RCBO operating times

[silver surfer]

Testing a job yesterday and realised a couple of things, during the RCBO 1n and 5n tests in a lot of cases the 5n value was actually slightly higher than the 1n value,eg 1n=28.2ms 5n=28.7ms (?). Doesnt seem right that multiplying the test current x5 would have a slower tripping time (although still ok)
Also generally if the 1n was say 28.8 then the 5n was 18.6ms
and if the 1n was 18.9ms then the 5n was 8.9ms.
Does this suggest that a difference in approx 0.10 ms difference between 1n and 5n across the board or is this incidental.

Thanks Guys.

 

[alanl]

Did you test it at both 0 and 180 degrees?
That can make a big difference - I've seen 7mS and 28mS on the same RCD.
Alan.

 

[Deleted member 9648]

Mate....lifes to short....it meets the requirements,write it in the box and go for a beer:cool3:

 

[silver surfer]

Did you test it at both 0 and 180 degrees?
That can make a big difference - I've seen 7mS and 28mS on the same RCD.
Alan.

yes both 0 and 180 recorded the highest values.

 

[silver surfer]

Mate....lifes to short....it meets the requirements,write it in the box and go for a beer:cool3:

Like your style......................hic

 

[Geoffsd]

Not an expert but I think it's something to do with RCBOs being operated by electronics rather than magnetism as are RCCBs.

Didn't understand this bit, though. Where did these figures come from?(although I assume you meant to write 10ms.).

Also generally if the 1n was say 28.8 then the 5n was 18.6ms
and if the 1n was 18.9ms then the 5n was 8.9ms.
Does this suggest that a difference in approx 0.10 ms difference between 1n and 5n across the board or is this incidental.

 

[MarkieSparkie]

Testing a job yesterday and realised a couple of things, during the RCBO 1n and 5n tests in a lot of cases the 5n value was actually slightly higher than the 1n value,eg 1n=28.2ms 5n=28.7ms (?). Doesnt seem right that multiplying the test current x5 would have a slower tripping time (although still ok)
Also generally if the 1n was say 28.8 then the 5n was 18.6ms
and if the 1n was 18.9ms then the 5n was 8.9ms.
Does this suggest that a difference in approx 0.10 ms difference between 1n and 5n across the board or is this incidental.

Thanks Guys.

silver surfer, Don't stress over this. A difference of 0.5mS is a greater precision than your tester can accurately measure, the trip time accuracy of BS EN61557 RCD testers is +-10% +1 digit.

 

[silver surfer]

Not an expert but I think it's something to do with RCBOs being operated by electronics rather than magnetism as are RCCBs.

Didn't understand this bit, though. Where did these figures come from?(although I assume you meant to write 10ms.).

yes mate, my mistake,thanks for the reply.