40 41
resistance +fire hydrant ground resistance
If the fire hydrant ground resistance is quite low, computer room ground
resistance clamp resistance value- test line resistance
(2).measurement of computer room and launching tower ground resistance
Generally, computer room and launching tower ground form into two-point
ground system, as shown in the following picture.
3 Application of the building lightning protection ground system
If ground polarities of building are independent, the ground resistance
measurement of each ground polarity shall be referred to the following picture:
If measurement value of clamp meter is lower than the allowable value of ground
resistance, ground resistance of computer room and launching tower shall be
qualified. If measurement value of clamp meter is higher than the allowable value,
please measure it as the single point ground.
Lightning protection
over head line
UT276A/278A OPERATING MANUALUT276A/278A OPERATING MANUAL
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