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What a lot of people don't realize is that the foundation for understanding the NEC rules for electrical installations is electrical theory! Whether you're a first-year apprentice still struggling to understand the difference between a volt or ampere, or a veteran electrician trying to sharpen your troubleshooting skills, this product has something for you.
We're sharing this clip from the program to introduce you to the importance of this topic. Please feel free to share this with your friends and co-workers, and for more videos and content on this topic, check out our Electrical Theory Video Library that includes the full program and digital textbook.
The content below is extracted from Mike Holt's Understanding Electrical Theory for NEC Applications textbook.
| Overcurrent Protection, Time-Current Curves |
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Click here or on the thumbnail to the left to view or download the PDF. (2 pages, 2.18 MB)
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Click on the image above to watch the video
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Did you ever wonder how long a 25A load placed upon a 20A overcurrent protective device will take to trip? The time it takes for the overcurrent device to trip depends on a number of factors, one of which is the “time-current-curve characteristic” (TCC) of the specific overcurrent protective device. A time-current curve (TCC) chart has a vertical side that shows the time in seconds it will take the device to open relative to the current in amperes as shown on the bottom of the chart.
To learn more about time-current-curves and characteristics, read the attached text and watch the video where Mike and a panel of experts discuss this topic. Click on the image to the right to watch the video and be sure to download the PDF to follow along.
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For more information on this topic, get a copy of Mike Holt's Understanding Electrical Theory video program and textbook.
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