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Underwriter's Knot (Electrician's Knot)
Underwriter's (Electrician's) Knot TyingForm a loop using the first wire. With the second wire, form a loop around the first and pass the tail through its loop. Attach the wires to their terminals. Strain on the cable is now taken by the knot.
Underwriter's (Electrician's) Knot Details
Origin: This knot was described by Ashley as a Wall Knot of two strands which he recommended for electricians expecting rough treatment (ABOK # 237, p 44.) It is known as the Underwriter's Knot – presumably because fire underwriters know that the strain relief reduces the risk of fires and electrocution.
Tying it: The two strands wrap around each so that each strand exits the knot away from the standing end. This is the same technique employed when tying a Wall Knot.
Strain Relief: When finished and installed, the knot should be snug against the housing and both terminal leads should have a little slack. Then, strain on the line is taken by the knot and does not affect the connections.
Disclaimer: Any activity that involves ropes is potentially hazardous. Lives may be at risk - possibly your own. Considerable attention and effort have been made to ensure that these descriptions are accurate. However, many critical factors cannot be controlled, including: the choice of materials; the age, size, and condition of ropes; and the accuracy with which these descriptions have been followed. No responsibility is accepted for incidents arising from the use of this material.