Testing and Test Facilities
Electrical testing hazards arise when specialty testing is performed on electric power lines and equipment to determine maintenance needs and fitness for service. OSHA requirements for testing and test facilities are found at 29 CFR 1910.269(o) and 1926.963.
Specialty testing refers to cable fault locating, large capacitive load tests, high-current fault closure tests, insulation-resistance and leakage tests, direct-current proof tests and other tests requiring direct connection to power lines. These tests include interim measurements using high-voltage and/or high-power methods on new lines and equipment, such as during commissioning activities, and on existing lines and equipment that may be in or out of service. Tests can be performed in laboratories and shops, typically identified as permanent test areas; in-field testing sites are typically identified as temporary test sites not guarded by permanent fences or gates.
Electrical testing hazards include high-voltage and high-power source hazards. Among the high-voltage source hazards are inadvertent arcing or voltage overstress destruction and accidental contact with objects that have induced voltages from electrical field exposures. High-power source hazards include ground voltage rise and exposure to excessive electromagnetic forces associated with the passage of heavy current. The purpose of the OSHA requirements found in the “Testing and Test Facilities” standard is to ensure employers are identifying these high-voltage and high-power source hazards and effectively controlling them for worker safety.
Testing involving continuous measurements (e.g., routine metering, relaying) and normal line work (e.g., phasing-out testing and testing for no-voltage conditions) is not included within these OSHA requirements as “specialty testing.”
Safe Work Practices
OSHA requires employers to establish and enforce safe work practices for employee protection from electrical testing hazards. At a minimum, work practices must include test area safeguarding, safe grounding, precautions for the use of measuring and control circuits, and periodic safety checks of field test areas. This article identifies some requirements, but it is critical for organizations to fully review the OSHA standard to identify all electrical testing requirements.
Employees must be trained in safe work practices upon initial assignment to test areas; as new technology, new types of equipment and procedural changes are introduced; and when employees have not performed tests within one year of training. Employers are required to complete work practice reviews and update employees as necessary to ensure safe work performance.
Test Area Safeguarding
Test areas are required to be safeguarded to control access to test equipment and apparatus that could become energized. A combination of guards and barriers or barricades can provide safeguarding protection. It’s important to reference the definitions found in OSHA 1910.269(x) or 1926.968 to help ensure an understanding of how to accomplish safeguarding requirements utilizing these methods.
OSHA requires permanent test areas to be guarded with walls, fences or other barriers designed to keep out workers. Field or temporary test sites are required to be safeguarded by using at least one of the following methods to keep out workers without authorization: distinctively colored safety tape waist high with safety signs; an attached barrier or barricade that limits access to the test area; or one or more test observers stationed so that they can monitor the entire area.
According to OSHA, failing to remove temporary safeguarding when it is not required can severely compromise its effectiveness. An example cited references leaving barriers in place for a week when workers perform specialty testing only an hour or two per day; this can result in disregard for the barrier. Employers must develop processes to conduct frequent safety checks to ensure the safeguarding’s effectiveness.
Safe Grounding Practices
Employers are required to establish and implement safe grounding practices for test areas. Grounding practices include ensuring all conductive parts accessible to the test operator are maintained at ground potential while the equipment is operating at high voltage. Ungrounded terminals of test equipment or apparatus under test must be treated as energized until tests have been performed to determine they are de-energized.
Visible grounds must be applied to high-voltage circuits or apparatus under test after they are de-energized and before work is performed. Visible grounds can be applied automatically, or they can be applied manually using a properly insulated tool. Common ground connections are required to be solidly connected to the test equipment and the apparatus under test.
Other requirements include providing an isolated ground-return conductor system designed to prevent the intentional passage of current from occurring in the ground grid or in the earth, and protecting workers – via bonding, insulation or isolation – from hazardous step and touch potentials with respect to vehicles, instrument panels and other conductive parts. According to OSHA, employers must always consider the possibility of voltage gradients developing in the earth during impulse, short-circuit, inrush or oscillatory conditions. Examples of acceptable protection from step and touch potentials include suitable electrical protective equipment and removing workers from areas that expose them to hazardous differences of electrical potential.
Measuring and Control Circuits
The measuring and control circuits portion of the standard includes requirements for control wiring, meters and other instruments, and routing temporary wiring. Additionally, OSHA requires a test observer to be present in the area during testing. The observer must be capable of immediately de-energizing test circuits for safety purposes.
Safety Checks
Safety checks are required at the beginning of each series of tests. The operator responsible for testing must verify the following conditions before testing starts:
- Barriers and safeguards are in workable condition and placed properly to isolate hazardous areas.
- System test status signals, if used, are in operable condition.
- Clearly marked test-power disconnects are readily available in case of an emergency.
- Ground connections are clearly identifiable.
- Personal protective equipment is provided and used as required.
- Proper separation exists between signal, ground and power cables.
Summary
High-voltage and high-current tests performed on circuits and apparatus have unique electrical hazards that require fully developed safe work practices. Organizations have a responsibility to ensure that workers can identify these unique hazards and to implement appropriate safe work practices for their safety. Unfortunately, fatalities and serious injuries have occurred during electrical testing protocols, which emphasizes the importance of a well-planned and fully implemented process to protect workers.
About the Authors: Pam Tompkins, CUSP, CSP, is president and CEO of SET Solutions LLC. She is a 40-year veteran of the electric utility industry, a founding member of the Utility Safety & Ops Leadership Network and past chair of the USOLN executive board. Tompkins worked in the utility industry for over 20 years and has provided electric power safety consulting for the last 20-plus years. An OSHA-authorized instructor, she has supported utilities, contractors and other organizations operating electric power systems in designing and maintaining safety improvement methods and strategies for organizational excellence.
Matt Edmonds, CUSP, CIT, CHST, is vice president of SET Solutions LLC. A published author with over 15 years of safety management experience, he also is an OSHA-authorized instructor for general industry and construction standards. Edmonds provides specialty safety management services for electric power organizations throughout the U.S. He has been instrumental in the development of training courses designed for electric power organizations, including OSHA 10- and 30-hour courses and SET Solutions’ popular OSHA Electric Power Standards Simplified series.
About OSHA Electric Power Standards – Simplified: Topics in this series are derived from SET Solutions’ popular OSHA electric power course offered through the Incident Prevention Institute (https://ip-institute.com). The course is designed to help learners identify standard requirements and to offer practical ways to apply the standards.
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