FERC Account 356: Overhead Conductors and Devices (Transmission)

FERC Account 356 records the cost of overhead conductors, insulators, and line devices installed on electric transmission lines.

Definition

Record in this account the cost of overhead conductors, insulators, and devices installed on electric transmission lines.

Account 356 captures the cost of the wire, cable, insulators, and associated devices that make up the electrical portion of overhead transmission lines — distinct from the towers and poles that support them. This includes all conductors from the transmission substation structure to the point where the line terminates at another substation.

What is typically included

• Aluminum, ACSR, or other conductor wire installed on transmission lines
• Insulators (suspension, strain, and dead-end) on transmission structures
• Overhead ground wires and shield wires for lightning protection
• Splices, connectors, and conductor hardware
• Vibration dampers, spacers, and other line devices on transmission conductors

What is generally not included

• Towers and poles supporting the conductors (Accounts 354 and 355)
• Underground transmission conductors and cables (Account 358)
• Distribution line conductors (Account 356 does not apply to distribution)
• Substation bus work and connections within the substation fence (Account 353)
• Conductor replacements treated as maintenance expense

Why this account matters

• Separates conductor investment from structure investment for depreciation and retirement tracking
• Supports mass property retirement accounting for conductor units
• Required for FERC Form 1 transmission plant-in-service detail
• Enables proper cost-of-service allocation for overhead transmission facilities
• Provides data for transmission planning and asset management studies