I am worried about bears and wolves when camping so I'm looking at portable electric fences.
Are they effective and more importantly just how dangerous are they?
Are you sure this is a good idea at all? If you need an electric fence to keep animals from your camp, then (in my opinion!) you must have done something wrong. As for wolves, did you ever hear of a single case where wolves would attack a camp site? Bears are a different beast, but again: I suggest doing everything to prevent the situation, not to solve it with an electric fence. Don’t sleep where there might be bears. If you do, keep the traditional precautions – don’t keep the food at the campsite, don’t cook at the campsite, try to pick a place away from possible animal paths.
Actually, electric fences with an attached alarm are pretty common when camping in Svalbard (lots and lots of polar bears). Yet, this unfortunately has the sole purpose of buying you some extra time to get your rifle and can only be considered the last of last resorts. Additionally the failure rate seems to be rather high.
In any case I don't think you'll need one in 'standard bear' country, just use common bear caution when setting up your camp and definitely pack your food in a bear canister. And those camping in polar bear country, well....
By the way I totally agree that wolves do not pose any threat at all (as long as you don't bring your pets).
They stop my horses and cows just fine. My chickens, not so much :)
In all seriousness, small critters will just get through, and could be as much of a nuisance as a bear.
Also, I'm not sure I'd want to test an electric fence against a bear. Remember, part of the effectiveness of the fence is the shock that deters - but bears can be pretty persistent when they really want something. Very few creatures tend to tell bears, "No".