shock!! no trip!

[eganelectrical]

When I wired my ccu I fitted all rcbo's. and tested all trip times etc. all passed!! In the garden mixing cement a few weeks later and water got all around the extension lead near the plugs! I didn't see this because it started getting dark! But Jesus I felt it with a rattle as I unplugged the mixer!
Went in the house and Rcbo for outside sockets still on! Checked trip times the next day and all still fine!! Surely this should have tripped??

 

[eganelectrical]

Extension lead reel was probably plastic, so being wet probably didnt give a good enough path to earth, until you touched it, then you must have got less that 30ma.

would you be so kind to do it again but put a amp clamp round the live and neutral and let us know the leakage

please don't. I'm only joking

Perhaps you can come and do it for me? "Electric Will". Hehe

 

[MDJ]

still haven't confirmed half times on both pole readings if any? and readings of all trip tests, plus my original question, lets have the full details then??

 

[Silly Sausage]

And here's me thinking I can be nasty

Amateur! :smilielol5:

 

[telectrix]

I said it was getting dark so somewhere someone had spilt water near the plugs.

well that's the answer then. a bit of water on the plugs and you will get misfires. mixer will spin erratically and the cement will dry in patches.

 

[eganelectrical]

Mdj its a Wylex 6amp Rcbo yes calibrated..
Fluke multi function
Trip times can't remember but I think along the lines of

X 0.5. No trip
X 1 18ms
X5. 9ms

 

[eganelectrical]

Oh and I also tested with a megger rcd t320

 

[MDJ]

well thats good readings for sure, did you test the ZS out of interest on the ring? I expect an appliance is the factor regarding the tripping, well done for the readings, I was expecting between 20-38 at times 1 and 8-18 at times 5 so looks good regarding the trip, what did you say the earthing method was? not that, that will be the reason why you had the tripping in this case, I just like being nosy.

 

[eganelectrical]

Earthing is a tnc-s. just felt like a big rattle in the hand so thought was over 30mA but as the others said 'can get a nasty one from 10mA' then this must have been below 30mA.

 

[electric will]

And here's me thinking I can be nasty

you've taught me a lot tony

 

[MDJ]

A 30 ma trip should trip at 30% of the rating under fault conditions, this is why 3 computers which leak 2.5 ma are recommended not to be exceeded by 4 on a 30 ma trip, I have no evidence with me about this but have been told this is the case several times, maybe incorrectly haha, assuming there is something in this, just assuming then 10ma will be the danger threshold, actually there was a thread a couple of weeks back regarding the danger level and I think 10 ma was the figure some sparks suggested, if so your lucky you were not killed.

 

[applemac]

get petrol mixer..

 

[decolad69]

A 30 ma trip should trip at 30% of the rating under fault conditions, this is why 3 computers which leak 2.5 ma are recommended not to be exceeded by 4 on a 30 ma trip, I have no evidence with me about this but have been told this is the case several times, maybe incorrectly haha, assuming there is something in this, just assuming then 10ma will be the danger threshold, actually there was a thread a couple of weeks back regarding the danger level and I think 10 ma was the figure some sparks suggested, if so your lucky you were not killed.

RCDs do lull us into a false sense of electrical security ! 10ma is bloody painful, you must have a heart of an ox ! thank your luck stars.

 

[Engineer54]

A 30 ma trip should trip at 30% of the rating under fault conditions, this is why 3 computers which leak 2.5 ma are recommended not to be exceeded by 4 on a 30 ma trip, I have no evidence with me about this but have been told this is the case several times, maybe incorrectly haha, assuming there is something in this, just assuming then 10ma will be the danger threshold, actually there was a thread a couple of weeks back regarding the danger level and I think 10 ma was the figure some sparks suggested, if so your lucky you were not killed.

Can you explain this a little further please??

 

[Knobhead]

you've taught me a lot tony

Going to have to keep an eye on you.

 

[MDJ]

Can you explain this a little further please??

Basically I have been told by an engineer and a rep from a RCBO manufacturer that they don't recommend more than 3 PC s on a trip, their thinking is on average with the monitor a computer can leak 2.5MAs, this has confused me and I have asked why, basically on one Job I have just done we had to install 6 ring mains in one room for 18 computers in Dado trunking, each of the 6 circuits rcbo protected, crazy?? well apparently they recommend 3 max per trip due to nusience tripping. I don't get this myself, your an engineer perhaps you can help me with it. then theres the 10MA situation, a couple of weeks ago there was a good thread about what amount of current actually kills you, I have heard 10MA, but always thought 30 MA, however a fair few sparks here said they had heard it was 10MA, if so and the OPs trip didn't go out when he took a whack I was wondering why it didn't go out, I asked for test results, he gave them, good readings, so, if a trip according to a manufacturer shouldn't have more than 3 computers on it due to nusience tripping and the death value apparently 10MA, and the trip didn't go out then hes kinda lucky? yes?