CHINT RCD MAIN SWITCH MALFUNCTION AFTER TEST

[South Spark]

Installed a new radial circuit in a garage from an existing CHINT garage unit.

All functioning well (tests fine) until after the RCD test. Then everything, lights etc stops working.

On investigation, while I've got 244V at the incoming side of the main switch I'm getting a reading of between 85 and 166.5 on the outgoing.

Guessing it's knackered the RCDI'll swap it out tomorrow but wondered if anyone else has encountered this fault. I've never touched CHINT gear.

 

[Deleted member 26818]

Think you missed the point of my comparison..
A 3% failure rate for a life saving device is unacceptable

No not really.
The failure rate of seat belts is offset by the fact that they are tested annually (after the first 3 years), and if they fail the test, they must be fixed or replaced.

Biggest problem with seatbelts is the lap belt type often used for the centre seat in the rear of cars which in the event of an accident can cause severe internal injuries which would not occur with 3 point seatbelts.
Such belts can still be used effectively with many child car seats.

 

[Charlie_]

Sorry, not interested in seatbelts..
Only the 3% failure rate of a life saving device...
There are statutory requirements in place for earthing.. The use of RCDs in many instances are required to satisfy those statutory requirements..
Do you have any statistics for the failure rates of MCBs?

 

[Deleted member 26818]

To start with any safety device can fail.
The failure rate according to a report from Electrical Safety First conducted in 2006, was in fact 7.1% falling to 2.8% with regular use of the test switch.

As far as I am aware, there are no statistics for failure of MCBs.

 

[NDG Elecs]

A little while back, there was a thread about the reliability of RCDs.
Apparently only 3% of RCDs fail.
Currently there are 3 threads about failed RCDs.

I thought the failure rate was higher than that. I vaguely recall reading so in the Beama RCD handbook. Will have to find it again

 

[Bobster]

Think you missed the point of my comparison..
A 3% failure rate for a life saving device is unacceptable

Now you're right, but not completely right.

50% failure rate would be entirely acceptable if you had diagnostics to warn if it had failed. A seat belt for example, might not buckle one day.

Or if these failures failed safe. RCD trips and goes open circuit.

The real numbers you need to look at are the mean time to dangerous failing.

Anyone designing safety circuits or machine design will know all about this.