Electric fences and accidental death

1

Photograph incident site from a number of angles, including fence details, ground condition and any secondary hazards

2

Location (mark site map or sketch, photos, GPS reference)

3

Estimate the total length/s (m) and record type/s (e.g. number and size of wires in parallel in each section) of electric fence between energizer and incident site.

4

Note any possible causes of entrapment (sketch, photograph), and any secondary hazards.

5

Record the position and type of each wire/post /insulator at site.

6

Test the tension and movement possible for each wire.

7

Check for evidence of contact (burning/arcing, bending/breakage etc.) on the wires.

8

Check for broken/dislodged (even recently replaced) insulators

9

Record the visible ground conditions (dry/wet/muddy/flooded); note if the conditions are likely to be different from the time of the incident.

10

Clip one end of a 1.5 m × 1 mm2 (18AWG) PVC insulated lead to a (relevant, if known) live fence wire and the other to the centre of the 300 × 300 mm square cut galvanized or stainless steel plate, laid flat on the ground where the person was in contact. If the fence has one or more earth return wires, connect the centre of the plate to the relevant earth return wire as well. Capture then download the current pulse waveform in the lead connected to the live fence wire, using current clamp and oscilloscope. Record the peak current. Repeat the test for each live fence wire that was possibly involved.

Peak current =_____A (top wire)

Peak current = _____A (2nd wire down)

Peak current = _____A (3rd wire down)

Peak current = _____A (4th wire down)

Peak current = _____A (5th wire down)

Peak current = _____A (6th wire down)

Peak current = _____A (7th wire down)

Peak current = _____A (8th wire down)

Peak current = _____A (9th wire down)

11

Disconnect the insulated lead between live fence wire and steel plate. Capture then download voltage waveforms using high voltage attenuator and oscilloscope, across loads of 1000, 500, 400, 300, 200, 150, 100, 50 Ω connected between centre of steel plate and the live fence wire that gave highest peak current above. Record peak voltage and any on-site calculated pulse energy (noting instrument used for latter).

Load (ohms)Peak voltage (kilovolts)

No load_______

1000_______

500_______

400_______

300_______

200_______

150_______

100_______

50_______

12

Clip one end of the 1.5 m × 1 mm2 (18AWG) PVC insulated lead to a (relevant, if known) live fence wire and the other to the end of a 1000 mm × 16 mm dia. Galvanized or stainless steel rod, driven 600 mm into the ground where the person was in contact. If the fence has one or more earth return wires, connect the end of the rod to the relevant earth return wire as well. Capture then download the current pulse waveform in the lead connected to the live fence wire, using current clamp and oscilloscope. Record the peak current. Repeat the test for each live fence wire that was possibly involved.

Peak current = _____ A (top wire)

Peak current = _____ A (2nd wire down)

Peak current = _____ A (3rd wire down)

Peak current = _____ A (4th wire down)

Peak current = _____ A (5th wire down)

Peak current = _____ A (6th wire down)

Peak current = _____ A (7th wire down)

Peak current = _____ A (8th wire down)

Peak current = _____ A (9th wire down)

13

Disconnect the insulated lead between live fence wire and steel rod. Capture then download voltage waveforms using high voltage attenuator and oscilloscope, across loads of 1000, 500, 400, 300, 200, 150, 100, 50 Ω connected between end of steel rod and the live fence wire that gave highest peak current above. Record peak voltage and any on-site calculated pulse energy (noting instrument used for latter).

LoadPeak voltagePulse energy

(ohms)(kilovolts)(joules)

No load

1000

500

400

300

200

150

100

50