This article is about Electrical Safety, electrical safe work practices, procedure, how to maintain safety during electrical works and installation, overhead power lines safe work practice and osha electrical safety related work practices.
Electrical Safe Work Practices and Procedure
1. Electrical Safety Awareness and Aptitude Training (E-SAT)
To ensure the safety and competence of personnel working with specific electrical equipment, only individuals who possess the necessary training and understanding of the equipment in question will be authorized to work on or operate it. These trained individuals must have the requisite knowledge and skills to conduct electrical work or operations safely.
In cases where electrical equipment supplier representatives, power utility personnel, or electrical service personnel are engaged in work on equipment, they may work independently provided they have thoroughly reviewed and signed the Summary of Safe Work Practices document for electrical work. Additionally, they must undergo appropriate site induction conducted by the relevant technical personnel.
If an individual is uncertain about their ability to perform a task safely, and this uncertainty arises during a work request, it is imperative to initiate a thorough review of the situation. This review should involve the concerned individual, site management, and Electrical Engineering to ensure that all necessary precautions are taken and that the work is carried out safely and effectively.
2. Safety Work Permits, Lockout/Tagout, Energy Isolation, and High Voltage Electrical Isolation Certificate
Safety Work Permits
For any work conducted on industrial electrical equipment, the issuance of Safety Work Permits is mandatory.
Lockout/Tagout
Before any equipment can be started up, it must undergo a lockout/tagout procedure to ensure it is non-operational and de-energized. This step is crucial for safety.
Energy Isolation
Strict adherence to energy isolation procedures for system isolation is essential to prevent accidents and hazards.
High Voltage Electrical Isolation Certificate
When working on high voltage electrical equipment, it is imperative to obtain a High Voltage Electrical Isolation Certificate (HV EIC) in conjunction with the Safety Work Permit. Generally, an HV EIC is required when there is a potential for exposure or physical contact with high voltage conductors, terminations, or equipment, necessitating the opening, removal, or disassembly of an enclosure or panel. This includes scenarios such as the removal of main motor enclosures for winding inspection or air gap checks.
Instances where an HV EIC is not needed include:
- Mechanical work on equipment like compressors, pumps, or other process equipment that requires the isolation and tagging of a breaker before work begins.
- Maintenance or troubleshooting involving withdrawable electrical devices that have been isolated from the energy source and physically removed from the cubicle. This encompasses circuit breakers, HV contactors, and similar components.
- External visual inspections of electrical equipment, including substations, as well as the withdrawal of transformer oil samples.
- Maintenance or troubleshooting activities related to brush or brushless excitation systems that are not integrated into the main motor enclosure.
These safety measures are vital to protect personnel and ensure the safe execution of electrical work.
3. Work in Hazardous Classified Areas
When it comes to working on or with electrical equipment situated in classified hazardous areas, there are specific precautions that must be diligently followed.
General Requirements:
- All installed equipment, portable tools, and test equipment used in these hazardous areas must possess the necessary certifications for safe operation within that classified area.
Exception Handling:
- In cases where portable tools or test equipment lack the required certifications for the specific hazardous area, the area itself must be tested to determine the presence of flammable gases. Subsequently, a safety work permit must be issued for any work to be conducted in that area.
Additional Precautions:
- Prior to any actions involving the removal of bolted covers, opening of hinged covers to expose conductors or terminals (for tests before touch), or for approved diagnostic testing, a thorough assessment for the presence of flammable gas must be carried out. Subsequently, a safety work permit is required for such work.
Personal Protective Equipment (PPE):
- Personnel involved in these operations are obligated to wear appropriate Personal Protective Equipment (PPE) as outlined in Appendix A. It’s important to note that the hazardous area might necessitate additional PPE based on site-specific requirements.
These stringent measures are imperative to safeguard personnel and ensure the secure execution of tasks in hazardous classified areas.
4. Personal Protective Equipment (PPE)
The safety of personnel working on electrical systems hinges on the correct use of Personal Protective Equipment (PPE) as outlined in Appendix A, tailored to the specific tasks being performed.
Prohibited Conductive Articles:
- Jewelry and clothing items with conductive properties, including but not limited to watchbands, bracelets, rings, keychains, necklaces, metalized aprons, cloth with conductive thread, metal headgear, or unrestrained metal frame glasses, must not be worn when they pose an electrical contact hazard with live parts. These articles should be made nonconductive through insulation, covering, or other appropriate means.
