c. Ground clamps (Figure 1-11) hold the ground conductor and the grounding rod together
without losing conductivity when exposed to weather and abuse. Ensure that the ground conductor is
opposite to the screw-on clamp. The upper end of the grounding rod must be flush with or below
ground level unless the connection is protected against physical damage.
Figure 1-11. Ground clamps
Check the ground resistance with a megohm meter (Figure 1-12). This check should be made with the
grounding jumper between the water pipe or a good ground and the electrical system. A metallic cold-
water system makes a good point for testing the resistance of an electrical grounding system. If 25 ohms
to ground cannot be achieved, take the following actions:
Figure 1-12. Megohm meter
EN5144
1-6
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