Intermittent Rcd Tripping

[Shane1089]

Hi guys, i attended a property on friday the tenant has stated the rcd is tripping at intervals of 45-60 mins, i separated the ring legs and upon testing i was getting a reading of 0.60Mohms between Line-cpc on one end of the cable with all loads disconnected, i have never come across this fault before and my question relates to the tripping characteristics of the rcd/mcb. is this a problem you guys have come across before and should the mcb be tripping out although i know the rcd is more sensitive? many thanks in advance.

 

[44ALLAN]

So..........what was tripping?

Mcb or Rcd?

Or Rcbo?

Give us a clue mate

Rcd .......earth fault.

Mcb .............short cct/overload/earth fault.

 

[Shane1089]

sorry my bad, still new to this... it was the RCD mate

 

[SPARTYKUS]

600,000 Ohms. Thats alot of Ohms!

did you test the RCD as well. Just to be sure. Seems a bit high for an RCD to trip but who knows whats going on there.

 

[Shane1089]

Thanks for the feedback rcd was operating fine following a ramp test and testing at half 1x and 5x

 

[44ALLAN]

Hi guys, i attended a property on friday the tenant has stated the rcd is tripping at intervals of 45-60 mins,

think.........

45-60 min intervals................mmmmmm

Timeclock/pump with level switch/heating pump..............possibilities are endless but easy really when you think about it

Well...........sometimes lol

 

[Shane1089]

lol but are you saying the the <1Mohm reading between line to cpc has nothing to do with it? even when i attended i forgot to mention(my bad) the rcd got to a point where it was constantly tripping even with all loads plus boiler disconnected sorry if i sound like a complete novice

 

[44ALLAN]

mmmm

If you have an RCD tripping with everything disconnected on the outgoing terminals then..............well..........c'mon?

 

[Outspoken]

Shane, snapped a picture of you going to work chap...

 

[Shane1089]

All jokes aside i understand the fact of mcbs tripping at under <1Mohm my original question was in regards to how the mcb could/should react with the rcd in line with this type of fault, although you may already have had your kicks for the night