Originally Posted by
cpt.capslock
a little more precisely, it adds noise to your nerve system.
Not only does that control your muscle movements, but there's a lot of other 'communication' running trough them: Your senses (pain, heat, cold, touch/pressure, etc.). Because of the high voltage, the electricity will manage its way trough clothing and skin, but because of the low amperage it will not do any real damage.
However, it does add a lot of noise to the signals running trough your nerves. This renders your body unable to 'deceipher' the real messages coming from your brain. Because of this the target often faces confusion and becomes unbalanced. If the charges (roughly) have the same frequency as a human body, it'll also cause the muscles to do a lot of work in little time - the spasms you'll probably think of first. This literally causes the target to become too tired to move.
Back to the point on how it would affect zombies: Pain, heat and cold don't really matter, but the muscle movements will still do their job. However, that is assuming the frequency of the zombie's electrical signals is roughly the same as a human's. The virus could have mutated this.
Also, the confusion and disturbance of balance might or might not be affected. These three are all determined by the virus, and thus by the writers.
They can go any way they like without being inconsistent or scientifically wrong (as far as these zombies go).