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Maintenance
Procedure
Reconciliation, Part Two
In Part One, we looked at eliminating procedural
inconsistencies inside the CMMS. Now we'll look at eliminating
inconsistencies in procedures as they are practiced.
Your first step is to use the CMMS to identify a high maintenance
item. Then, see which three people do the most of that maintenance and
consider them your subject matter experts. These two steps are all
you'll use your CMMS for, here. This use of the CMMS allows you to
focus
your efforts where they'll do the most good.
Your next step is to take notes on how each person does the
maintenance. You want to come away with a series of numbered steps put
in simple terms, to describe how each person does this job. The notes
for one person might begin as follows:
- Measure voltage.
- Measure current.
- Open disconnect.
- Measure starter contact resistance.
If the three people do things the same way, congratulations! If not,
you'll need to reconcile the variances. Begin by compiling two
lists:
- A list of steps that all three experts did.
- A list of steps that only one or two experts did.
Now, call your experts together and try to get consensus on which steps
from the second list should be added. Refer to specific information in
the manufacturer's maintenance recommendations, during the discussion.
Once you've added the "should add" steps to the first list, you have
reconciled three different "as practiced" procedures.
You can use a similar process to address the sequence. Why does Joe
do X first and Louise do Y first? If the sequence doesn't matter
technically, your personal preference is probably fine.
The point of all this is to remove variances from procedures so that
they are consistent and are performed consistently. If
two
approaches are equally valid, choose one and do it that way.
Procedural inconsistency builds suboptimal performance into a
system.
Procedural consistency "designs out" suboptimal performance.
Consistency
doesn't mean you can't improve procedures later. In fact, improvement
is
more likely when everyone is working from the same page.
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Repair
Electrical
Troubleshooting Quiz
A critical piece of equipment has gone down due to
failure of the drive motor three times in the past year. The repair
logs
show the same problem, but time to repair was 3.7 hours, 2.2 hours, and
4.4 hours, respectively. It seems obvious that the first two repairs
weren't done correctly, or the third would not have been needed. But is
a fourth repair on the horizon?
The answer to this question appears at the end of this
newsletter.
Repair Scripts: The
Flowchart
In our previous issue, we described how to create
checklists that help a technician quickly check for likely failure
causes. Another approach is the flowchart. Flowcharts can be wonderful
troubleshooting aides, but there are two potential problems:
- They can become so convoluted that people won't use them.
- The development process can become overwhelming.
The solution to both problems is the same: keep things simple. But how
can you do that if the equipment itself is complex? Use the drilldown
approach. Fortunately, the drilling down is already done for you.
Develop flowcharts from the relevant electrical drawings, starting with
the one-line.
Basing the flowcharts on the drawings reduces the work involved in
developing flowcharts, and produces flowcharts that are consistent in
structure to existing information. Tip: If you note the relevant
drawing
number for a given decision or action bubble on the flowchart, you tie
information together and make the job easier for the technician.
But if you already have the drawings, why create additional
documents? Wouldn't a flowchart be redundant? No. The flowchart focuses
on the decisions you have to make and the steps you have to take. The
drawing provides information that a person uses to develop a mental
flowchart anyhow.
When you use a drawing during troubleshooting, you are making yes/no
decisions and then deciding what step to take next. Having this mental
work already done will save time and reduce errors, especially during
high-pressure downtime situations.
A good flowchart is easy to follow and contains minimal text on the
page. It works best when it serves as a quick visual guide. If you make
it too comprehensive, it won't be useful. Don't try to flowchart the
system for every possible problem. If your flowchart identifies the
most
likely problems, it serves its purpose.
Operation
NEC at the
Facility
If you install a switch in a metal enclosure, you're
supposed to "ground as specified in Article 250" [404.12]. If you're
using nonmetallic enclosures with metal raceways or metal-armored
cables, you must make provisions for "grounding continuity." However,
driving a ground rod next to the enclosure would not be part of
complying with 404.12. The key is "as specified in Article 250." In
404.12, the NEC means bonding (Article 250, Part V), not grounding. See
Article 100 for the definitions.
Unsafe Assumptions
In our previous edition, we identified three unsafe
assumptions. Here are two more:
- "If something is grounded, it's safe to touch." This arises
from the false perception that grounding puts everything at the same
potential. Per NEC Article 100, "grounding" means making an earth
connection and "bonding" means making a metallic path. The resistance
of
earth is too varied and too large to eliminate differences of
potential.
Bonding is the only way to accomplish this.
- "If you're conducting thermography or just taking a few
electrical measurements, then arc blast protection isn't
necessary."
This assumption implies that a blast-producing fault will somehow know
what you're doing. The truth is an arc blast can strike at any time, no
matter what you're doing. Protect yourself based on an arc blast
analysis, not on a task analysis.
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Litigation
Don't miss the live conference Claim Litigation: Bolstering Your
Case presented by John DeDad, senior director, editorial and
EC&M development, scheduled for March 15th. Learn how to
retrieve
costs resulting from undesirable and/or unplanned working conditions
that are beyond your control. Find out how to document various claim
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exhibition and live conference center.
Quiz Answers
Answer to
Electrical Troubleshooting Quiz
This situation has "procedural inconsistency" written
all over it. Other than the fact it took longer and presumably was more
thorough, you have no assurance that the third repair was correct.
People are not working from the same page. That is the problem you need
to solve so that future repairs can be evaluated against actual
performance.
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