The Right Stuff
More Downtime is Better?
NEC at the Facility
Tomorrow's FREE Conferences
Answer to Electrical
About This Newsletter
e-newsletter is brought to you from the
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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
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The Right Stuff
How do you know if you're doing the right
maintenance? The answer begins with understanding why your maintenance
department exists. See if you can correctly answer this multiple-choice
The maintenance department exists to:
Which answer did you pick? Were you thinking, "All of the above?" If
that is incorrect. You can see why by examining each of the choices
- Keep equipment in perfect working order.
- Do preventive maintenance.
- Repair things that break.
- Keep product flowing out the door.
A. Keep equipment in perfect working order. Equipment needs
be in good working order. Perfect isn't realistic.
Equipment that is within specifications doesn't need adjustment or
repair. This assumes, of course, you have the correct specifications.
B. Do preventive maintenance. Preventive maintenance is a
means, not an end. By definition, it involves doing things to
equipment. Anytime you do things to equipment, you risk causing
premature failure. For example, you don't pay a garage to run your car
up and down a lift, or do endless inspections and adjustments. You pay
them to keep your car running smoothly. The less preventive maintenance
needed to keep equipment running smoothly, the longer your equipment
C. Repair things that break. Although the maintenance
department typically performs repairs, repairing isn't its reason for
existing. Otherwise, it might make sense for every maintenance manager
to go around breaking things so that the maintenance department has
repair. The job isn't to repair -- it is to maintain.
Maintenance performance is graded by the absence of breakdowns
rather than how many get fixed.
D. Keep product flowing out the door. This is the reason the
production department exists. The maintenance department exists to
support that effort.
To determine what the right maintenance is, you need to be keenly
aware of which equipment is vital to product flow (making it "critical
equipment") and what maintenance actions prevent breakdowns.
Complicating matters is the fact that some product flow is more
important than other product flow.
A 400A breaker has tripped four times this week. Your
"secret weapon," the power monitor, has finally let you down. For some
reason, it failed to capture any triggering events. What's going on?
The answer to this question appears at the end of this
More Downtime is
The traditional view of maintenance is that less
downtime is better, but this isn't always true. Sometimes, you should
choose to allow more total downtime of production equipment.
However, the company pays its bills by selling products. How can
increasing overall downtime be anything but counterproductive?
The answer lies in the fact that resources are limited and not all
downtime is of equal value. Let's use an example to illustrate how this
works. The company makes Widget-A, Widget-B, and Widget-C.
From this, you can see that not all downtime is of equal value. On
occasions when you don't have enough resources to go around, you need
know which product(s) the company most needs to move out the door. Ask
the production people regularly, not just when an emergency arises.
- The profit on each Widget line is $120, $180, and $14,
- The average daily unit sales are 95, 70, and 8, respectively.
- The company can barely keep up with demand on Widget-A orders. It
has a three-day supply of Widget-B units and a 10-day supply of
In the example, suppose you can fix the Widget-B line 15 minutes
faster if you have two people handing tools to the repair crew. But
leaves the Widget-C line down without maintenance support for 3 hours.
Is that extra 15 minutes of Widget-B uptime worth 3 hours of Widget-C
downtime? You bet! Will the Widget-C supervisor agree? Probably not.
Don't try to placate the Widget-C supervisor by spreading out your
resources. This practice leads to plant closings.
On the other hand, don't lower yourself into the stew kettle. To
out of hot water, ask the other production supervisors to meet with the
Widget-C supervisor and review the numbers. Unless that Widget-C
supervisor loves job hunting, you'll get the agreement you need. Nobody
with common sense tells the plant manager, "I held down our total
revenue to make my own numbers look better."
NEC at the
Suppose you're adding a convenience receptacle at the
operator station for a process control system. Per the installation
manual, this system has its own ground rod. The drawing provided for
receptacle shows the receptacle grounding terminal wired to a bus that
connects to that rod. Should you install per the drawing, or should you
run a separate ground wire back to the panel where you connect the
neutral and hot?
The receptacle needs an equipment ground, not an earth
An earth ground is for lightning protection. You can't use it for the
receptacle ground. Run the separate ground wire. While you're at it,
make sure that ground rod is bonded back to the power source. This will
fix the many Article 250 violations that exist if it is not.
Assume any of the following during an electrical test,
and you may not live to conduct another:
- "I don't need to check my test equipment unless there's a problem."
It's a little late to inspect test equipment, especially test leads,
after you've already been electrocuted. Check before you connect.
- "All grounds are the same." An equipment ground is part of the
bonding system, not the earthing system. Connect to the wrong ground,
and you may be shocked at what you find -- literally.
- "Nobody else is at risk if I inject a high voltage now." Verify
everyone is clear and that cables and equipment are properly
Show & Events
Make plans now to take part in the next round of
FREE live conferences in the EC&M E-Tradeshow. These
events will take place tomorrow, April 12th!
Visit the exhibitors in this virtual tradeshow before and after the
conferences and check out the On-Demand Theater, where you can view
online conferences any day and time of the year.
- "Electrical Power Engineering: Industry Shortcomings and
Solutions," presented by John DeDad, Senior Director, Editorial and
EC&M Development [9:00 a.m. Eastern and Pacific time]
- "The Mighty Hand-Held Power Meter!" presented by Michael
Daish, Summit Technology [10:00 a.m. Eastern and Pacific time]
- "Understanding Generator Reliability," presented by Mike
Kirchner, Sales Training Manager, Generac [11:00 a.m. Eastern and
Click here for
information on accessing the EC&M e-Tradeshow and attending
FREE live conferences.
Electrical Troubleshooting Quiz
Rest easy. Your trusty friend hasn't let you down. The
power monitor has shown you that the failure isn't due to a triggering
event. This narrows down your troubleshooting considerably. The cause
probably a worn mechanism inside the breaker. Because the frame alone
probably more than $1,000, consider the economics of having an
authorized shop rebuild the breaker.
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