C-Channel Swage Ladder Electrical Grounding Chart
Table 1 below provides the Minimum Cross Sectional area for two side rails. Using the Fitting Prefix Number (ex: 247), the proper value is determined by the Flange Width (1st column), Load Depth (2nd column), and Material (3rd column). Locate the line containing the Flange Width (column 1) and follow it to the right to the appropriate Load Depth and Material.
Find that value in Table 2, follow it to the right to the Material column to determine the Maximum Ground Fault Amperage.
Table 2
Table 1
Fitting Prefix Number
Min. X-Sect for 2 Rails (NEC® Table 392.7B)
Maximum Ground Fault Amperage (in Amps)
X-Sect Area
Material
Aluminum
Steel
Aluminum
Steel
13⁄16 Flange X-Sect Area
1 1⁄4 Flange X-Sect Area
13⁄16 Flange X-Sect Area
1 1⁄4 Flange X-Sect Area
.40 sq 2
-
100
Flange Load Depth
Material
.60 sq 2
1000
-
.70 sq 2
-
200
1.00 sq 2
1200
400
2" - 13⁄16" 4" - 1 1⁄4"
3"
6 - Mill Gal
0.60
0.60
0.40
0.70
For Example: If the fitting prefix is 248, the Flange is 13⁄16, the Load Depth is 4, and the Material is Aluminum. The Minimum Cross Sectional Area (X-Sect Area) is 0.60 sq. in. The Amperage is 1000.
4"
7 - HDGAF
0.60
0.60
0.40
0.70
5"
8 - Alum.
0.60
1.00
0.70
0.70
6"
0.60
1.00
0.70
1.00
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