Tech Forum

NRG offers rock anchors in 3 sizes:

1. 15"
2. 30"
3. 53"

These anchors are 1.75" and the widest part and need a 2" diameter pilot hole drilled at least 6 inches less than the length of the anchor (the length measurement includes the eye that the guy wires are run through - this will keep the eye above ground level):

• For the 15", drill 2" diameter a hole 8" - 9" down.
• For the 30", drill a 2" diameter hole 23" - 24" down.
• For the 53", drill a 2" diameter hole 46" - 47" down.

It is a good idea to tape the expanding end of anchor before trying to insert the anchor into the hole to test to see if it is drilled to the correct length.  This keeps the end from expanding and becoming stuck in the hole before you are ready for it to be expanded:

When ready to expand the rock anchor, remove the tape, insert the anchor until it hits the bottom of the pilot hole, and twist clockwise by inserting a rockbar or piece of rebar into the eye of the anchor.  Turn until you feel the anchor start to slightly bend - STOP IMMEDIATELY and align anchor eye horizontally to the ground.

 What length rock anchors should be used for a 50M XHD TallTower?

The part of the rock anchor that expands and holds is the same for all of our rock anchors, but different length rods are available.  If you are installing into solid rock that is covered by 1 meter of soil, you will need to order a longer rod version of the rock anchor.  However, if the rock into which you're anchoring is exposed and not buried by soil, you can order the shortest rod version of the rock anchor.

 Thanks a lot for the info,..very helpful