Keeping up with the requirements of the Code should be the goal of
everyone involved in electrical safety. Following is what I feel is an
important rule in the 2020 NEC®, complete with
graphics and a video. I encourage you to use it as a training resource for
your organization, and share it with your colleagues.

Conductor Insulation [310.4] |
The content below is extracted from
Mike Holt's Electrical Exam Preparation textbook, based on the 2020 NEC.
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The movement of electrons through an electrical conductor (current) creates friction and that friction creates heat. The NEC tells us that all normally current carrying conductors must be insulated and that insulation must be rated to be able to handle the heat created by the current without melting! The insulation rating is indicated by letter designators that not only identify temperature ratings, but also suitability of the conductors when used in various locations such as wet or dry, in direct sunlight, or other special applications. Then on top of all of this, there are voltage ratings to be considered as well!
There are many variations of letter designators (˜TW', ˜THHN', ˜RHW-2', just to name a few) and these are required to be indicated on the insulation covering. But, what do these letters mean? How do I keep track of them all? What voltage are the conductors rated for?
Fortunately, the NEC helps us with all of these questions in Table 310.4(A) (Conductor Applications and Insulations) and for even more help with this extensive Table, read the attached text, study the graphics, and watch the video as me and a panel of experts, breakdown everything you need to know about conductor insulation!
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Click here or on the thumbnail to the left to view or download the PDF of this rule to follow as you watch the video. (3 pages, 414 KB)
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Click on the image above to watch the video
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We'd
love to hear from you about this series, and the ways you're using it.
Send us your comments and feedback by clicking on "Post a Comment"
below. Look out for the next part in this series a month from now, and
please share with your colleagues. |
This content is extracted from Mike Holt's Illustrated Guide to
Electrical Exam Preparation, based on the
2020 NEC Program.
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