Some basic protective-device principles

When you hear “protective device,” think “breakers” and “fuses.” It’s one thing to know how to size them correctly. It’s another thing to know why. But it can be expensive to learn the “why” . . . .

Breaker sizing is a critical element of what nuclear electrical engineers do, but the subject is so deep that the details can overwhelm someone who is unfamiliar with the basics. Consider a statement from IEEE 242-2001, which says (about itself): “[t]his recommended practice is not intended as a replacement for the many excellent texts available in this field.”

IEEE 242 (which refers to itself as a “recommended practice”) is titled “IEEE Recommended Practice for Protection and Coordination of Industrial and Commercial Power Systems,” and it’s over 700 pages long. It goes for around $170 brand new (if you get the PDF only).

The “Blue Book,” one of the “excellent texts” which IEEE-242 alludes to, is titled “IEEE Recommended Practice for Applying Low-Voltage Circuit Breakers Used in Industrial and Commercial Power Systems,” and is another 200 pages and goes for between $50 and $125 used online, depending on market conditions at the time.

That’s not to mention the old college textbooks you might have sitting on your shelves that may contain a chapter or two about the subject. You probably paid upwards of over $100 for those.

That’s why only the tip of the iceberg is scraped here. Nevertheless, this basic introduction to protective devices, with specific focus on their use in the nuclear power industry, will serve a new electrical engineer better than if he had none at all.

To read on, click here.