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.

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

Whether you are an apprentice learning for the first time or are studying to take a licensing exam, knowing how to determine the exact maximum ampacity of an electrical conductor is a crucial requirement to ensuring a safe and adequate installation. Conductor ampacity values [Table 310.16] must be corrected when the ambient temperature is not between 78°F and 86°F and must be adjusted when more than three current-carrying conductors are bundled together. The temperature correction multiplier [310.15(B)(1)] and adjustment multiplier [310.15(C)(1)] are applied to the conductor ampacity, based on the temperature rating of the conductor insulation as contained in Table 310.16, typically in the 90ºC column. And then there is the temperature limitations for terminations [110.14(C)] to be considered as well. Confused? Watch this video clip extracted from our Electrical Exam Preparation course as myself and a panel of experts, walk you through each of the factors involved in the process of accurately calculating conductor ampacities in compliance with the National Electrical Code®. 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. (1 page, 415 KB) Click on the image above to watch the video

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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