Emergency Light Test Switch.

I have never known a M.C.B. wear out due to regular switching off and on again. I know a church hall that uses only its Crabtree brown M.C.B.s as functional switches to switch its fluorescent lights on and off as there are no light switches. They have done this two or three times a week for over 50 years and the original M.C.B.s still function well.

What's that phrase financial people like to use - something like 'past performance is no guarantee of future returns' - likewise just because the old fashioned built-like-a-battleship MCBs were good in some respect is no guarantee that today's 'value engineered to a micron of the product standard's minimum requirement' devices will be the same.


I've come across several failed (relatively modern) MCBs - and while I've not been able to tell what the cause of the failure was, I can't help thinking the extra mechanical wear and more arcing could help.


   - Andy.

I have never known a M.C.B. wear out due to regular switching off and on again. I know a church hall that uses only its Crabtree brown M.C.B.s as functional switches to switch its fluorescent lights on and off as there are no light switches. They have done this two or three times a week for over 50 years and the original M.C.B.s still function well.

What's that phrase financial people like to use - something like 'past performance is no guarantee of future returns' - likewise just because the old fashioned built-like-a-battleship MCBs were good in some respect is no guarantee that today's 'value engineered to a micron of the product standard's minimum requirement' devices will be the same.


I've come across several failed (relatively modern) MCBs - and while I've not been able to tell what the cause of the failure was, I can't help thinking the extra mechanical wear and more arcing could help.


   - Andy.