When using the double-twist method, a minimum diameter of 0.032-inch wire should be used on parts that have a hole diameter larger than 0.045 inch. Safety wire of 0.020-inch diameter may be used on parts having a nominal hole diameter between 0.045 and 0.062 inch with a spacing between parts of less than 2 inches. Note that these specs are for steel wire designed for safety wiring and not aluminum, copper, or brass wire.

Safety Wiring Procedures
There are many combinations of safety wiring with certain basic rules common to all applications:

1. When bolts, screws, or other parts are closely grouped, it is more convenient to safety wire them in series. The number of fasteners that may be wired together depends on the application.

2. When self-locking nuts are used, their respective bolt heads need not be safety wired.

3. Ensure that the finished safety wire is tight to prevent failure due to rubbing or vibration.

4. Safety wire must be installed in a manner that will prevent the tendency of the part to loosen.

5. Over-stressed safety wire can break under vibration if twisted too tightly. Safety wire must be pulled taut when being twisted and maintain a light tension when secured.

6. Safety wire ends must be bent under and inward toward the part to avoid sharp or projecting ends, which may present a safety hazard.

7. Before safety wiring fasteners, check to see that they are torqued to spec and that the wiring holes are properly aligned to each other.

Securing screws, nuts, bolts, and snap rings.
The safety wire is shown installed for right-hand threaded hardware. For hardware with left-hand threads, the safety wire is routed in the opposite direction.

Using Safety Wire Pliers
While safety wiring can be done by hand, it is commonly done using a pair of safety wire pliers. These are similar to traditional pliers, except they feature a center shaft and pull knob that allows the user to hold on to the pliers while they twist the two strands of wire together by pulling on the knob. This ensures a taut fit against the fastener, keeping it from coming loose when wired in conjunction with another fastener or fixed point.