Electrical Maintenance | 4 Rules

When considering the maintenance of electrical equipment, look into the wide variety of operating conditions in which electrical equipment is found. These conditions vary from normal room temperature and humidity to below freezing and above boiling temperatures. Electrical equipment operates in normal atmospheres, in explosive atmospheres, under water, in dust, and in other environments.

To minimize downtime and keep electrical equipment operating relatively trouble-free, you only need to remember four rules:

Keep it clean.
Keep it dry.
Keep it tight.
Keep it friction-free (if appropriate).

The most common cause of electrical failure is dirt. Dirt could be an accumulation of daily dust, it could be metallic filings from a nearby process, or it could be in the form of fibers, chemicals, and other materials. Often, dirt buildup provides an undesired path for current flow. This current leakage can cause equipment breakdown and failure. Also, dirt buildup can clog ventilation openings, causing heat buildup. Built-up heat can cause insulation failure and equipment breakdown as well. Whenever an inspection is performed, thorough cleaning of the equipment is essential.

Keeping electrical equipment dry is essential for the proper operation of the equipment. Corrosion or rust can form from high humidity or moisture. Although this may cause mechanical binding, corrosion or rust of conductors may cause a high-resistance connection, resulting in heat buildup and failure. In addition, moisture may act as a current path, causing an inadvertent short circuit. Some liquids react with the material used as insulation on conductors, eventually breaking down and destroying the insulating qualities. Also, moisture tends to attract dirt. As previously mentioned, dirt buildup can also lead to failure.

Mechanical vibrations cause electrical connections to loosen over time. Loose electrical connections can create high-resistance connections that result in heat buildup and failure of the termination. Often the termination becomes intermittent. Loose connections can be very difficult and time-consuming to find. To the naked eye, the connection looks good—the screw is in place, and the wire is between the screw and the terminal. Unfortunately, the mechanical connection is loose. It is good practice while performing an inspection to spend a few extra minutes tightening all connections to save hours later trying to locate the loose ones.

With the exception of braking functions, electrical equipment operates relatively friction-free. Failure of electrical equipment may occur if a mechanical bind or higher-than-normal friction exists. This may result in an overload condition, which may create nuisance tripping of overcurrent protective devices. It is good practice when performing an inspection to verify that all electrical equipment can operate with low friction.

When all is said and done, a simple checklist that is suitable for use on any type of machine can be a good reminder to help ensure that the proper checks are made. Before beginning any work, the appropriate PPE should be worn and the power should be removed from the machine to be inspected. The power source should be locked out and tagged out in accordance with your facility’s policies and procedures. When inspecting a machine, the following items should be inspected and then cleaned, dried, and tightened as appropriate:

Remove dust, dirt, and debris from within enclosures, boxes, cabinets, and wherever else it is appropriate.
- This can be done by wiping with approved cleaning agents or solvents or by vacuuming.
Ensure that all unused openings in enclosures, boxes, and cabinets are properly closed.
- Repair or replace as necessary.
Ensure that safe, proper, and required working clearances are maintained around all enclosures, cabinets, equipment, and machinery.
- Do whatever is necessary to restore required clearances.
Inspect components, conductors, and terminations for damage, discoloration, and evidence of overheating.
- Repair or replace as necessary.
Inspect for loose components and terminations.
- Tighten to specifications as necessary.
Check all push buttons, switches, circuit breakers, contactors, motor starters, and so on.
- Verify proper working condition with no mechanical binding.
- Repair or replace as necessary.
Verify that all overcurrent protective devices and thermal overload devices are properly sized and correct for the application.
- Repair or replace as necessary.
Verify that all overcurrent protective devices, disconnects, and so forth are correctly, legibly, and properly labeled.
- Repair or replace as necessary.
Inspect the condition and proper support of wire raceways.
- Repair or replace as necessary.
Inspect the flexible cords for condition and proper strain reliefs.
- Repair or replace as necessary.
Verify that all documentation is up to date and accurately reflects any changes, modifications, and additions to the equipment or installation.
- Update or modify documentation as necessary.
Remove lockout/tagout and restore power.
Verify that all indicators (lights, alarms, etc.) are functioning properly.
- Repair or replace as necessary after again performing a power shutdown, lockout, and tagout.

The above article is an extract from our NEW Fast Trax® Magenta Course. Check it out HERE for more information.

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Four Rules of Electrical Maintenance

Electrical Maintenance | 4 Rules