I don't think the word 'only' applies here, 'cause that's more than half of the prisons.
The Electric Fence is the same as [[Fence]] , but is blue and when your are trying to cut it, it will electrocute you. (You will take 20 damage, and be sent to infirmary.)
You can still cut it, if you'll disable [[Generator|The Generator]]. It was
only used in [[Stalag Flucht]], [[San Pancho]], [[Jungle Compound]],[[HMP-Irongate]] and in some prisons of [[The Escapists 2]].
In the Escapists 2, electric fences will sparkle with electricity and shock you too near.