Joint Base Lewis-McChord’s distribution system is a single-point-grounded system operating at 13,800 volts.  Joint Base Lewis-McChord has adopted Tacoma Public Utilities (TPU) design criteria as “industry standards” for utility construction.

Services Employed:

• $1.2MM contract
• Hundreds of Housing Units Serviced
• 165- New Guy Poles
• 244-Cross Arms
• 65- Pole Mount Trans
• 608- Insulators
• 66,396′ FT- ACSR Bare Wire Primary
• 37, 742′ FT- TRIPLEX Secondary w/full size ACSR messenger
• 13, 100′ FT- Solid Wire

General Overhead construction requirements:

• All new construction shall be underground unless dictated otherwise by special circumstance.
• Pole-mounted three-phase transformer banks shall be no larger than 3-75KVA.  Pole- mounted single-phase transformers shall be no larger than 100KVA.
• Pole-mounted transformers shall have separate ground for lightning arrestors, case grounds, and neutral conductor.  (Neutral ground is isolated per NESC.)
• Construction shall be Grade B per the National Electrical Safety Code (NESC), ANSI C2.
• Size, sag, and support overhead conductors per NESC and TPU standards.
• Lightning arresters, appropriately sized, shall be provided at all risers, dead-end poles, and at each overhead and pad-mounted transformer. All cross-arms shall be 9 foot in
• length unless application requires longer/larger arms.
• Primary risers shall be constructed using alley-arm construction with arms parallel to main line
• Splices and dead-ends shall be of the automatic type. Deadends shall be polymer-type.
• Stirrups and other connections shall be made using compression type connectors listed for the application.
• Fused disconnects shall be of the loadbreak type.
• Power poles shall be rated Class 2.
• Secondary conductor connections shall be made using compression-type connectors.