TROF
Electrical Grounding & Supports
Electrical Grounding Chart
Table 1 below provides the Minimum Cross Sectional area for two side rails. Using the Fitting Prefix Number (244), the proper value is determined by the Flange Width (column 1), Load Depth, (column 2), and material (column 3). 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 1
Table 2
Fitting Prefix Number
Min. X-Sect for 2 Rails (NEC Table 392.60(A)
Maximum Ground Fault Amperage (in Amps)
Material
X-Sect Area 0.40 in 2 0.60 in 2 0.70 in 2 1.00 in 2
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
-
100
1000
-
Flange Load Depth
Material
-
200 400
1200
2 - 13⁄16" 4 - 1 1⁄4"
3" 4" 5" 6"
2 - Mill-Galv 0.60
–
0.40
–
3 - HDGAF 4 - Alum.
0.60 0.60 0.40 0.70 0.60 1.00 0.70 0.70 0.60 1.00 0.70 1.00
For Example: If the fitting prefix is 244, 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 in 2 . The Amperage is 1000.
TROF- Electrical Grounding & Supports
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