Crabtree C50

[now260]

Hello

Can you help me please?

I need to replace this switch with one I have spare.
Mine has this info on it:

250/440V.50~AC
BS3871
415 3ph
Cat M3

Can this ine be used:

Cat M4.5 BS3871
240v 1ph
240/415v 3ph
ref cal temp 40 20


They are both 5amp.

Thanks alot.

 

[Adam_151]

IIRC,

The original C50 breakers (with white writing) were type 2 and M3 breaking capacity

While the newer ones with yellow writing were type 3/C and M4.5 breaking capacity.

[why they suddenly started making them all type 3 instead of type 2 I don't know]


So it sounds like you are wanting to change a type 2 to a type 3, in which case you'll have to confirm the earth loop is in spec

 

[ricicle]

Why do you need to change it ?

 

[now260]

Hello
Thanks for the info.

I need to change it as some of the lights will not come on. All the MCB switches were in the ON position. The one I am changing didn't turn any lights off or on so I am hoping that this is the probelm.

 

[ricicle]

There could possibly be a fault on the circuit which has caused the operation of the MCB in the first place (and it's demise). If that is the case changing it will not solve the problem. The circuit really needs checking first !

 

[now260]

OK I will get someone to check it.
Thanks for the feedback.

 

[333rocky333]

Wf still sell them new

 

[JohnD]

I still have some in the loft.

C50 is not an MCB. The "M" stands for miniature.

 

[kai]

From what the OP specified, it appears that the C50 breaker had a maximum safe fault breaking capacity of 3kA.
The fault was probably greater than 3kA, hence the safety mechanism inside the breaker shut itself down permanently, indicating to the user that it needs replacing, having interrupted a higher current fault.

 

[ban-all-sheds]

http://www.theiet.org/forums/forum/messageview.cfm?catid=205&threadid=43666&enterthread=y