Boosting Your Maintenance
Reduce Downtime Through
Practical Implications of OSHA
NEC on the Production Floor
Answers 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
National Electrical Code®, which is a registered
trademark of the
National Fire Protection Association.
Here are a couple of tips to maximize your maintenance
Schedule GFCI testing. Do you have a GFCI testing program? If
not, people in your facility are at higher risk for electrocution than
they otherwise would be. Just because the receptacle still provides
power doesn't mean it provides GFCI protection. Testing a GFCI
doesn't take long -- the real problem is doing it in the first
In low-risk applications (e.g., a seldom-used receptacle in a
low-traffic location), the odds may let you "get by with" a lax testing
program for years (then again, they might not....). In high-risk
applications (e.g., a receptacle next to an often-used sink), failure
have frequent testing is a bit like playing Russian roulette with only
one empty chamber.
Power events rank high on the list of GFCI failure causes. Following a
power event, you should test GFCIs (prioritize by risk level). If your
power monitoring system notifies you when an event occurs, you can
initiate the tests in a timely manner. Here's a new strategy: As GFCIs
fail, replace them with the self-testing models that have recently
appeared on the market.
Solicit operator input. Because operators spend far more time
than maintenance people observing equipment operation, operators are
potential goldmines for attentive maintenance organizations. An
can inform you of strange noises and smells, odd vibrations, and other
signs of trouble -- under actual operating conditions.
An operator may suggest a different configuration or process
that will reduce wear and tear. Such a suggestion may include equipment
modifications to reduce unnecessary process steps -- which also
output. Increased output is a selling point to department managers when
you are trying to obtain the downtime needed to implement the change.
Here's a quick tip: Ask individual operators to explain the process and
how it might be streamlined.
Showing operators that you respect them and value their input will
encourage them to provide information and ideas from a perspective you
simply do not have. This multiplies the brainpower of your maintenance
organization -- at no cost to you. Yes, you'll have to filter out some
"unusual ideas," but you'll also get gems you would otherwise miss.
AutomationDirect now offers the Cutler-Hammer
Enhanced 50 series of high-performance photoelectric sensors,
manufactured by Eaton, with prices starting at $44. Thru-beam,
polarized reflex, diffuse and clear object models are available, with
sensing ranges from 45 inches to 500 feet. All sensors are IP67 rated
and are available with a variety of cabling choices. Visit www.automationdirect.com/photoelectric.
A 100-hp motor has tripped its overloads three times in
the past week. What are four possible causes, and how should you test
In a previous issue, we said you could reduce downtime
by training a team on specific repair activities. But another answer is
to move some repair activities "offline" from the downtime
At one appliance plant, a critical assembly would throw a bearing every
six to eight months, causing the entire output of the plant -- $250,000
an hour -- to stop. It took three hours to remove the assembly, rebuild
it with new bearings (the one that failed and its mate), and reinstall
the assembly. But less than half an hour of that repair involved
removing and reinstalling the assembly.
Maintenance solution. With a complete assembly as a spare in the
stockroom, the repair downtime would drop from 3 hours to 30
minutes. While one team removed the old assembly, another team would
retrieve and lubricate the replacement assembly. A new assembly cost
$35,000 -- about 8 minutes of downtime. Total savings: about $1.3
million a year. Actual outcome: These savings didn't materialize
because the division VP was obsessed with a stockroom inventory number.
So the company continued to incur a $1.3 million loss every
Assuming your management has its eye on the right goals, you can apply
this mechanical example to electrical situations and realize a huge
savings. Where you have electrical assemblies, you have an opportunity
to reduce downtime. Added savings tip: Many electrical distributors
think along these same lines, and one may already have a
solution waiting for you. Move assembly work outside the downtime
window, and you reduce downtime.
For Quick Motor
Decontactors are a combination plug & receptacle and disconnect
switch. They allow electrical equipment to be safely and easily
disconnected and connected - up to 60 hp or 200A. Since there is no
access to live parts workers can change out a motor without having to
'suit-up'. Inquire about our free trial program.
Meltric Corporation, call 800-433-7642, www.Meltric.com
of OSHA 1926.150
This addresses fire protection. Most of the provisions
are one-time responsibilities or matters of policy. For example, once
you install a sprinkler system, you satisfy the requirement to install
one. But you still need to maintain sprinkler, alarm, and automatic
extinguisher systems. Other provisions require periodic action, too.
Manual fire extinguishers, for example, have these requirements:
NEC on the Production
- Check them, by type, for appropriate application to the area in
which they are located.
- Keep inspections updated and documented.
- Keep locations clearly marked and unobstructed from view and
Walk into the typical industrial or commercial
and an hour later you can walk back out with a hefty list of Art. 110
violations. In our previous issue, we discussed four common violations.
Here are four more:
- Inadequate lighting at service panels [110.26(D)]. You must
provide illumination for all working spaces about service equipment,
panelboards, and so on. Note the phrase "working spaces." This language
implies the illumination is there when you are working in that space.
Thus, providing the power source for the light from the same source as
the equipment makes little sense. Think about the application in terms
of illumination for work. What will it take to light that area so
can safely and efficiently service that equipment? While the answer may
go beyond the letter of the Code, the practical implications are clear.
And don't forget to provide receptacles for supplemental task
- Violation of dedicated space above equipment
[110.26(F)(1)(b)]. For some reason, the "dedicated space" above
electrical equipment seems to attract HVAC, water, steam, and other
utility pipes. What happens when you get a leak or a drip?
- Unguarded equipment [110.27(B)]. The sight of a transformer
bearing a "forklift scar" is all too common. Install bollards and other
hefty protection, as needed, to prevent physical damage to electrical
- No warning [110.27(C)]. If unauthorized people are entering
equipment rooms, they are needlessly exposing themselves to the
risk. Also, unauthorized people have a tendency to treat equipment
as storage closets. Post adequate signage. OSHA also requires limited
access to authorized personnel only -- via a lock
Electrical Troubleshooting Quiz
There are several other potential causes, though these four are
the most common. If a motor trips its overloads, you need to examine
motor system methodically--otherwise, you risk catastrophic failure. A
methodical investigation will address three areas: inputs to the motor
(voltage, current, waveforms, etc.); the motor (environment,
connections, balancing, alignment, mounting, etc.); and motor load
issues (gearbox lubrication, motor/load alignment, motor/load type
mismatch, etc.). NEC Figure 430.1 is a helpful guide.
- Wrong overloads. You can quickly eliminate wrong overloads
a cause. But don't increase the overload size just to prevent nuisance
tripping -- an appliance plant that did that put itself in a 9-week
shutdown. Use the correct overloads.
- Voltage imbalance. Measure voltage to ground on each phase.
If you have a variance of 2% or more between any two measurements,
distribution issues are killing your motor.
- Low voltage. Check the voltage at the motor input terminals.
The lower the voltage, the more current the motor will draw--this could
be what's tripping your overloads.
- Motor insulation problems. Damaged motor insulation is a
common cause of tripping, and of motor failure. Perform an insulation
resistance test on the windings.
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