GFCI and Electric Fence Chargers

[Little Bill]

A question was asked if fence chargers can be on a GFCI. They seem to think that because the chargers work when something/someone gets shocked while being grounded, that the GFCI should trip because voltage went to ground. I differed with the questioner for a few reasons.
Thoughts?

 

[augie47]

It may not be the same with all chargers but I had one that was plugged into a GFCI and it never tripped even when I inadvertently "tested" the fence.

 

[hillbilly1]

The chargers are separately derived systems, (isolated output, usually a transformer or electronic) so the gfi will not see any current going to ground.

 

[Little Bill]

The chargers are separately derived systems, (isolated output, usually a transformer or electronic) so the gfi will not see any current going to ground.

That was one of my thoughts as well.

 

[Seven-Delta-FortyOne]

I don’t believe they will. As far as I understand, the AC side charges a transformer, or charges a capacitor, and then sends pulses down the line.

So the “ground” on the fence to deliver the shock has to come back to the DC side, so the GFCI never sees an imbalance.

Although my experience with electric fence chargers is the stand alone solar type, which we had all over the ranch.

 

[Dennis Alwon]

I agree there is no reason the gfci would trip

 

[winnie]

I suspect that for safety reasons most fence chargers are intentionally separately derived systems.

A GFCI can't 'see past' a transformer.

Jonathan

 

[roger]

It's ironic that if located outside a device who's sole purpose is to provide a shock has to be fed from a device that's sole purpose is provide safety in the case of a shock.

 

[drcampbell]

I suspect that for safety reasons most fence chargers are intentionally separately derived systems.
A GFCI can't 'see past' a transformer. ...

Not only that, but they also use the core of the step-up transformer to limit the amount of energy delivered to the fence. Once the core saturates with DC, that's all the zap you're going to get. Likewise when the primary current is turned off and the magnetic field collapses -- the fence energy is limited by what the core can store.

 

[ptonsparky]

Tell the farmer whose cattle have gotten out for the third time that the GFCI is required and see how that goes. Dang thing would work fine then trip on a weekend when I was out of town and the normally available guys, weren't.

 

[hillbilly1]

Tell the farmer whose cattle have gotten out for the third time that the GFCI is required and see how that goes. Dang thing would work fine then trip on a weekend when I was out of town and the normally available guys, weren't.

Usually what would trip the gfi, is a surge from a nearby lightning strike. A lot of them have surge suppression to help protect the charger.