Figure 2-10. Measurement of Stray Current Level in Safety Ground Conductor
18.104.22.168.4 Safety Grounding.
Inspect the fault protection subsystem for conformance with the requirements of
MIL-STD-188-124A and the National Electrical Code. Specifically, all equipments supplied with electric power
and other electrical apparatus falling within the jurisdiction of the Standard or the NEC, must be grounded in
accordance with the Standard or the Code. Inspect the facility and the equipment associated with the facility
to see that grounding (green) conductors are present and record the sizes of the conductors. See that all
connections are tight and well made. Record the other information requested about the fault protection
subsystem in Part IV of the Survey Form.
Check to see that color continuity is maintained from the breaker panels to the equipment. In
particular, be alert for white wire/green wire reversals.
Make sure that the neutral white wire (or other designated conductor) is not grounded at
intermediate distribution panels, at switch boxes, or inside equipments. The grounded conductor shall be bonded
to the earth electrode subsystem only at the first service disconnecting means. Facilities which can be
temporarily removed from service should be deenergized and the main power switch locked or otherwise
secured open. With electrical power removed, disconnect the neutral from ground at the first service
disconnecting means and check for continuity between the neutral and the grounding conductor (see Figure 2-9).
A low resistance reading (< 10 ohms) indicates that the neutral is connected to ground somewhere other than at
the first service disconnect, This ground connection must be located and removed. Under normal operation, a
one megohm resistance should easily be attained.