Drag to turn the pole, right-drag to pan, scroll to zoom. Click any part to see what it is.
How a 12 kV distribution pole is put together
A distribution pole carries the 12.47 kV primary at the top, the transformer that steps it down to 120/240 V, the secondary and service drops below that, and often telephone, cable TV and fiber lower still. Every piece has a place set by clearance rules, and every piece adds load that the pole, its guys and its anchors must carry when the wind blows.
Use the Model tab to build a pole: pick a common configuration, then change the circuit, framing, equipment and spans. Click any part for what it is and which standards cover it. The Wind loading tab shows the GO 95 calculation step by step, and this page explains the parts and the rules.
- Framing follows Anaheim Public Utilities (APUD) construction standards and the GSA3 and GSA11 pole designs, with LADWP, SCE and PG&E practice noted where it differs.
- The loading method matches O-Calc with a fixed base and linear analysis, and was checked against Anaheim O-Calc runs.
- Equipment sizes and weights are typical values. Use the owner's standards and manufacturer data for design.
Parts of the pole
Each entry opens the part on the model. If the current pole does not have it, a configuration that does is loaded.
How wind loading works under GO 95
The pole is checked as a vertical cantilever fixed in the ground. Wind pushes on everything attached to it and on the pole itself; unbalanced wire tension pulls it sideways; and heavy equipment hung off to one side bends it too. The bending moment is largest at the ground line unless guys carry part of the load.
- Wind and ice (Rule 43). Light loading, at or below 3,000 ft elevation: 8 psf on cylindrical surfaces and 13 psf on flat surfaces, no ice, 25 °F. Heavy loading adds 1/2 in of ice at 6 and 10 psf.
- Wire tension acts along each span. Where spans balance, as on a tangent pole, tension cancels; at angles, dead-ends and taps it does not, and a guy is placed against the resultant.
- Stress at each height = bending moment / section modulus + vertical load / area. A wood pole's section modulus grows with the cube of its circumference, so a slightly thicker class gains a lot of strength.
- Safety factor (Rule 44, Table 4). New wood poles need 4 in Grade A and 3 in Grade B. Existing poles may stay until the factor drops to 2/3 of that (Rule 44.3), so their allowable stress is higher.
- Utilization is the stress divided by the allowable stress. APUD designs new poles to 95 % and older poles to 90 % or 80 % (Design Manual DM 8). An existing pole more than 15 years old needs intrusive test results before its strength is relied on (Rule 44.2).
| Item | GO 95 requirement |
|---|---|
| Grade A | Class H supply (5 kV up to 300 kV between conductors, so 12.47 kV) over communication circuits, on joint poles or at crossings, and at crossings over major railways (Rule 42, Table 3) |
| Grade B | Class H supply in all other cases; Grade C is not allowed for 12 kV supply |
| Wood pole safety factor | A: 4, B: 3, C: 2 at installation |
| Replace or reinforce at | 2/3 of those for A and B, 1/2 for C |
| Guy strand, conductors | Safety factor 2 |
| Anchors (uplift) | Safety factor 1.5 |
| Vertical allowance | 300 lb at one end of one crossarm (Rule 46) |
| Setting depth | Table 6: 6 ft for a 45 ft pole in firm soil; utilities set about 10 % of length plus 2 ft |
Where guys are needed, GO 95 Rules 49.1-A(2) and 49.6-C require them to carry the entire lateral load, with the pole below the attachment acting merely as a strut; the anchor rod must be as strong as the guy. The pole is then checked at and above the guy. This tool also shows how a stiff pole and its guys share the load, as O-Calc does, and uses the larger guy tension.
Common configurations
Words used on the job
| Tangent | A pole on a straight run of line. Spans on both sides balance; wind is the main load. |
| Angle | Where the line changes direction. Double arms on the bisector and a guy against the resultant pull. |
| Dead-end | The conductors end and their full tension is held by strain insulators. A double dead-end holds spans from both sides independently, so a switch can be put between them. |
| Buck arm | A crossarm at right angles to the line arm that dead-ends a tap or the second leg of a corner. Not to be confused with a buck-boost transformer, which adjusts voltage. |
| Alley arm | A side arm that holds all conductors to one side of the pole, used along property lines and alleys. |
| Riser or dip | Where underground cable comes up the pole to connect to the overhead line through cutouts and terminations. |
| Class | The ANSI O5.1 strength rating of a wood pole. Lower numbers are stronger; H-classes are stronger still. |
| Lead | The horizontal distance from the pole to the guy anchor. A longer lead puts less tension in the guy. |
| Joint use | A pole shared by the power company and communication companies, each in its own space. |
| Climbing space | A clear square kept up one side of the pole so a lineman can climb past conductors. |
| Pole loading analysis | The calculation on the Wind loading tab, usually done for design with O-Calc or similar software. |
| Utilization | How much of the allowable strength the loads use. 100 % is the GO 95 limit with its safety factor. |
References
Rules and material standards
- CPUC General Order 95, Rules for Overhead Electric Line Construction (December 2024): Rules 37, 42-49, 54, 56, 58; Tables 1, 2, 3, 4 and 6; Appendix F
- ANSI O5.1-2022, Wood Poles: Specifications and Dimensions, Tables 5 and 8
- RUS Bulletin 1724E-150, Unguyed Distribution Poles: Strength Requirements
- SCJPC Routine Handbook, section 16 (joint-use space allocation)
- Southwire SPEC 80100 (ACSR) and SPEC 80120 (AAC) conductor data
Anaheim Public Utilities
- Construction Standards book (2026): CO 100-3A, CO 100-5A, CO 110, CO 130 series (guying), CO 200-1B, CO 210-5, CO 210-11, CO 210-12, CO 220-1, CO 435-1, CO 470-1, CO 604-10, CO 605, CO 610 series, CO 622, CO 626 to CO 628, CO 631, CO 780 to CO 783, CO 920-1, CO 925, CO 1101 to CO 1129, L135
- Design Manual DM 8 (pole loading limits, design tensions) and DM 9 (guying)
- GSA3 overhead design O-Calc models (for example poles 33519D and 33530D); GSA11 O-Calc guideline and basis of design
Other utilities
- LADWP Distribution Standards: C401, C403, C409, C442, C443, C445, C448, C451, C480, C490, C500; P223, P291
- SCE Distribution Overhead Construction Standards: DC 200, DC 320, DC 500, DC 510, DC 540, DC 550, DC 570, DC 580, DC 610; AC 120.1
- PG&E Electric Overhead Construction: 015202 (crossarms), 015225 (cutouts), 022088 (pin insulators), 022178 (guys), 022221 (anchors)
Analysis
- O-Calc Pro analysis reports (GO 95), Anaheim GSA3 and GSA11 archives, used to check this calculation
- GO 95 Appendix examples for crossarm and pole loading