Wrapping a rod set onto a conductor is only half the job. The half that decides whether the assembly stays tight is fanning. Each rod is grouped, started, and worked outward so the finished wrap grips evenly instead of bridging or binding.
Our order desk regularly receives photos from crews standing at the pole, asking whether a finished wrap counts as a good fan or needs to come off. The difference is always the same handful of details: subset size, center-mark alignment, pitch, and end stagger. This page is the checklist we send back, built around the manufacturer application procedure that governs preformed armor rods.
What Fanning Means on a Preformed Rod Set
Armor rods are factory-formed helical wires, matched and packed in sets. Fanning is the field technique that turns a loose bundle of rods into one graduated sleeve. The rods are split into working groups, started together at the center mark, and wrapped outward so their ends land in a controlled stagger rather than a jumble.
The name is literal. Done correctly, the finished rods spread and taper away from the support point the way you fan a hand of cards. Each rod sits one step offset from its neighbor, ends roughly even, with no rod trapped underneath another. A crossed rod buried mid-fan cannot be corrected after the set is closed, because preformed rods are single-use devices.
Fanning also controls electrical grading, not just mechanical grip. An even fan distributes the bending and abrasion protection along the support, and on higher-voltage lines it keeps the rod ends from concentrating stress at one point. Manufacturers offer smooth PARROT-BILL style ends specifically to meet corona and RIV requirements on EHV systems, and a careless fan defeats that geometry.
Read the Rod Set Before You Fan
Every rod in the set carries a center mark, and the set itself is color coded by conductor size. Before anything touches the conductor, hold the bundle flat and confirm three things. No rods may be crossed, the center marks must line up across the bundle, and every rod must come from the same factory set.
That last point is a formal rule in the application procedure, not a preference. The instructions state that armor rods are factory matched and packed in sets, and that rods from different sets must not be mixed. Two half-sets from different conductor sizes will never close into a uniform fan; the diameters differ enough to leave the assembly loose over some strands and tight over others.
Check the lay of the rods against the conductor as well. The preformed helix must follow the conductor’s lay direction, so a set formed for right-hand lay cannot be fanned onto a strand pattern running the other way. If the rods resist closing against the strands, stop — resistance at this stage means the wrong set, not a technique problem.
Split the Set Into Balanced Subsets
A full set is too many rods to control in one pass. The manufacturer’s general recommendation is to apply no more than one-half of the rods per set at a time on smaller sizes. On conductors 4/0 and larger, apply no more than 4 rods at a time. Those working groups are the subsets that make fanning manageable.
Form each subset by holding its rods flat with center marks aligned and ends even, then twist the bundle until the rods take up their formed lay as one unit. The procedure describes twisting the lay of the rods until the subset is formed — the rods should move together, not unwind individually.
Keep the subsets balanced. If the set has eight rods, that means two matched groups of four, not a group of six and a group of two. Unbalanced subsets produce an asymmetric fan: one side of the support builds up rod thickness faster, and the finished wrap seats harder on that side.
Start at the Center Marks and Fan Outward
Mark the support point on the conductor first, using a felt marking pen or lumber crayon. The procedure is explicit that the conductor should not be scratched, because a scribe mark works the conductor under vibration. Place the subset’s center marks at that point and apply at least one full wrap before anything else.
That first wrap is the anchor of the whole fan. With both legs started at the center, the subset can then be worked outward leg by leg, alternating between sides so the two halves of the set advance together. The hot-application instructions describe the same rhythm: after both subsets have been started, work them alternately out to the ends.
The center mark also bounds where the fan may sit. The procedure limits center offset to no more than one pitch length from the center of the support point. A set applied a pitch off still looks finished, but the rods are then shielding the wrong span of strand, and the support point itself is left uncovered.
Hold Pitch and End Alignment While Wrapping
Pitch is the helix step of the formed rods, and it is the reference for everything measurable in a fan. The center mark sits one pitch length from each rod end on the drawing, so keeping the wrap’s pitch undistorted keeps every other dimension honest. A stretched or flattened pitch means a rod was bent during application, and bent rods never close back to form.
End alignment is where fanning earns its keep. The application procedure gives hard numbers. Rod ends should be maintained within 2 inches of each other for voltages of 230 kV and lower, and within 3/4 inch for 345 kV and above. The stagger between individual rods creates the fan; the tolerance limits how far that stagger may drift.
| System Voltage | End Alignment Tolerance | What a Violation Signals |
|---|---|---|
| 230 kV and lower | Within 2 inches | Uneven subset working or a crossed rod |
| 345 kV and above | Within 3/4 inch | Corona and RIV performance at risk |
| Any voltage | Center offset ≤ 1 pitch length | Support point left unprotected |
Fan Over Repairs and Hot Applications
Fanning changes slightly when the set covers a damaged conductor or is worked on an energized line. In repair situations the manufacturer procedure calls for surface preparation across the full rod length. Wire brush the damaged conductor, then apply a gritted inhibitor before the first rod goes on. Skipping the inhibitor traps grit and oxide inside the fan, where the abrasion the rods were meant to prevent continues unseen.
