Yes, but you don't want to ground it directly, that won't work. You can run the loop wire through a lightning arrestor (one that is designed for telephone wiring would probably work) that is grounded (preferably by a short straight wire to your ground rod). Essentially there's a gas tube in these that only conducts when there is lightning strength voltages.

Back that up with a MOV on the terminals of the invisible fence unit (you can buy these at Radio Snack and other places) and a decent surge protector on the power side.

MOVs can have excessive capacitance. Better is to use devices that also earth phone lines. GDT are one example. However the semiconductor devices used by the telco and others is a better low capacitance connection so as to not weaken invisible fence signals.

More critical than a protector is the connection to earth ground. It must be low impedance. That means not inside metallic conduit and typically less than 10 feet. The invisible fence must exit the house adjacent to what actually does the protection - single point earth ground.

Now, why do you know the surge did not enter on AC mains? A lightning strike very far down the street could have been incoming to all household appliances. Which ones get damaged? The ones that make a best outgoing connection to earth. Invisible fence and appliances sitting on a concrete slab would be ideal victims.

Also ideal victims are TVs. Incoming on AC mains. Outgoing (maybe via HDMI ports) to earth via a properly surge protected (earth) TV cable. Damage is often on the outgoing path.

If any wire in any cable enters without first connecting to single point ground, then a surge will enter the building. Then hunt for destructive paths to earth via appliances. Did you have a 'whole house' protector on AC mains? If not, then only minimal protection existed.

Thanks for the replies. Guess this is more complicated than I realized. I just assumed the invisible fence was the culprit because it was connected to a surge protector that was destroyed. Also the breaker for that outlet was tripped.

Please forgive my ignorance.... When you say whole house protector.... Are you referring to something at the breaker box, a lightning rod, or something else?

Something at the breaker box. I have one of these on my house.

Here is a link that might be useful: Leviton Panel Protection

A whole house protector will help, but it's still good to protect all incoming connections from the outside.

> ... but it's still good to protect all incoming connections from the outside.

That is what a 'whole house' protector does. Best protection for cable TV is a hardwire from cable to single point earth ground. A low impedance (ie 'less than 10 foot') connection. Invisible fence cannot be earthed directly. Make the low impedance connectxion to earth via a protector. An example of protection of outside connections.

No protector does protection. Effective protectors connect to what does the protection - single point earth ground. Protector on the invisible fence did nothing if the low impedance connection did not exist.

Do not confuse safety ground in a wall receptacle with earth ground. Those grounds are electrically different.

It is not diffcult or complex. Concepts are new even though this science has been well understood and proven for over 100 years. Effective protectors only do what a wire would do better; make a connection to single point earth ground. Only then is each incoming wire protected.

This post was edited by westom on Fri, Jul 25, 14 at 8:55