Rcbo failure

[Tomington1]

Hi all
I've just had 7 crabtree star breaker type a rcbos fail the half time on 180. I ordered replacements but they are the same tripping around 75ms. Just wondered if any one else was experiencing the same thing, it's only on the 6a rcbos. Making me doubt my tester tbh
Many thanks

 

[SparkyChick]

The tripping current of the MCB part of the device will have no bearing on the RCD test time, or more precisely, should not.

Can you clarify whether the 75ms is for 1x the rated trip current (30mA) or 5x (150mA).

 

[littlespark]

Can you try your tester on another rcbo, to rule it out?

 

[Vortigern]

Can you clarify

He did say Half...

 

[Andy78]

I have had an issue lately with another brand of RCBO.

Testing advice given to me by the manufacturer was to ensure

Batteries were fully charged
Tester recently calibrated
Correct setting on tester selected
Loads removed and circuits disconnected
To try another tester to rule things out.

 

[SparkyChick]

He did say Half...

Yeah, but what does "half time on 180" mean exactly? If it's half I, then the 0 or 180 part is meaningless because the half I test spans multiple cycles. In which case, is it 'they are failing half the time on 180'? In which case, we need to know the test current to establish whether 75ms is in fact a fail or not.

 

[Tomington1]

Can you try your tester on another rcbo, to rule it out?

all of the other rcbos in the board tested out fine just the 6 amps
[automerge]1580839565[/automerge]

I have had an issue lately with another brand of RCBO.

Testing advice given to me by the manufacturer was to ensure

Batteries were fully charged
Tester recently calibrated
Correct setting on tester selected
Loads removed and circuits disconnected
To try another tester to rule things out.

i shall try replacing the batteries. just thrown me out a bit because all the others passed, but i cant imagine there being so many manufacture faults

 

[static zap]

all of the other rcbos in the board tested out fine just the 6 amps

Could that be a feature of attached load ?
Is this a domestic situation ?

 

[Tomington1]

Could that be a feature of attached load ?
Is this a domestic situation ?

hi, i tested some spare rcbos in a spare way on the board, no load and had the same problem
yes domestic dweling these are all brand new rcbos

 

[Sintra]

Try doing a ramp test on the devices and see how many mA causes them to trip. I take it you have your meter set to test type A and not type AC.

 

[Ian1981]

I have had an issue lately with another brand of RCBO.

Testing advice given to me by the manufacturer was to ensure

Batteries were fully charged
Tester recently calibrated
Correct setting on tester selected
Loads removed and circuits disconnected
To try another tester to rule things out.

Awesome advice given there by the manufacturer Andy, bet you could never had thought of them.

 

[Andy78]

Awesome advice given there by the manufacturer Andy, bet you could never had thought of them.

Haha. I did have to inform them I had already tried everything apart from the second tester I didn't have access to.

 

[NDG Elecs]

Yeah, but what does "half time on 180" mean exactly? If it's half I, then the 0 or 180 part is meaningless because the half I test spans multiple cycles. In which case, is it 'they are failing half the time on 180'? In which case, we need to know the test current to establish whether 75ms is in fact a fail or not.

Excuse my ignorance SC.. I am drunk as officially from today I am divorced! Amicably though which is good..!

But half is surely half i.e. 15mA is the test current if the test equipment is doing its thang correctly ...and it should not be tripping whether it be a B6 or a B40... Basically they should not be tripping..I feel I may be missing something as you are always on the ball and knowledgeable...

 

[static zap]

(

I am drunk as officially from today I am divorced! Amicably though which is good..!

)
(Congratulations on a good outcome ... )
Only sure thing about life -as things settle --Change !

 

[SparkyChick]

Excuse my ignorance SC.. I am drunk as officially from today I am divorced! Amicably though which is good..!

But half is surely half i.e. 15mA is the test current if the test equipment is doing its thang correctly ...and it should not be tripping whether it be a B6 or a B40... Basically they should not be tripping..I feel I may be missing something as you are always on the ball and knowledgeable...

You're not missing anything, when I first read it I just felt that a little clarification may help expedite some responses. Clearly I was wrong as most people seem to have interpreted it in the manner in which it was intended (I draw this conclusion as the OP hasn't provided any clarification)

Congrats/Comiserations on the divorce (delete as appropriate)