ERICO Practical Guide to Electrical Grounding - Manual (Page 50)

42 Practical Guide to Electrical Grounding
Fig. 2-48
Very large buildings require more air terminals,
down leads and ground terminals.
Fig. 2-47
More extensive systems are required on larger
buildings and with different soil conditions.
Fig. 2-49
Protected areas can also be determined using the
rolling ball theory.
No Air Terminal; Roof Edge
Covered Under Higher
Air Terminal Protection.
150 Foot
Radius
CADWELD Type VB
Copper
Downlead
Weld
Lightning
Mast (Pipe)
CADWELD Type VV
Copper Downlead
Main Grid
CADWELD Type TA
Fig. 2-51
Steel tower lightning masts may be used in
locations such as electrical substations.
Fig. 2-50
All rooftop equipment must have air terminals unless
they have skins more than 3/16 inch thick. If they
have skins more than 3/16 inch, they must be proper-
ly bonded and will be considered as air terminals.
24" Min.
Grounding Book 4/14/99 10/5/99 6:01 PM Page 42 (Black plate)