

[nottsrob184]

hello all.
my sons house has a circuit breaker that is duff.
on the side of it it states "type B" and 5A M1 15-45A M2.
it serves his central heating system.
Do i replace it with a 5 amp or the 15A - 45A??
I looked on B&Q website but could not be sure which to get.
thanks

 

[riveralt]

what is the make of the circuit breaker?

or what is the make of the Consumer Unit in which it sits.

 

[nottsrob184]

what is the make of the circuit breaker?

or what is the make of the Consumer Unit in which it sits.

Not sure of the make...i left his house an hour ago.
it fits into a holder that can also house a fuse. thats all i can tell you....sorry

 

[riveralt]

If its an old Wylex rewireable fuse board with an MCB adapter then this would be what you want.
http://www.screwfix.com/prods/48030...ex-MCBs-Incomers/WYLEX-6A-SP-Type-B-Curve-MCB


If it is not a rewireable fuse board then this might be the one.

http://www.tlc-direct.co.uk/Products/WYNB05.html?source=froogle

 

[nottsrob184]

thanks...thats great.
only question i have now is why does it state M1 5A and M2 15-45A?
any idea's.?

 

[riveralt]

Most MCB's of the B type are rated at 6kw breaking capacity.

I think the M1 is rated at 2Kw and the M2 is rated at 3kw.

 

[Taylortwocities]

This sounds like the older type of breaker - BS3871. Probably has push buttons rather than a lever.

The "M" designations relate to the breaking capacity - ie the short-circuit current that the device can handle (Icn)

M1 means that it can handle 1kA

You have a B5 device that will trip at 5amps. B5s are not made any more, you can replace this with a B6 (6amps) , but nothing higher.

 

[ban-all-sheds]

Most MCB's of the B type are rated at 6kw breaking capacity.

26A?

Wouldn't that be an issue with an awful lot of cooker, shower and socket circuits?

I think the M1 is rated at 2Kw and the M2 is rated at 3kw.

8.7 & 13A?

Seems unlikely to me.

 

[ricicle]

What made the mcb 'duff' ?

 

[riveralt]

two pints and big fingers - should be 6000amp

 

[ricicle]

two pints and big fingers - should be 6000amp

Yeah, I thought you meant kA not kW

 

[ban-all-sheds]

two pints

Of what?

Have you been making homebrew with 23% yeast fermented until it dies again?