This can be a confusing topic. The issue usually arises in nuclear power plants because most cable is rated at 90 degrees C, but equipment terminals are rated for 60 or 75 degrees C. Getting this wrong leads to costly rework down the line. Continue reading “Cable ampacity – insulation temperature rating vs. equipment terminal ratings” →
The National Electric Code is officially adopted as legal building code in 47 states. It is also adopted by local governments in their official building codes. But to buy a new copy costs around $100. Some say you should be able to download the NEC 2014 for free, online . . . .
Continue reading “Download the NEC 2014 for free ?” →
Installing cables? Then you’ll probably be installing conduit, too. Here’s a five-step procedure for determining the correct conduit size . . . .
Continue reading “Conduit sizing” →
You may not know that the National Electric Code doesn’t make complying with its voltage drop criteria mandatory. But there are still some important design factors that you need to keep in mind . . . . Continue reading “The importance of limiting voltage drop” →
There are numerous ways to go about doing this. Here’s one that is sure to work. It’s concise: five steps . . . . Continue reading “A five-step cable sizing procedure” →
Choosing a breaker based on its trip setting? Careful. You might need to make some adjustments . . . . Continue reading “Breaker temperature ratings” →
Cables can be purchased that are rated for different temperatures. The three most common conductor temperature ratings are 60ºC, 75ºC, and 90ºC . . . . Continue reading “Cable temperature ratings – it’s all about the insulation” →
Here are three common scenarios that you need to keep in mind when sizing a new cable. Its ampacity will have to be derated depending on how these three factors apply to you . . . .
Continue reading “Derating cable ampacity – count the ground or neutral?” →