ERICO Practical Guide to Electrical Grounding - Manual (Page 125)

Practical Guide to Electrical Grounding 118
Outbuilding
Outbuilding
Xformer
Underground Service
Underground Service
Meter
Meter
Meter
A B C
Service
Entrance
Service
Entrance
Service
Entrance
¥ Equipment or outlets and long
branch circuits
¥ All outlets at more than 10m (30 feet)
from Category B
¥ All outlets at more than 20m (60 feet)
from Category C ¥ Feeders and short branch circuits
¥ Distribution panel devices
¥ Bus and feeder industrial plants
¥ Heavy appliance outlets with "short"
connection to service entrance
¥ Lightning systems in large buildings ¥ Outside and service entrance
¥ Service drop from pole to building
¥ Run between meter and panel
¥ Overhead line to detached building
¥ Underground line to well pump
Demarcation between Location Categories B and C is arbitrarily taken to be at the meter or at the main disconnect
(ANSI/NFPA 70-1990, Article 230-70) for low voltage service, or at the secondary of the service transformer if the service is
provided to the user at a higher voltage.
Location Categories For SPD’s
Fig. 7-1
Grounding Book 4/14/99 10/5/99 6:02 PM Page 118 (Black plate)