This is probably the most humane way to control slugs and barring something unusual it is 100% effective. This video shows how to install and test the electric slug control fence in a raised bed garden.
Slugs will ruin a vegetable garden pretty fast unless some serious means of taking care of them is implemented. The electric fence has proven to be pretty well 100% effective in my experiments to date.
The fence consists of two runs of wires spaced about 3/4 inch apart running around the perimeter of the raised bed – one wire is connected to the +ve terminal and the other to the -ve terminal of a battery.An electric current will flow through the slug if it makes contact with both wires at the same time. The resulting “shock” with usually cause the slug to turn back.
I’ve been using a 9-volt battery as the power source, the battery lasts the whole growing season but the voltage drops to 5 volts or so by the end of the season (my measurements).
It’s a good idea to check the volage once in a while to make sure the battery is still providing enough voltage (corrosion can be a problem at the battery connectors).
A few years ago when setting up a new fence I didn’t have a 9-volt battery connector so I used a multi-battery AA holder that I had on hand. The combined series connection of batteries gave 12 volts. This turned out to be a bad idea as the 12 volts would more often than not kill the slugs rather than just turn them away.