12F407 - 336.4 AAC 3-over-3 Double Circuit Double Deadend Underbuild (Obsolete - 12F402)
Revision 3
Aug 12, 2022
Notes:
- 50’ minimum pole height without communication attachments. 60’ minimum pole height with communication attachments.
- Engineer must specify the size & number of down guys and anchors depending on conductor design tension, line angle, available down guy lead and span length. Refer to T&D Guideline 4-6 and Compatible Unit Sections A and G.
- To avoid accidental contact with jumpers, primary down guys must be equipped with 144" fiberglass guy strain insulators (MID 939267). Refer to T&D Guideline 4-6-1.5 for more information on use and placement of guy strain insulators.
- The upper circuit on 3-over-3 double circuit structures is an express feeder. Connect all transformers, risers and 1Ø and 2Ø taps to the lower circuit
- Crossarms to be set to split the angle in the line. Guy should be set in the plane of the crossarm if possible.
- This assembly is intended for primary conductors with a maximum working tension of 2,500 lb/Ø or less. For deadending conductors with a maximum working tension between 2,500 lb/Ø and 4,000 lb/Ø refer to Assembly Unit 12F417.
- New overhead double circuit construction is allowed in rural areas only. Refer to T&D Guideline 4-23-7.0 — Design Practices for Constructing Double Circuit Lines.
| Compatible Unit | Description | Quantity |
|---|---|---|
| I0387 | Insulator, 15kV Sgl Polymer Vise-Top Insulator - 5/8" x 6-1/2" Pin Fiberglass Crossarm Mount | 6 |
| I0315 | Insulator, 15kV DE Porcelain Dbl DE Assembly w/ 20” D.A. Bolt - Two-Way Pole Mount DE | 1 |
| I0321 | Insulator, 15kV Polymer Sgl DE Insulator (Fittings: Clevis-Eye) | 12 |
| T0303 | Clamp, Straight Line Deadend 336.4 kcmil (3/0 - 477 kcmil ACSR, 4/0 - 556 kcmil AAC) | 14 |
| X0212 | Crossarm, 10' Deadend 4-Pos. Hvy. Duty | 2 |
| Z0640 | Connector, Wedge 336.4 - 336.4 kcmil AAC/ACSR | 14 |