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Wednesday, August 26, 2015
Question:
In your reply to a question the other day, you mentioned terminations and referenced 110.14. My question is related to terminating on wire-binding screws in 110.14(A).
From a code perspective and/or your respected opinion, rather than wrapping a stranded wire conductor around a screw, would it be best practice to terminate it with a crimp-on terminal (i.e. sta-kon or the like) before attaching to a device?
Steve Manak
A
Answer:
Hey Steve thanks for your question. Conductor splices and terminations are considered by many to be frequent failure points. Wire binding screws, studs and nuts with upturned lugs, or the equivalent are permitted for 10AWG and smaller conductors as stated in 110.14(A) as you mentioned. Cup washers with screws are an example of an equivalent method. Following the instructions that are included with listed equipment is required as stated in 110.3(B). So if listed electrical products are provided with a wire binding screw that is probably the best method to use. Using a crimped connection can also be done and could reduce the likelihood of problems related to strand containment. You need to make sure that the separate pressure connector used is compatible with the terminations of the electrical equipment and that its use does not create a problem with how the manufacturers design. Improper torqueing is also a common problem at terminations.