For hot-line work with a pin or hold stick, the subsets are phased deliberately. The rod ends of the first subset sit on top of the pin, and the second subset starts with its rod ends beneath it so the two subsets phase properly. Only after both subsets have been started do they get worked alternately out to the ends — the same alternate rhythm as a ground-level fan, with rigging constraints added.
Two equipment facts complete the picture for planners. Single and double support lengths are available, so the fan length can be matched to the span’s vibration exposure rather than chosen by guesswork. Within a high-temperature suspension clamp, the rods carry a continuous thermal rating of 250°C. That margin is why ACSS repair applications accept the same set that a 125°C ACSR repair uses elsewhere.
Judge the Finished Fan Before You Leave
Picture the finished wrap at arm’s length before you call it done. A correct fan shows a slight, even gap between adjacent rods along the whole covered length. That gap is the acceptance signal in the manufacturer’s examples: after application of the correct number of rods, a slight gap between the rods should be present.
The failure modes are graded in the same examples. A wrap with rods touching everywhere is rated merely satisfactory but usually means an unneeded rod was added. An extra rod that bridges over its neighbors creates a bridging condition and potential rod abrasion. The worst case combines an extra rod with an expanded tube condition, which affords little protection and allows severe abrasion of both conductor and rods.
In our experience the last check crews skip is the end snap. Each subset should be closed with a firm twist that snaps the ends into place, and every rod end must snap fully. An end left half-seated works loose under vibration and opens the fan from the tip inward. The procedure’s tie-breaker rule is worth repeating verbatim: when in doubt, leave it out.
Fanning Defects That Quietly Damage Conductors
Most armor rod failures trace back to fanning errors rather than bad hardware. The defects below are the recurring ones, each with the mechanism that makes it expensive later.
- Too many rods at once. The procedure warns that a damaged conductor can result from applying too many rods together, which is why the half-set and 4-rod limits exist for larger conductors.
- Distorted rods. Bending rods during application leaves the assembly loose on the conductor, and under vibratory conditions that looseness can cause severe abrasion to both conductor and rods.
- Crossed rods. A rod trapped beneath its neighbor cannot be re-seated without removing the set; crossed rods are the single most common reason a half-fanned wrap must be scrapped.
- The tube method. Threading the whole set through a tube is explicitly not recommended, because it distorts the rods and damages the conductor it is meant to protect.
- Hardware placed over the fan ends. When tapping clamps are needed, keep the clamp at least six inches from the rod ends, with inhibitor and wire-brushed surfaces in the clamp zone.
When a defect is found, the remedy is removal and a fresh set, because preformed rods are single-use products intended for one application on a specified conductor. Fanning a suspect set back into shape on the pole is not a repair; it is the beginning of the next failure. Crews that want the full surrounding procedure — tools, conductor prep, and seating — can follow the site’s complete armor rod installation guide alongside this one.
Frequently Asked Questions
What does fanning actually do on an armor rod set?
Fanning staggers the rods from the center outward so the set grips evenly, keeps the helix pitch undistorted, and leaves the slight inter-rod gap that marks a correct, abrasion-free wrap.
How many rods can be applied at one time?
Apply no more than half the set at once on smaller conductors. On 4/0 wire and larger, apply no more than 4 rods at a time to avoid damaging the conductor during fanning.
Is a gap between rods a good sign or a fault?
A slight, even gap is the acceptance signal. Rods touching everywhere suggest an extra rod; bridging or an expanded tube condition means the fan needs to come off and be reapplied.
How closely must the rod ends line up?
Within 2 inches for 230 kV and lower, and within 3/4 inch for 345 kV and above. The set center must also stay within one pitch length of the support point.
Can rods from different sets be fanned together?
No. Rods are factory matched and packed in sets, and mixing sets is prohibited. Preformed rods are single-use, so a disturbed or mismatched set is discarded, not reused.
Fanning rewards patience. Mark the center, trust the color code, work balanced subsets alternately to the ends, and accept the wrap only when the slight gap and end tolerances are both visible. Done that way, the rods bed down once and stay there for the life of the conductor. RaxPower packs every armor rod set factory-matched and color coded so that the fan, not the hardware, is the only variable a crew has to think about.