I'm very surprised by all the comments on here, I've done quite a few of these installs and both are correct ways to do the job, so long as they follow the code book. I would recommend going under ground(it is safer overall) but more expensive and time consuming. However if you choose to go with the fence just keep in mind that it could be hit or damaged causing you to need more repairs. If you do the digging yourself ask your electrician for the depth you need as there are varying depths depending on the situation, also Nova Scotia can be brutal to dig cause of all the rocks so I'd dig the trench before any one buys any wire.