ELECTRICAL SAFETY REQUIREMENTS
This section sets forth requirements for electrical safety. It specifically addresses working in restricted areas; working near exposed energized motor power lines and/or rotating parts; operating equipment near to or adjacent with other construction activities, working on electrical equipment and systems/sub-systems, personal/equipment protective grounding, temporary wiring disconnect and over current protection, ground-fault protection, hazardous locations and wet locations.
General Electrical Safety Requirements
All electrical work practices must comply with applicable safe work standards practice at site. While conducting the tests, a qualified person-one who is familiar with the installation and operation of the motor- should be present to energize, de-energize the equipment in accordance with established safety practices.
Identified Electric Hazards during the Test
Electric shock and burns. An electric shock occurs when electric current passes through the body. This can happen when touching an energized part. If the electric current passes across the chest or head, death can result. At high voltages, severe burns can result.
Arc-flash burns. An electric arc flash can occur if a conductive object gets too close to a high-amp current source or by equipment failure (for instance, while opening or closing disconnects). The arc can heat the air to temperatures as high as 35,000o F, and vaporize metal in the equipment. The arc flash can cause severe skin burns by direct heat exposure and by igniting clothing.
Arc-blast impacts. The heating of air and vaporization of metal creates a pressure wave that can damage hearing and cause memory loss (from concussion) and other injuries. Flying metal parts are also a hazard.
Falls. Electric shocks and arc blasts can cause falls, especially from ladders or unguarded scaffolding.
Electric Safety Principles – Energized Condition
- De-energize whenever possible.
- Plan every job. The approach and step-by-step procedures to complete the work at hand must be discussed and agreed upon between all involved employees before beginning. Write down first-time procedures. Discuss hazards and procedures in a job briefing with supervisors and other workers before starting any job. It is the employer’s responsibility to have or develop a checklist system for working on live circuits, if such a scenario arises.
- Identify the hazards. Conduct a job hazard analysis. Identify steps that could create electric shock or arc-flash hazards.
- Minimize the hazards. De-energize any equipment, and insulate, or isolate exposed live parts so contact cannot be made. If this is impossible, obtain and wear proper personal protective equipment (PPE) and tools.
- Anticipate problems. If it can go wrong, it might. Make sure the proper PPE and tools are immediately available for the worst-case scenario.
- Obtain training. Make sure all involved employees are a qualified electrical worker with appropriate training for the job.
Electric Safety Principles – De – energized Condition
Electrically Safe Condition
The most important principle of electrical safety is to assume all electric circuits are energized unless each involved worker ensures they are not. Every circuit and conductor must be tested every time work is done on them. Proper PPE must be worn until the equipment is proven to be de-energized.
- Voltage rated gloves and leather protectors must be worn
- Electrically insulated shoes should be worn
- Approved insulating mats
- Safety glasses must be worn
- The required Arc Flash PPE must also be worn
Conditions for Electrically Safe Work
- Identify all sources of power to the equipment. Check applicable up-to-date drawings, diagrams, and identification tags.
- Remove the load current, and then open the disconnecting devices for each power source.
- Where possible, visually verify that blades of disconnecting devices are fully open or that draw out-types circuit breakers are fully withdrawn or rack out.
- Apply lockout/tag out devices in accordance with formal written procedures.
- Test each phase conductor or circuit part with an adequately rated voltage detector to verify that the equipment is de-energized. Test each phase conductor or circuit part both phase-to-phase and phase-to-ground. Check the voltage detector before and after each test to be sure it is working.
- Properly ground all possible sources of induced voltage and stored electric energy (such as, capacitors) before touching. If conductors or circuit parts that are being de-energized could contact other exposed conductors or circuit parts, apply ground-connecting devices rated for the available fault current.
- During the tests, ensure the constant communication between field and control room personnel to facilitate remote or local shutting off of motors if any undesirable situations occur.