Mike Holt Enterprises Understanding the NEC

Keeping up with the requirements of the Code should be the goal of everyone involved in the electrical industry. The 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.

Sizing Raceways Using Annex C [2020 NEC]

The content below is extracted from Mike Holt's Electrical Exam Preparation textbook, based on the 2020 NEC

Click here or on the thumbnail to the left to view or download the PDF of this rule. (5 pages, 1.03 KB)

Click on the image above to watch the video

When installing conductors of the same size in a raceway, do you know how to determine how the number of conductors permitted in a specific conduit or tubing?

Well, one way is to do the math and divide the area of a conductor into the fillable area of the raceway. But why do that when the tables in Annex “C” have done the work for you? These tables simplify the process but you need to be sure to consider the information in the notes that precede the tables as they can influence the actual number of conductors that can be installed in a particular raceway.

If any of this sounds confusing, read the text and watch the video as Mike and a team of experts explain.

• • •

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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888.NEC.CODE (632.2633) www.MikeHolt.com
Mike Holt Enterprises, 3604 Parkway Boulevard, Ste 3, Leesburg, FL 34748
"... as for me and my house, we will serve the Lord" [Joshua 24:15]

Comments
  • Mr. Holt I have a small electric company in Louisville, KY mainly residential and light commercial In many occasions I have enjoyed your videos. My company has grown --specially last few years. I normally only hire NON experience people, and trained them. However, I am not a good teacher. Do you have a video program That i could purchase that would explain the code book starting from chapter one. hopefully an video around 1 hour. I will like to maybe have a weekly class for all my employees

    paul  December 30 2022, 11:19 am EST
    Reply to this comment

  • Tables are great.Found over the years best practice on long runs or runs with 270 degrees or more best to use the next size conduit. Years ago we had a chief electrician that seldom bothered with tables. We were wiring in 19 pumps along with cold, hot & temperature controlled water to keep water marketed chocolate pipes from freezing ( around 89.5 degrees F for milk chocolate ). Anyway ran over 30 #16 gauge wires ( for water solenoids ) & #14 gauge for 480 volt 1/2 & 3/4 HP Pumps. Pull was thru 360 degrees and of course even though we used a lot of wire lube in the undersized EMTVwe ripped nylon jacket off of a lot of wires. Back in the early 1970's we pulled all wire by hand. Would use mogul LB'S. even used 2.5 & 3" LB'S with a threaded 2.5 or 3" to 2" threaded reducer. A lot of times we used THW wire instead of far superior THHN/THWN.Companies do not realise that its often cheaper to spend a little extra on next size conduit and that results in labor savings.

    garbo  December 30 2022, 1:38 am EST
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