RCD tripping at 6ma on ramp

[Sq-Pants]

Hello,
I am a diyer doing my own board change shortly (paying a premium for the honour to BC) and have a problem either with my tester or something else. Basically when i test the RCDs and the two RCBOs i have on the board they are tripping on ramp at crazy figures, 6ma on one RCD and 9ma on the other the RCBO's also trip at 6ma, now i bought these a few weeks ago and they were fine then as i tested them but when i was showing my inquisitive son today they were performing like this, on the first RCD i tested it failed on ramp i then tested again and it passed then tested again and it failed and fails every time since. I then tested an RCD spur i have that was fine when tested a month ago and the same happened on ramp. Every RCD i test on x0.5, x1, & x5 is fine it's just ramp.

So is my tester (KT63) knackered or could there be something else affecting the results?

 

[Darkwood]

Welcome to the forum Sq-Pants...

Has your test meter been calibrated?

Regarding the ramp test - why are you doing a ramp test as this does not show you what the rcd trips at it merely shows you how many mA the meter added to the circuit before the device operated, its additional to leakage already on the circuit, this is a diagnostic test normally used with nuisance tripping, if the correct rcbo,rcd trip tests are compliant with the BS7671 then I wouldn't worry too much.

 

[telectrix]

try ramp testing with the outgoing cables dissed from the RCD/RCBO

 

[R G]

When you say you're testing these RCDs I assume the tests are being carried out on the circuits , I suggest you test these RCDs at the outgoing terminals of the RCDs with all circuits disconnected from them , sounds like theres leakage on the circuits that could either be appliance or wiring based ..you could initially try the tests again with all appliances unplugged and other equipment isolated...

 

[Darkwood]

Sq-Pants... Your profile says in training, are you on an Electrical course at the moment?

If so you may be interested in the Trainee section where we have selected mentors and fellow trainee's to help with the expected level of question someone just starting out would ask, its not a requirement to apply and join but it woud be more suited to yourself if you are on a course than asking questions in the main forum

 

[Jay Sparks]

Just out of curiosity, are the RCBO's fed by the RCD?

Cheers

Jay

 

[Octopus]

Popcorn at the ready

 

[R G]

Popcorn at the ready

Op hasn't got any his popcorn machine won't work with the rcd faults

 

[Jay Sparks]

Popcorn at the ready

Have I missed something? I must admit, I didn't read the whole post.lol I just looked at the first few lines about RCD and RCBO's tripping. I need to pay more attention.lol

Jay

 

[Sq-Pants]

Thanks for the quick replies
In reply to the posts

Yep MFT is only 3 months old bought as new with end of line cert
I know a ramp test is not required to demonstrate that the RCD is functioning but i did think that i would be wanting it to trip at not less than 15ma to avoid tripping when in use due to normal earth leakage say from the cooker for example, that was my thinking anyway.
Outgoing cables are disconnected and i am testing on the load side of the device (test probes directly on screws).
RCBOs not fed from RCD, line is direct from main switch via busbar and Neutral is on same block as incoming, Rcd 1 is on block 2 and RCD2 on block 3.
Sorry Darkwood i do need to change my profile i was to start training last year but had to abandon it due to lack of money to see me through an apprenticeship, basically i could not afford to leave my current job.

 

[Octopus]

I never understand people saying they are paying labc. My day rate I'd cheaper than labc so just use a sparky

 

[Jay Sparks]

I never understand people saying they are paying labc. My day rate I'd cheaper than labc so just use a sparky

WOW!! My LBC charge around £145 to test an install! I charge three times that.lol Especially if a DIYer has done the install.lol

Jay

 

[Richo77]

Is your meter set to the 30mA setting?

 

[Midwest]

WOW!! My LBC charge around £145 to test an install! I charge three times that.lol Especially if a DIYer has done the install.lol

Jay

My LBC's charge between £360-500, for DIY install checked by them.

 

[Marvo]

As per what Tel said, I assume you're testing with the outgoing side still connected.