You work for an electrical services firm. One of its clients is a small shop that doesn’t have an actual maintenance department. Three employees and the two owners keep the equipment running the way a “shade tree mechanic” keeps cars running. Their work is passable but not professional because they aren’t trained electricians or mechanics.
A few months ago, the client bought a custom-built production machine with the goal of increasing revenue about 25%. The firm that sold them this built it from old machines bought on liquidation and installed it on the premises. Before the machine arrived, your firm had installed a transformer and panel near the intended location of the machine. The custom builder accepted responsibility for running the branch circuits needed for the machine.
This machine has experienced many unscheduled shutdowns, all of which seem related to the controls. The custom builder has sent a tech out twice, but the problems persist. In frustration, your client asked your firm to send someone out to look things over and advise.
Walking past the machine to the panel with one of the owners, you notice a ground rod installed with a bare copper wire running from it to the machine. The owner notices your gaze and says, “At least it’s not a grounding problem.”
At the power distribution panel, you noticed several of the blanks were missing and the slots were empty. The panel also had several unused knockouts missing; in fact, all of the ones on one side were missing. Something odd struck your eye. You noticed raceway inside the panel was secured by a locknut, but there was no EMT connector on the outside of the panel and yet the raceway was connected with EMT connectors. Upon closer inspection, you noticed the raceway was IMC not EMT. But instead of being assembled with threaded couplings it was assembled with a mix of pipe fittings and tubing connectors.
The panel-related errors alone would not explain the problems your client was facing, but at this point, you have learned all you need to know. What is it you know, and how should your client proceed?
Answer to Quiz. The violations of Sec. 110.12(A) are a big red flag that competence is not this builder’s strong suit. The use of pipe fittings on raceway violates Sec. 110.8. IMC cannot have its mechanical integrity if assembled with connectors intended for tubing, so the use of those violates Sec. 110.3(A) and (B). There are threadless connectors for conduit, but you don’t use them on threaded conduit (unless they are specifically listed for that purpose). And you don’t use tubing connectors with conduit.
What does all of this mean? If they got these things wrong, they certainly got other things wrong, such as that ground rod, for instance. Due to the raceway errors, they probably do not have electrical continuity in the raceway, so it’s unable to serve as a decent equipment grounding (bonding) conductor — but that ground rod doesn’t, either. Any time you see a ground rod driven next to a utilization load, think of it as the smoke that shows you there’s a fire. Grounding on the load side serves no electrical purpose, but it may introduce a tripping hazard. That ground rod needs to be removed.
Custom-built machinery is not a bad way to go. In addition to the cost-savings that it typically brings, the end-user gets exactly what is needed to do the job. The typical custom machine builder is versant in the NEC, has a qualified person design the electricals, and has a qualified person oversee the electrical installation — and the same goes for the mechanicals.
Had this client done a little due diligence ahead of time to find a qualified custom machine builder, this thing would be running like a Swiss watch. And there’s the solution to recommend. Trying to fix the many errors that likely exist in this system would become an expensive game of whackamole. The best course of action is to find a qualified custom machine builder who can examine what this client has in terms of major components, then provide a proposal for correctly putting them together into a system.
