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Section 2 Installation
In addition to or in place of the water supply
pipe, other grounding electrode systems shall
be used:
• Metal frames of buildings
• Metal electrodes encased in 2″ of concrete
within or near the bottom of a concrete
foundation
• 20′ of 2 AWG bare copper wire buried not
less than 2 1/2′ below the surface
• Underground metal tanks or other such
underground systems or structures
Disconnect switch
Main circuit breaker is
the disconnect switch
Main circuit breaker
Figure 10-20. Within every structure, there must be a
means of disconnecting all conductors from the service
conductors. These disconnects must be clearly marked
and easily accessible. (Wadsworth Electric Mfg. Co., Inc.
and Square D Co.)
Grounding
electrode (rods,
plates, or cable)
Weatherhead
Conduit
Watertight
connector
Red
conductor
Main
service
entrance
panel
Neutral
bus bar
Bond
Grounding
electrode
conductor (GEC)
Grounded conductor
or neutral
Hot (ungrounded)
conductors
Meter pan
Black conductor
Grounding bushing
Bond from grounding
bushing to grounding
bus bar
Grounding
bus bar
Figure 10-21. The service entrance layout must have
continuity of the grounded neutral and grounding elec-
trode through grounding electrode conductor. Metal
conduit must also be bonded to grounding means.