Cell Line Working Zone (CLWZ) Regulations:
- Within a Cell Line Working Zone (CLWZ), personnel are strictly prohibited from wearing any metallic jewelry on the outside of their PPE. This encompasses items like necklaces, watches, rings, bracelets, etc. This is a crucial safety measure considering the potential presence of high magnetic fields in CLWZ, which can lead to inductive heating of metallic jewelry and subsequent thermal burns to personnel.
Additional PPE Requirements:
- Depending on the specific plant requirements, additional PPE may be mandated, especially in environments like clean rooms or food processing facilities. These requirements are in addition to the electrical PPE defined in Appendix A.
1. Posting Single Line Diagrams:
In areas containing electrical distribution equipment, copies of the most recent High and Low Voltage single line diagrams, along with Hazard Risk Category Classification (task table) must be conspicuously posted. These diagrams should also reflect equipment specific to that area. In cases where there’s no designated electrical room or area, single line information should be accessible through incoming equipment or control rooms.
2. Availability of PPE:
Facilities where Qualified Level work is conducted, whether by contractor company personnel or contract workers, must have the appropriate PPE readily available. The facility should determine the quantity of PPE sets required on-site.
3. Safety Glasses:
Safety glasses worn by electrical maintenance and operating personnel should feature polycarbonate lenses or lenses with Ultra-Violet protective coatings, offering superior protection against potentially damaging Ultra-Violet radiation emitted in high-energy electrical arcs.
4. Hearing Protection:
Hearing protection is mandatory and should be worn by personnel working with electrical PPE across all categories.
5. Voltage Rated Gloves:
Voltage rated gloves should be part of a maintenance schedule, subject to dielectric proof testing and visual inspection. These gloves must undergo testing and date-stamping every six months or as dictated by regional or national standards. A local inspection program is essential for quarterly inspections, ensuring in-use gloves have a current proof-test date. Voltage rated gloves should be inspected for damage and proof-test date validity before each use. Additionally, they should be air-tested and inspected prior to every use. Gloves of Class 0 and Class 2 come with matching leather protectors and storage bags. Store these gloves and leather protectors in the bag when not in use and inspect the protectors for damage before each use, replacing them as necessary.
6. Arc Rated PPE and Clothing:
Arc rated PPE and clothing require regular inspections for contaminants such as dirt and grease, as well as tears and other defects before each use. When cleaning arc rated PPE clothing, it’s essential to adhere to the manufacturer’s instructions to maintain protection levels. Any defective equipment should be promptly replaced to ensure personnel safety.
5. Tools and Safety Equipment
Proper tools and safety equipment are important for ensuring the safety of personnel working with electrical systems.
Voltage Rated Tools:
Voltage rated tools, as detailed in Appendix A of this procedure, should be used as prescribed.
Fuse Removal and Insertion:
Removal and insertion of fuses, whether high- or low-voltage, must only be undertaken with approved fuse-pulling tools.
Storage Regulations:
Electrical rooms and electrical control cubicles are not intended for general material storage. They should only house small ladders, special tools, and clothing required for electrical equipment operation.
Restrictions on Metal Items:
In switchyards, electrical rooms, or electrolytic cell areas, metal ladders, metal flashlights, and metal barrier chains are strictly prohibited.
Safety Equipment Storage:
Facilities should provide storage lockers in electrical rooms or other appropriate areas for storing required PPE and electrical tools, such as fuse pullers, voltage-rated tools, and audio-voltage testers. These lockers should be clearly labeled with content information (e.g., inventory list) and marked as “Safety Equipment.” In cases where there’s no specific designated room or area, PPE and electrical equipment can be stored in vehicles or control rooms, provided they are protected from damage.
Cell Line Working Zone (CLWZ):
Within the Cell Line Working Zone (CLWZ), battery-operated tools are permitted. If there’s a need for electrically powered corded hand tools for special purposes, they must be of the double-insulated, ungrounded frame type.
Voltage-Rated Hand Tools:
While working in the CLWZ, cell line personnel must exclusively use voltage-rated hand tools. If a metal tool is necessary for the task, it must have either a non-conductive handle or an insulated handle. Metallic “cheater” or extension handles should never be used on any wrench or tool under any circumstances.
Preventing Bridging:
Tools used in the energized CLWZ must be selected to prevent bridging between surfaces at different electrical potentials.
Magnetic Materials:
Tools and equipment containing magnetic material should be handled with care in energized cell areas due to strong DC magnetic fields.
