how-it-works.html

HOW THE ENP WORKS

The original ENP was designed around a Wildcountry Rock Number 3 NUT. The rock 3 is used sideways on its smallest side. This nut used in the ENP would have a breaking strength of approximately 6Kn = 600 kg or 1300 lb.

Super ENP's
Most of the routes described here use the original ENP, Rocks 3. The dimensions of the actual ENP were recently changed to take into account its use on climbing walls and for sports routes. Used in these activities the original alloy nut would be far to soft and would wear very quickly. We also had another problem in that the hole we used (a 22 mm hole) was rather too large for climbers who used electric drills or hand drills. The Super ENP now uses a brass nut similar in size to the RP 5( which can also be used) . The hole required for this model is now only 18 mm and far easier to drill by any method. Using the RP 5 nut raises the breaking strength of the nut to 9Kn - 1800 lbs Using brass for the nut also reduces wear in case of repeated falls .

We are at the moment trying to get a dedicated nut made with a thicker wire which will bring the breaking strength up to in excess of 13 kn. The wire will be shorter - you fall less distance- and is more easily placed and retrieved.
Using the ENP also removes the need to have an extra extender, as you would normally do when using a nut.
A wire placed into an ENP is captive and can not come out accidentally as they some times do when placed in a crack.

The ENP design
Basically the ENP is a steel tube, one end of which has been formed to fit a particular size of climbing nut. In this tube is a small stainless steel spring in front of which is a hard plastic stopper/washer. When you place the nut into the tube of the ENP the nut pushes against the plastic stopper , by continuing to push the nut you depress the spring backwards . This allows you to turn the nut sideways through 90 degrees.. By releasing the nut the spring forces the nut forwards and traps it in the pre-formed sides of the tube. The ENP will work even if the spring should ever break as the spring itself has no part to play in the strength of the ENP; it is only there as a retaining force. ENP's are placed into the rock at a downwards angle . This stops any water or dust entering the actual tube. It also presents a kinder profile on which the wire rests.

How does the ENP stay on the rock?
The ENP is placed into a pre-drilled 18 mm hole and is then fixed with Sika or Hilti resins. The shape of the ENP is so designed that it will resist any effort to withdraw it. The tube is widened at its base and has deep depressions at certain points which when filled with resin become fixed to the surrounding rock. Like all chemical fixings careful placement is very important and the manufacturers instructions should always be followed. At the time of writing ENP's have withstood a force in excess of 12 kn . None have come out of the rock and in fact all the wires which were used for testing broke.
The strength of the ENP is dictated by the strength of the nut and wire you place in it.

Using nuts in the ENP
Climbing nuts, particularly the smaller ones such as sizes 1/2/3 and 4 have a tendency for it to slide up the wire. It is advisable to eliminate this sliding which can be done in a number of ways after pulling the nut down hard on the wire.
1. Tape the wire just below the nut.
2. Fix the nut onto the wire by resin or Apoxi glue.
3. Picking the wire by punching the alloy in the same area as the wire. Fixing the nut on the wire also has advantages when placing and removing climbing nuts in difficult crack.

When climbing routes with ENP's select the nut/nuts you are going to use ( I usually paint them ) and fasten a crab to individual nuts. Plugging into ENP's with your wires set up like this is as efficient as clipping bolts. BUT ------------ENP's are not bolts

ENP's are not bolts they are just the same as all natural protection systems , you must make sure that they are sighted well and have been turned through 90 degrees and that they are fitting correctly into the slots of the ENP. Once sited correctly they will not come out. You must make sure that they are sited correctly by visually seeing that they are

All new nuts should have there corners worn slightly. I do this by rubbing the corners of the nut on sand/emery paper. This allows the nut to turn more easily within the tube of the ENP. If your climbing nuts have been used for any length of time you will not need to do this.

Retrieval.
Under normal circumstances you can simply remove the wire in the reverse order. Push the wire backwards into the ENP, turn through 90 degrees, and let the spring push it out.
If the wire has withstood any force than the nut may be wedged in , just as in a crack. Move the wire upwards and downwards to release it and it should then be easy to remove. If it has taken a very long, and perhaps life saving fall, then you may have to remove it with a narrow nut key, just as you would with a nut. The only time we have ever had one stuck was under test condition when we were testing it to destruction, and even then by using a nut key it was possible to retrieve the nut.