Page 435 - Moving the Earth_ The Workbook of Excavation
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BLASTING AND TUNNELING
BLASTING AND TUNNELING 9.35
FIGURE 9.28 Series wiring.
Resistance of Electric Blasting Caps in Ohms per Cap
Copper wire Iron wire
Length of Instantaneous Delay Instantaneous Delay
wire, feet caps caps caps caps
4 1.26 1.16 2.10 2.00
6 1.34 1.24 2.59 2.49
8 1.42 1.32 3.09 2.99
10 1.50 1.40 3.59 3.49
12 1.58 1.48 4.09 3.99
14 1.67 1.57 4.58 4.48
16 1.75 1.65 5.08 4.98
20 1.91 1.81 6.08 5.98
24 2.07 1.97
30 2.31 2.21
50 2.42 2.32
60 2.69 2.59
80 2.71 2.61
100 3.11 3.01
150 4.11 4.01
200 5.12 5.02
Resistance of Copper Wire
AWG Gauge No. Ohms per 1,000 feet
6 0.395
8 0.628
10 0.999
12 1.588
14 2.525
16 4.02
18 6.39
20 10.15
22 16.14
FIGURE 9.29 Resistance of caps and wires. (From the 16th Edition of Blasters’ Handbook.)
