UFC 3 -520-01
June 10, 2002
Alarm and detection systems.
Exit and emergency lighting.
Security and surveillance systems.
Lighting and power required to conduct essential operations.
Specific facilities can have additional alternate source needs for other
communications equipment, essential refrigeration, and other mission essential
Refer to Chapter 13 for specific design criteria for alternate source systems.
Locate service entrance equipment in readily accessible spaces to facilitate
disconnection of power in case of emergency. Coordinate the service entrance location
with the exterior distribution system to ensure that service and feeder circuit lengths are
as short as practical.
Service conductors 600 volts and less should be installed underground from
transformers, regardless of whether the transformers are on poles or at grade. Aerial
services can be provided for buildings having a service ampacity of 200 amperes or less
that are located in areas of installation where appearance is of no concern, such as
industrial or warehousing areas, and where safe vertical clearances can be maintained.
Calculate the ampacity of services in accordance with paragraphs 6-2 and 6 -3.
Services greater than 600 volts to structures should be installed underground.
Provide incoming services tapped from aerial distribution circuits with surge protectors
at the service entrance equipment (refer to Chapter 11 for surge protector design
criteria). Limit services exceeding 600 volts to the following types of facilities:
Large facilities requiring a variety of load centers.
Facilities having a connected load of 2,000 kVA or larger.
Facilities where low voltage services are impractical due to cost or technical