Maintaining for Energy
Savings, Part 4
NEC in the Facility
Answer to Electrical
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MRO Insider addresses topics such
Working with management and supervision
National Electrical Code® on the production floor
Safety procedures and programs
Equipment maintenance and testing tips
Managing motors and generators
Trends in training and education
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The designations "National Electrical Code" and "NEC" refer to the
National Electrical Code®, which is a registered
trademark of the National Fire Protection Association.
Energy Savings, Part 4
Correcting power factor and installing variable drives
reduces energy waste in air-handling systems. To push system efficiency
further, answer these two questions:
Pushing conditioned air into spaces where it’s not used (e.g., above
the ceiling) means your system must condition more air to maintain the
desired temperature and humidity. Duct leakage is the primary cause of
this waste. Ductwork can leak at every joint, and often those joints
aren’t readily accessible.
- Are you using all of the air you’re pushing?
- What load are you pushing against?
In older facilities, one “solution” to excessive leakage is to
“upgrade” to larger air handlers (e.g., replace a 15-ton unit with
20-ton unit). The resulting mismatch between blower output and ductwork
capacity lowers efficiency and nearly always degrades temperature
Rather than oversize the blower, reduce the leakage. Due to
accessibility issues, performing a comparative flow analysis to
determine the leakiest runs is a recommended approach. Where you have
access to the ductwork, however, you can use your thermal camera to
exact locations of leaks — a job made easier during the heating
season. Fixing just these leaks is a fast, inexpensive way to get
results. It might even make the other work unnecessary.
Now, what about that second question? Where a system has high back
pressure (load), the culprit is almost always poor filter maintenance.
Keeping filters clean also reduces duct pressure ahead of the filter
thus reduces upstream leaks.
Question: How do you know when to change air filters?
Answer: Set up pressure monitoring across the filters and tie this
your building management system for an automated alert.
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Over the past few weeks, you’ve received numerous
complaints about “nuisance breaker trips” from office personnel.
affected circuits supply employee workstations in various departments,
such as accounting and customer service. Each time you go to examine
affected panels, you discover “someone” reset the breakers before
you got there, making this a safety problem as well.
The facility has a power monitor watching the feeders, and no
anomalies appear in the logs. You took some voltage measurements at a
few receptacles and found things to be normal. Why are those breakers
The answer to this question appears at the end of this
Equipment never breaks down on a set schedule or in an
orderly fashion. Some days, it seems everything breaks at once. On
days, what do you fix first?
Set your equipment priorities based on plant safety and revenue
Your safety-related systems and equipment are clearly identified (or
should be), so what about revenue flow? What exactly is that?
A production plant makes revenue by shipping product. Work In
Progress (WIP) flows through the plant the way water flows through a
piping system. Every plant has certain “pipes” through which
everything must flow.
At some point in the system, a particular pipe limits flow though
entire system. Elihu Goldratt (author of “The Goal,” an operations
management book) refers to this pipe as “the bottleneck.” When you
have to choose what to repair first, safety comes first. Next in line
are those revenue-restricting bottlenecks.
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NEC in the
A site can contain both Class I and Class II locations.
Confusing the two can be easy, so take care that doesn’t happen.
The seal requirements for Class I locations [501.15] are more
detailed and extensive than those for Class II locations [502.15]. The
difference is this: Class I addresses the presence of combustible (or
flammable) vapors, while Class II addresses the presence of
combustible dust. It’s much harder to control vapors than
so Class I requirements are more stringent than Class II. If the
location has vapors, apply Class I.
Even legal drugs can have catastrophic consequences in
electrical work. You don't want to be slow to react or hyperactive when
working on live circuits or equipment. Some common examples:
What should you do?
- Antihistamines. If the label says it “may” make you
drowsy, don’t take it before or during work.
- Decongestants. Typically, a decongestant speeds up your
entire system. Its effects are comparable to those of other stimulants,
such as coffee or diet pills.
- “Energy” drinks (e.g., Jolt, Red Bull). It’s safer to
overcome “the drowsies” by going to bed earlier rather than by
- Always read the label and use as instructed. If in doubt, ask a
- If you’re taking other medications, ask a pharmacist about drug
- If you’re on any medications, let your supervisor know. If
something happens and you’re unconscious or incoherent, this
information may save your life.
Electrical Troubleshooting Quiz
The timing is a good clue. We’re now into winter, so
don’t be surprised if you see personal space heaters tucked under
One downside of “going green” is that some companies embrace it
by lowering thermostats too far. No longer kept warm by an efficient
central heating system, occupants resort to point-of-use heaters and
often supplement them with small coffee makers. This typically results
in a rat’s nest of daisy-chained surge strips and extension cords.
What about the nuisance trips? Count up all of the loads on each
circuit (including coffeemakers kept in desk drawers), to determine
which breakers are being overloaded. These should be tripping
replace any that aren’t. To correct the overload, you must correct
One choice is to add more circuits to accommodate the heaters and
other devices. Another is to simply turn up the thermostat. The first
choice will require an investment in labor and material, and it will be
more energy-consumptive than achieving the same effect per the second
choice. Management needs to decide if it wants the appearance of
green based on an unrealistic thermostat setting, or if it wants to
actually be green.
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