The NEC requires each ungrounded service conductor to have overload protection [Sec. 230.90]. And you can’t insert an overcurrent protection device in a grounded service conductor unless it simultaneously opens all conductors of the circuit [Sec. 230.90(B)].
Hey, this sounds great. You just need a panel with the correct overcurrent protection devices (OCPDs) at your service and, because that meets Code, you’ve done all you need to do. Right?
In an industrial facility today, leaving out a power monitoring system when specifying the service equipment is almost always a poor decision.
And what about those OCPDs themselves? You could specify the cheapest ones that meet the rating and consider that good cost control. And for this project it would be. But over a few years, it would prove to be a costly decision.
If the plant is intended to operate for forty years or more, it’s a really bad decision. You’ll understand why when you look at the features of the more advanced breakers.
