Terminal Post Distances
The distance between terminal posts can greatly affect the distance between line posts. The terminal posts are the corner, end and gate posts. If your terminal posts are 30 feet apart, you should set your line posts 10 feet apart, typically the maximum distance your line posts should be apart.
Depending on the length of your wire fence, you can put line posts up to 20 feet apart. When you're installing steel or wood posts, you can use 15-foot spacing.
The smaller the distance between line posts, the sturdier the fence will be. Depending on what you are using your fence for, greater distance may be acceptable to use.