rcbo tripping before ramp test is complete

[matt12321]

hey all

i was wondering what reason would be behind an RCBO tripping out before the ramp test has finished and comping up with trp?

thanks

 

[Octopus]

i have and the reading was appauling between n and e, also all 27 lights have their own joint boxes burried under a garden spanning over 100 meters.

And you are wondering why the RCD tripped. Disconnect the circuit from the RCD and re-test

 

[matt12321]

the circuit is disconnected thats what im saying

 

[trev]

So this immediate tripping on a ramp is after you have disconnected the circuit completely? Also the cables are failing their IR?
You have a couple of problems in this scenario.

 

[Octopus]

Whats your Ze like?

 

[matt12321]

correct. so what would cause the rcbo to trip? earth leakage? induced voltage? earth acting as a neutral somwhere

 

[matt12321]

do u mean zs murdoch. is so 2.8

 

[Hundleton1]

I'd bet condensation has built up in the boxes, never a good idea to bury boxes that contain air

 

[Octopus]

do u mean zs murdoch. is so 2.8

No, I do mean Ze

 

[matt12321]

they dont contain air. there full of magic gel. cant remember ze, but i know it was below 0.8

 

[chrish_1977]

You need to disconnect the load from the rcbo and carry out a ramp test, this will tell you if the rcbo is working correctly or not, did you ir the rcbo, cause some dont like it up em. Then if all is good, it's back to the good ol fashioned testing if the offending circuit, most opd's trip for a reason, not cause they feel like it, has to be something causing it, the more joints there are on a circuit the points of failure too, break the circuit down and go from there

 

[ackbarthestar]

Most circuits installed and buried in the ground should last for a couple of years before they start to cause problems.

Now two years is no time at all. So any connections made outside should have a life expectancy of over 5 years and if done properly should last indefinitely.

I have spent a lot of time changing terminal boxes buried in the ground filled with this 'magic gell' stuff. condensation and water gets in and rusts up the connections. I try not to bury anything in the ground unless its a resin filled torpedo and would certainly not bury any m/c boxes.

Just a query. You have stated that you have 262V on the cable which appears to have been isolated, is this correct?

 

[davethsparky]

Why would you bury metal boxes in the ground? they will rust away in no time at all. Magic gel is useful if used properly in a plastic box, you have to fill the box completely though or else condensation will form.

 

[ackbarthestar]

Magic gel is a pain in the posterior



I tried to change this Tx with a Magic wand, but it didn't work so I chopped it off and installed it all in something like this



So much easier to maintain, don't you think ?

 

[davethsparky]

I did say it has its uses if used properly, clearly wasn't used properly. Nothing is going to work when idiots don't think about what they are doing or know what they are doing.

If it is possible to get the joint above ground it should always be there. Sometimes your stuck with ridiculous lights to fit flush in a patio. Who really needs to light up the sky like that?

 

[telectrix]

I did say it has its uses if used properly, clearly wasn't used properly. Nothing is going to work when idiots don't think about what they are doing or know what they are doing.

If it is possible to get the joint above ground it should always be there. Sometimes your stuck with ridiculous lights to fit flush in a patio. Who really needs to light up the sky like that?

to divert the helicopter carrying the gold bullion, of course.