eden coughed up some electrons that declared:

Thanks for comments so far....

photos posted on flickr

http://www.flickr.com/photos/35218568@N03/

Have had a further dig and the green wire is connected to a metal
spike thing in the earth. Surely the cable will weather if exposed
like this??

http://www.flickr.com/photos/35218568@N03/3504790306/

My gas pipes are like this - no problems that I know of with copper gas
pipes being outside.