Hazardous fences
Squint your eyes and look at the picture below to get an idea of a horse's visual perception.
You will see only the two electric tapes, not the four strands of the barbed wire fence. Horses can't see small fencing material as well as they can see 40mm tape, making it more likely that a horse will sustain injury.
A common injury is cuts around the lower leg from pawing, but far more serious injuries also occur. Some will heal, some will cripple, and some will kill the horse.
This barbed wire fence has been made far safer by the addition of two strands of StockGuard 30mm tape, increasing visibility and thus keeping the horses away from the fence. Jagged barbed wire causes perhaps the worst injuries to horses, and as barbed wire is often rusty, infection is another hazard.

Result :
same high tensile action + tape visibilty
Many people remove old fencing and simply use existing posts to attach 2 or 3 strands of StockGuard tape with the StockGuard insulator (F8) which adapts itself to a variety of fence post types.
There are fence situations where it would be more appropriate to provide a safe margin for the horse along the fence by installing the tape a small distance away from the existing fence.



The result is in the photo.

Solid fences offer a surface for a horse to rub against it. Depending on the fence this may not cause excessive problems. However it can constitute a potentially dangerous obstacle should the horse kick against it possibly resulting in broken leg bones.
Vinyl fences look nice when new and are safe. However, horses do use it to rub against them. An adult horse can exert about 240 kilograms of lateral pressure and this can break plastic fencing. Ideally vinyl should be protected with one or two strands of electric tape.