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TN Grounding System 137
Clearing Time Permissible Touch Voltage
t f (s) V TP (V)
0.04 800
0.06 758
0.08 700
0.10 660
0.14 600
0.15 577
0.20 500
0.25 444
0.29 400
0.30 398
0.35 335
0.39 300
0.40 289
0.45 248
0.49 220
0.50 213
0.55 185
0.60 166
0.64 150
0.65 144
0.70 135
0.72 125
0.80 120
0.90 110
0.95 108
1.00 107
1.10 100
3.00 85
5.00 82
7.00 81
10.00 80
>10 75 (asymptotic)
TABLE 7.3 Permissible Touch Voltages as a Function of the
Clearing Time
