What must be true before the group enters?
The outer boundary contains the entire group even if the electric line is unavailable.
A competent person records the energizer, grounding and conductor check for this setup.
The log covers all animals, not only the first animal seen approaching the line.
One named reviewer confirms the destination boundary and unresolved exceptions.
Nebraska Extension describes a smaller area with a non-electric perimeter and a short electric section as one way to introduce unfamiliar cattle, while emphasizing frequent checking. USDA NRCS likewise notes that a holding pen may be needed for electric-fence training. Both are planning cues—not dimensions or a release clock.

