Yeah, james.Wilson I did mean shorted out, joined together at one end. So if that's too high I guess it's a new cable. I should have got the outdoor cable in the first place, the building the Rio is in was an 'on the day' addition to the original spec, so I used what I had on the van. Oh well, live and learn. Thanks for your time everyone. 

its way way too high

The RIO should be on BELDEN (Shielded) cable not 6 core.

Doesn't have to be Belden 

Hi Everyone,

 

Just an update to this issue in case anyone is interested.

 

After the suggestion that it might be water ingress into the cable, I decided to monitor the situation with this in mind. We had a period of about three weeks with very little rain(no really, we did!) and during that time there were no faults. Then, last Wednesday, we had some pretty heavy rainfall all day and sure enough, that night the alarm triggered three times. 

 

I went in on the Friday and replaced the cable with an external grade one and so far, despite plenty of rain there have been no more false alarms. I'll monitor it for a while longer and report back either way but in the meantime, thanks for all your input it was much appreciated.