North American Fruit Explorers mailing list at ibiblio

["Alan Haigh" <alandhaigh@gmail.com>]

If the fence is galvanized without plastic coating and is at least 4' high with an electric strand on the top it can stop squirrels in my experience.  The kind of charger used for pets is best because it creates a constant charge- these are plug in units.  The pulsing units provide an opportunity for a squirrel to pass over between shocks.  Obviously if you have several strands the chance of this happening is reduced.  Works best when conditions are moist.

 

The plug in chargers can be located next to the house and you can run the wire a long ways if you use well insulated exterior wire (the grey stuff)  I put it right on top of the ground letting the grass hide it as it carries much less than a fatal charge for even small humans.  I'm not recommending this and I sure don't know what code is in your town but it worked for me.  Really- never been electrocuted, even a little.

 

Be sure your fence is well grounded by driving a copper stake very deep, say 3 or 4' and wiring it to the fence.