Striking a Balance
Fast vs. Good vs. Cheap
NEC at 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
Managing energy use
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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.
Striking a Balance
How do you know if you're doing too much or too little
maintenance? How do you know if you need to do less of some tasks and
more of others? These questions all center around maintenance
The answer differs, depending on such factors as:
These factors, and others you must consider, are interactive. Striking
the right balance to optimize the maintenance
requires good judgment and sometimes plain luck.
- Which piece of equipment you're talking about. Putting all
equipment on the same schedule might be the easy thing to do,
But it makes no sense technically, and it wastes labor and other
- The conditions under which that equipment is operating. The
manufacturer's recommendations assume normal usage. But are your
conditions normal? Harsh duty means accelerating those schedules, while
light duty may allow you to stretch those out.
- The age of a given piece of equipment. Maintenance schedules
that were fine for new equipment are probably not adequate as that
equipment ages. Small damage accumulates. For example, insulation
deteriorates over time. That's a key consideration for your insulation
resistance testing program and motor maintenance program.
- The maintenance procedure itself. Due to conditions, the
scheduling of one procedure may need to be accelerated while another
- Maintenance and repair history. This is a key element in
"condition-based maintenance" and "predictive maintenance," which have
established good track records. Be careful you don't read too much
between the lines. While you can predict failure from measured
or past results, you have to allow for those contributing factors you
didn't measure or observe.
- Risk tolerance. How much will one downtime incident cost
company? How does this affect your personal job security?
In our next issue, we'll look at questions that center around doing
the right maintenance, rather than how often you do
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A major production line went down, due to loss of a
motor. The motor had been in service for many years. When you
disconnected the motor leads, you noticed they were stiff. They also
left a black residue on your hands. This motor is one of several on
line, and all of these motors get an annual inspection. Based on what
you found, what further troubleshooting is called for on this line?
The answer to this question appears at the end of this
Fast vs. Good vs.
Most repairs happen under the pressure of unplanned
downtime, where speed is of the essence. But experience teaches us that
when it comes to good, fast, and cheap, you can have no more than two
these simultaneously. Since "fast" is a condition of downtime, you have
to balance quality and price when doing repairs. But what if you could
remove "cheap" from the equation altogether? While this may seem like
wishful thinking, you can make it a reality.
The single most potent constraint in this process is not a technical
one. When things are humming along just fine, production managers are
looking for ways to squeeze out more profit. That invariably means
cutting costs. So the idea of spending, for example, $3,500 for a spare
that will cut the repair time of a critical piece of equipment by 80%,
likely to fall on deaf ears while goods are moving out the door.
When equipment is down, production managers have only one thing in
mind. They want production restored. With no production, revenue goes
zero while fixed costs still need to be paid. In this situation,
production managers are very motivated to sign off on an expenditure
that will prevent a recurrence. Wait until the day after production is
restored, and they are once again focused on cost cutting.
What's the first key to getting adequate funding for training, spare
assemblies (rather than just spare parts), test equipment, and other
items that reduce "time to repair" without sacrificing quality? It's
getting a commitment when the gatekeepers are over the proverbial
barrel. In our next issue, we'll look at some specific ways of doing
NEC at the
If you have a requirement to install an isolated ground
(IG) receptacle, what's the right way? First, understand that an IG
receptacle is just a normal receptacle with the yoke not bonded to the
receptacle grounding lug. This allows you to put the equipment ground
for that receptacle on a separate bonding path.
406.2(D) requires the IG receptacle to be marked with an orange
triangle, which is easy enough to comply with. But 406(D)(1) refers you
to 250.146(D). That's where things get interesting. An IG does
not have its own ground rod. An IG is merely an insulated
path that runs, eventually, to the same grounding point as the other
equipment grounds in the facility.
Never make the following assumptions when working in
- "The confined entry permit addresses all possible dangers."
Actually, the permit addresses the dangers related to gases. It does
necessarily address other dangers. It's just one element of a total
safety protocol for that particular space.
- "If others have been working safely in the confined space, then
there's no need for me to read the permit." This assumption fails
two counts. First, conditions change. The permit that was valid this
morning may not be valid now. Second, the permit often contains
information that each person entering the space needs to know. Read it
carefully. If there's anything you disagree with or don't understand,
discuss it with the entry supervisor.
Electrical Troubleshooting Quiz
You have discovered one of the reasons for not using
time-based preventive maintenance. The stiff leads and black residue
signs of insulation breakdown, which is a natural consequence of age.
Because one motor has failed due to this cause, the remaining motors
probably marginal. Get a schedule in place to conduct insulation
resistance tests on each of the remaining motors -- the sooner the
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