ERICO Practical Guide to Electrical Grounding - Manual (Page 16)

Other items that are located on the outside of the building
that should be considered are lighting fixture standards, pull
box covers and rails. Handhole, manhole and pull box
covers, if conductive, should be bonded to the grounding
system using a flexible grounding conductor (Fig. 1-17).
The NEC Section 370-40 (d) requires that a means be
provided in each metal box for the connection of an
equipment grounding conductor. Metal covers for pull
boxes, junction boxes or conduit bodies shall also be
grounded if they are exposed and likely to become
energized. The NEC in Section 410-15 (b) Exception,
permits metal poles, less than 20 feet (6.4 m) in height to be
installed without handholes if the pole is provided with a
hinged base. Both parts of the hinged base are required to
be bonded to ensure the required low impedance
connection. Lighting standards in parking lots and other
areas where the public may contact them should be
grounded (Fig. 1-18). Keep in mind that the earth cannot
serve as the sole equipment grounding conductor. Light
standards which are grounded by the use of a separate
ground rod must also be grounded with an equipment
grounding conductor to ensure that the overcurrent
protective device will operate. Rails or sidings into
hazardous locations such as grain storage facilities,
ammunition dumps, etc., should also be properly bonded
and grounded (Fig. 1-19). Designers and installers must not
forget that distant lightning strikes can travel through the
rails for many miles. In northern climates suitable bonding
jumpers should be applied across slip joints on water pipes
to enable thawing currents to be applied without burning
the joint gasket (Fig. 1-20).
8 Practical Guide to Electrical Grounding
CADWELD Connection
3/16 Bronze Flexible Cable
Connect To Ground
Pull Box Cover Grounding
Fig. 1-17
Bare Copper Conductor
CADWELD
Type GR or GT
To Copperbonded Rod
Finished Grade
CADWELD Type RD To All Vertical Rebars
At Or Near Unstressed End Of Rebars
Copperbonded
Ground Rod
Driven 10 Feet
Light Pole Grounding
Fig. 1-18
—
A
CADWELD Type
ST Connection CADWELD Type
TP Connection
CADWELD Type
ST Connection CADWELD Type
TP Connection
Far Rail Near Rail
Bare Stranded Copper Wire
To Main Ground Grid
Section A
1/16" x 1" x 20 " Copper Bond CADWELD
Connection
Slip Joint Ductile Iron Pipe
600 AMP Bond
Bond P/N: CAA817A16
Welder P/N: CACHA-AEC- "Pipe Size"
W/M: CA32XF19
Water Pipe Bonding
Fig. 1-20
Rail Siding Grounding
Fig. 1-19
Grounding Book 4/14/99 10/5/99 6:01 PM Page 8 (Black plate)