Wind turbines that are smaller than 60 inches (1.5m) can be secured with "screw" augers. Bigger wind turbines require augers set in concrete. Screw-in anchors can be set in dense clay, gravel and sand as well as hard silt. If you are unsure, use concrete. A 4ft (1.2m) deep hole with 2.5ft (0.8m) diameter can take 2 feet (0.6m) of concrete to ensure that the auger helix is covered while giving the required holding strength. The anchor must be securely fixed below the local area's frost level to avoid "jacking" (the tendency of buried objects to push upwards during freeze or thaw). The concrete hole must be lined with rebar for good support.

The anchor should come out of the ground at a 45° angle, pointing straight at the tower's center, to ensure equal bending force through the guy wires. Otherwise the anchor will lose its strength when it bends up or down over time.

Guy Wires

Guy wires may come with the tower kit or can be purchased separately in bulk rolls, according to your needs. Extra strong steel cables are recommended to support the tower. Check the tower manufacturer's manual for the required diameter of guy cable for the type of tower and turbine size. A general estimate is 14 inches of extra high strength steel cable for components offering 3kW output, with a tower of 100ft (30m).

The guy wire length is dependent on the height of the tower and the anchor's distance. The length of the guy wire from different heights to the anchor is calculated using Pythagorean Theorem (9th Grade Trigonometry).

The tower and the ground should form two triangle sides with a 90° intersection. The hypotenuse (long edge) of the triangles formed by the guy wire using a 60-foot (18m) tower is 55ft (17m). The radius of the guy wire is half of the tower's height (30ft or 9m). From this:

(Tower Guy Height² + Guy Radius²) = Guy Wire Length

Therefore:

(Tower Guy Height² + Guy Radius²) - Guy Wire Length
= (552 + 302) = V (3,025 + 900) = 62.5 ft (19 m)

This is the exact distance between the anchor and tower. You should allow an extra 5 feet (1.5m) for misalignment and for securing the guy wire to the tower and anchor brackets.

When you have determined the guy wire lengths, carefully roll out the cable straight on the ground. Kinking can cause the wire to become useless. Make sure you wear the right type of eye protection to protect yourself from whipping cables.

The guy wires can be connected to the anchor and tower with preformed cable grips or "U" bolts. The former are preferred for their easy adjustability.

Bigger wind turbines need guy wires to be very tight, with turnbuckles. Once the cables are tightened, thread a guy wire cable or safety chain through the turnbuckle to handle possible loosening. 

Smaller units with small rotors (60 inches or 1.5m diameter) need not have turnbuckles. Pull the guy wires tight with a cable puller before using clamps.