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I once had a conversation with a salt mine manager looking to turn off ground-fault protection of motor protection relays. Surprised, I politely asked why. He said, “I know I have a ground fault. When salt builds up on the terminals ground fault currents flow and trip the relay. I don’t have a budget to clean the salt off, but I do have a budget to replace the motor. So, I’m looking to burn the motor up along with the conductors.” I was stunned. This was a manager at a major corporation who believed his only option was to destroy expensive equipment because he lacked the funds to maintain it.
This story comes to mind when I talk about the latest changes in NEC Article 700. The language in NEC 700.3(C) for emergency systems was expanded to ensure that systems are maintained in accordance with manufacturer instructions and industry standards. This helps assure that testing procedures for emergency transfer switches, overcurrent protection device cycling, along with equipment supplying smoke detectors, emergency lights, elevator mechanisms and other safety devices are followed. This revision in the code, which is yet another great step for safety, got me thinking. What about maintenance for power distribution systems beyond those designated for emergency?
I liken system-wide maintenance to caring for an automobile. The owner’s manual lists all the important upkeep aspects over a car’s lifespan. Most of us have the routine stuff down, like changing the engine oil every 3,000 miles. But how many of us change the radiator fluid after the first 60,000 miles, or the differential fluid, or the spark plugs? All are recommended by car manufacturers but are usually ignored or forgotten.
Maintenance is a “just-get-it-done” situation that has safety implications.
Similar maintenance shortcomings can happen in our industry. For instance, the NEC tells us to recalculate fault current and incident energy after making changes to the distribution system, such as when motors are added or subtracted. But most don’t do it. Maintenance always seems to be the last item thought of when a project is scoped and rarely afforded a budget after installation.
It’s important that companies regularly perform upkeep. Using the same car maintenance analogy, do you enjoy visiting a mechanic for an oil change only to find out you need to flush the radiator, change the transmission fluid, install new brake pads and maybe replace the shocks? Of course not. Just like a car owner, many in our line of work simply don’t plan for things to go wrong.
Maintenance is a “just-get-it-done” situation that has safety implications. And, while not explicitly stated, some sections within NEC code imply general safety maintenance. For instance, NEC Section 90.1’s “Purpose” section contains all-encompassing language stating that, if systems are to perform as intended, all devices must be installed, maintained and free of hazard as outlined by manufacturers’ instructions. But, in my opinion, few codes offer enough guidance for specific products or scenarios. There’s nothing in NEC 210.8 , for example, that says ground-fault circuit interrupter (GFCI) breakers and receptacles must be tested monthly (which I’ll bet few in the industry realize). Only manufacturer instructions provide that guidance.
Following all manufacturer instructions is extremely important because, when it comes to maintenance and other issues outside of installation requirements, there’s no Authority Having Jurisdiction (AHJ) in most cases. Maintenance of electrical equipment has a direct tie to safety and is interwoven into the fabric of NFPA 70E. Think of the electrical worker who reads an incident energy label to determine what level of PPE is needed for the justified energized work about to be performed. The incident energy value on the label is dependent upon an upstream overcurrent protective device working as it was designed and intended to function by the manufacturer when it left the factory. The manufacturer has maintenance instructions to help ensure that device will function as it is intended when called upon to do so. If proper maintenance is not performed as specified, the incident energy value that the worker dressed for could very well be wrong and the worker could be underdressed for the occasion should an arc flash incident occur. It’s all about safety. Ignoring maintenance places workers, your facility, your business and your livelihood at risk.
So, what can be done to prevent maintenance issues?
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