MIL-HDBK-1025/10
Table 34
Insulating Plastic Guards/Platforms for Electrical Workers
Guard rating for accidental brush contact
Maximum use rating kV
Proof test withstand voltage
(60 Hz)
(in-service testing)
Class
Criteria
Phase-to-ground kV
Duration,
Phase-t1 -
o
Phase-to-
minutes
phase
ground
60 Hz
dc
2
14.6
8.4
13.0
18
1
No flashover other
3
26.4
15.3
24.0
34
1
than momentary as
4
36.6
21.1
32.0
45
1
a result of too close
spacing of electrode
5
48.3
27.0
42.0
60
0.5
6
72.5
41.8
64.0
91
0.25
1
Cover-up materials are tested at values greater than the 60 Hz use maximum phase-to-ground
values. The maximum use phase-to-phase values relate to guarded-phase-to-guarded-phase.
The units are not rated for bare-phase-to-guarded-phase potentials.
Prework Procedures
5.4.3
WARNING
Do not start work until the requirements of Table 35 have been
completed.
Table 35
Prework Procedures
I.
Work Approval. Obtain energized work approval.
II. SOP/JHA preparation.
A. Determine existing condition.
B. Determine the voltage rating of circuits to be worked on, distances to other energized
lines, and location of work.
C. Evaluate the following:
1. If aerial lift equipment can be used.
2. What personnel qualifications are needed for the work.
3. If special equipment, tools, or hazard protection are needed.
III. Before starting work
A. Review work and safety precautions with the crew before work begins (including
tailgate briefing).
B. Inspect tools/equipment before starting work.
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