Quick Answer
High-tensile wire fence works best with corner posts 8 feet deep, brace posts every 8–10 feet within the H-brace, and line posts 60–80 feet apart on flat terrain. Reduce line post spacing to 40–50 feet on moderate slopes and 20–30 feet on steep terrain. Fiberglass sighter posts can be added between driven posts to maintain wire height on sagging terrain.
Corner Post Requirements
Corner and end posts are the structural anchor for the entire fence. They must be set in concrete or well-tamped gravel at 3.5–4 feet depth. Minimum diameter: 5–6 inches for treated wood. The post must extend at least 4 feet above ground after setting. A post that shifts even 1–2 inches causes significant loss of wire tension across the entire fence run.
Line Post Spacing Table
| Terrain Type | Spacing | Post Type |
|---|---|---|
| Flat, open | 60–80 feet | T-post or fiberglass |
| Gently rolling | 50–60 feet | T-post or fiberglass |
| Moderate slope | 40–50 feet | T-post preferred |
| Steep slope | 20–30 feet | T-post + driven in slope |
| High livestock pressure | 30–40 feet | T-post preferred |
| Curved fence line | 25–35 feet | T-post with drive stakes |
Why High-Tensile Can Use Wider Spacing
Standard barbed wire or woven wire sags significantly between posts and requires 15–20 foot spacing to maintain proper wire height. High-tensile wire's higher carbon content and proper tensioning (200–250 lbs) keeps the wire taut over 60–80 feet without sagging. The wire acts somewhat like a spring — it deflects under livestock pressure but returns to position without permanent deformation.
Sighter Posts
On undulating terrain, wire may sag between driven posts on high spots and pull too tight over low spots. Add lightweight fiberglass sighter posts at the high/low transition points to guide the wire. These require no driving — just push them in by hand. They hold wire height without the cost or labor of a full-strength driven post.
Our Recommendation
Use 60-foot spacing as your default on any moderately flat to rolling terrain. Survey the fence line before ordering posts — terrain changes that require closer spacing are often limited to 20–30% of the total run. Using 60-foot spacing except where terrain requires less saves 30–40% on post cost for a typical installation.