ERICO Practical Guide to Electrical Grounding - Manual (Page 65)

57
EQUIPMENT BONDING
Equipment within the facility must be carefully considered
as to its need to be bonded to the facility ground system. Of
course, all electrical equipment must have a grounding
conductor as dictated by the NEC. Additional grounding is
sometimes needed as shown in Figure 3-21. As pointed out
previously, the frequent use of ground plates (Fig. 3-22)
provides accessible grounding points throughout the
building. When removable grounds are required near a
grounded column or beam, a stud can be welded to the
steel and the bonding jumper can be attached using a lug
(Fig. 3-23). Providing mechanical protection to the stud is
recommended.
In cable installations, the tray’s bolted joints do not always
provide the required low resistance. A separate ground
conductor must then be run the length of the tray, bonded to
each tray section and to adjacent steel columns. Or, jumpers
can be used across each joint. The cable can be welded to
the tray if it is steel (Fig. 3-24) or bolted to the tray if it is
aluminum (Fig. 3-25).
Chapter 3: Building Interior Bonding & Grounding
Cable Rack Grounding
Fig. 3-18
Fig. 3-19
1/8 x 3 x 3
Steel, Arc Weld
To Cable Rack Channel
CADWELD VB
CADWELD VN
Alternate -
Specify Right Hand
Or Left Hand
CADWELD Connection
VTC2V Mold
#150 Weld Metal
CADWELD Connection
VTC2V Mold
#150 Weld Metal
CADWELD Connection
PTC2V2V Mold
#250 Weld Metal
Upper Rack
Lower Rack
250 KCMIL Copper
CADWELD
Mold
Ground Plate
Fig. 3-20
Large Motor Grounding Detail
Fig. 3-21
Motor
CADWELD Lug
(2 Hole NEMA)
With Lock Washers
And Bolts
Field To Locate Ground
Plate (2 Hole, CADWELD
CAT. NO. B-162-2Q
Mount Top Flush With
Concrete
CADWELD Type TA
To Ground Loop
4/0 CU GND Cable
Motor
Concrete
Base
Grounding Book 4/14/99 10/5/99 6:01 PM Page 57 (Black plate)