Electricity runs the equipment that technicians and installers in the hvacr profession work on daily. Extreme caution must be used when working around electrically powered systems. Grip paralysis can occur from feeling as little as 10 mA (milliamperes). (See Table 1.)

It is imperative that electricity be treated with the utmost respect. It should never be taken for granted. When approaching your work assignment, always be aware of the electrical components around you. Think safety first.

Note: The following information is not intended to be an all-inclusive electrical safety checklist. Use it to help think about your involvement with electricity and as a framework to develop your own electrical safety procedures.


Working safely around electricity is a mindset. Approach every job using good common sense and incorporate safety procedures that become as close to you as your Leatherman. The following are important reminders:

  • Remove rings, watches, and jewelry.
  • Wear safety glasses.
  • Wear a hard hat, electrically insulated rubber gloves, and rubber-soled shoes.
  • Do not wear loose-fitting clothing.
  • Use a rubber mat when working in front of equipment or electrical panels.
  • Always treat de-energized circuitry as if it were energized.
  • Pursue electrical safety training.
  • Help others to become aware of the dangers of electricity.


    Power and hand tools are a technician’s best friends. Tools and meters should always be treated with tender loving care to ensure that they are in good working order. Look for and replace power cords that are frayed, nicked, or broken. When using a meter to test either current or voltage, make sure the meter is set at the proper range to be measured. In addition:

  • Use third-party approved, three-wire extension cords with ground and ground fault circuit interrupters (GFCI).
  • Never use an ohmmeter in an energized circuit.
  • Use electrically insulated hand tools.
  • Use double-insulated power tools.
  • Always use the right tool for the job.


    Where we work is as important as what we work on. A jobsite that is strewn with unnecessary clutter and debris can be a dangerous place to work. Organize your work area. Organize your tools. Do not let them become scattered about. As this practice becomes habit, you will notice an increase in productivity and efficiency. Furthermore, by developing a more systematic approach to the task at hand, you will be able to think with more clarity. As your thought process improves, so too will your performance. Sometimes there may be no control over the environment you work in. Proceed with caution and common sense. Allow for proper and safe clearances to electrical panels, wiring, and moving components.

    Some tips to remember:

  • Strive to work in a clean and clutter-free environment.
  • Avoid standing in or near water.
  • Do not reach out or lean over electrical lines.
  • Do not set up a ladder over electrical lines.
  • Make sure an area has been checked for electrical lines prior to digging.


    There are times when electrical measurements must be taken with the equipment energized. Do not attempt to perform these procedures unless you are trained and qualified to do so. Proceed with care and caution every time. Never take energized equipment for granted, no matter how many times you have worked on it in the past. In all other cases, turn the power off before working on the equipment. It is a good safety practice to padlock the electrical panel or disconnect and tag it (lockout/tagout) prior to working on the equipment. In addition:

  • Measure voltage at the unit with an electrical test meter.
  • Recheck for voltage at the unit.
  • Repair or replace broken wiring.
  • Tighten and secure all electrical connections.
  • Use correctly sized fuses and breakers.
  • Check for proper grounds.
  • Discharge capacitors by shorting a 20,000-ohm, 5-watt resistor across the terminals.
  • Do not take voltage, continuity, or current measurements at compressor terminals in a pressurized system.


    I repeat: Think safety first. Hammer this principle home until it becomes an ingrained mindset. Develop and craft yourself a personal set of electrical safety procedures and follow these procedures at all times.

    Publication date: 01/21/2002