Grounding The Switch With A Grounding Conductor Buried In The Earth Ground; Verifying The Connection After Grounding The Switch - H3C FS5100-EI Series Manual

Grounding the switch with a grounding conductor buried in
the earth ground
If the installation site does not have grounding strips, but earth ground is available, hammer a 2.5 m
(8.20 ft) or longer angle iron or steel tube into the earth ground to act as a grounding conductor. Make
sure a minimum of 0.7 m (2.30 ft) is left between the top of the grounding conductor and the ground.
In cold areas, bury the grounding conductor below the frozen soil layer. In areas with thin soil or rocky
gravel, determine the depth for burying the grounding conductor based on the actual condition.
If zinc-coated steel is used, the following dimensions requirements must be met:
•
Angle iron—A minimum of 50 × 50 × 5 mm (1.97 × 1.97 × 0.20 in).
•
Steel tube—A minimum of 3.5 mm (0.14 in) in thickness.
•
Flat steel—A minimum of 40 × 4 mm (1.57 × 0.16 in).
•
Round steel—A minimum of 10 mm (0.39 in).
Weld the yellow-green grounding cable to the angel iron or steel tube and treat the joint for corrosion
protection.
Figure2-22 Grounding the switch by burying the grounding conductor into the earth ground
(1) Grounding screw
(4) Joint

Verifying the connection after grounding the switch

•
If you ground the switch with a grounding strip:
a. Use a multimeter to measure the resistance between the switch grounding terminal and
grounding point, and make sure the resistance is less than 0.1Ω.
b. Use a grounding resistance tester to measure the grounding resistance of the grounding
strip, and make sure the grounding resistance is less than 1Ω.
•
If you ground the switch with a grounding conductor buried in the earth ground:
a. Use a multimeter to measure the resistance between the switch grounding terminal and
grounding point, and make sure the resistance is less than 0.1Ω.
b. Use a grounding resistance tester to measure the grounding resistance of the angle iron in
the ground, and make sure the grounding resistance is less than 10Ω. For locations with
high soil resistivity, sprinkle some resistance reducer to reduce soil resistivity or replace soil
around the grounding strip with soil with lower resistance.
(2) Grounding cable
(5) Grounding conductor
2-23
(3) Earth
(6) Chassis rear panel