2. Wire-Pulling Devices (Fish Tapes) for Conduit Systems:
The use of bare metal wire-pulling devices for pulling wire is not allowed. Instead, insulated metal wire-pulling devices, non-metallic wire-pulling devices, or a vacuum and string system are acceptable methods for wire pulling. If insulated metal wire-pulling devices are used, their insulation integrity must be visually inspected before each use.
3. Fire Extinguishers:
Fire extinguishers must be readily accessible inside electrical rooms, positioned as close to the entrance as possible. In cases where there is no building, outdoor extinguishers should be located within easy reach of the equipment but not closer than 3 meters. CO2 fire extinguishers are preferred for use on electrical equipment, specifically for extinguishing minor, localized fires where it is safe to do so. If CO2 proves ineffective for extinguishing such fires, personnel should evacuate the area and initiate site fire emergency procedures. Fire extinguishers in electrical rooms are required to have non-conductive horns. Under no circumstances should personnel enter electrical rooms engulfed in fire or heavy smoke, and instead, they should immediately follow site fire emergency procedures.
4. Proper Illumination:
Adequate illumination is a prerequisite before any work on electrical equipment. If the installed lighting is insufficient to illuminate all necessary areas, additional lighting must be provided. This additional lighting should be securely fixed to prevent tripping or falling hazards.
5. GFCI (Ground Fault Circuit Interrupter)/RCD (Residual Current Device):
For any maintenance, repair, operating, or construction work involving power tools and/or electrical utility equipment, indoors or outdoors, the use of GFCIs/RCDs is mandatory. These devices should conform to local codes, national standards, or country-specific regulations. For permanent or semi-permanent non-industrial electrical equipment located indoors in dry areas, such as computers, PLCs, copiers, fridges, and microwaves, GFCIs may not be necessary unless mandated by local codes, national standards, or country-specific regulations. GFCI/RCD devices with a test feature should be tested before each use.
6. Voltage Testers
Proper use of voltage testers is vital to ensure electrical safety during work.
AC Voltage Testing:
Preferred Device: The preferred tool for verifying the de-energization of an AC circuit before electrical work begins is a non-contact audio and visual voltage tester. Contact-type voltage testers can be used with prior approval from Electrical Engineering. Approved manufacturer and device types must meet Electrical Engineering’s standards. Contact-type testers (e.g., Fluke, Simpson) should not be used on systems with nominal voltage ratings exceeding the tester’s rating. Only testers rated Category III or higher are allowed for contact-type testing. Solenoid-type testers are strictly prohibited, regardless of their rated category.
DC Voltage Testing:
It’s important to note that non-contact voltage testers are not suitable for DC testing. Contact-type testers (e.g., Fluke, Simpson) must not be used on systems with nominal voltage ratings exceeding the tester’s voltage rating.
1. Use of “Hot Sticks” with Audio and/or Visual High-Voltage Testers:
Each tester comes with an insulated extension (Hot Stick) for high-voltage systems within their rating. Hot Sticks should be included in a maintenance program for dielectric proof testing, with testing conducted at least every two years or as frequently as required by local regulations.
2. PPE for Use with Voltage Testers:
When using a voltage tester on electrical equipment or systems, appropriate PPE as specified in Appendix A must always be worn.
3. Storage of Voltage Testers:
Voltage testers are critical safety devices that must be stored in a way that prevents damage to both the tester and the test leads.
4. Using a Voltage Tester:
The correct procedure for testing for the presence of voltage with a voltage tester involves the following steps: a. Ensure that the voltage tester (and leads if applicable) are rated at or higher than the voltage level being tested. Prior to use, inspect the tester and/or leads to verify they are undamaged. b. Test the tester for proper operation on a known energized circuit or approved testing device. c. Test the circuit to be worked on to determine its voltage status (whether it’s energized or de-energized).
7. Use of Diagnostic Test Instruments
When using diagnostic test instruments, such as insulation resistance testers, over/high potential testers, surge testers, and more, safety precautions are paramount.
7.1 Testing Before Touch:
Before utilizing diagnostic test instruments on equipment, devices, or cables, they must be tested to confirm they are de-energized. This practice is commonly known as “test before touch.” During this process, individuals must wear the appropriate PPE as outlined in Appendix A for testing before making physical contact with the equipment.
7.2 PPE Requirements:
When diagnostic test instruments necessitate manual holding of test leads during testing, personnel must wear the necessary PPE. Voltage-rated gloves matching the voltage level of the test instrument are mandatory, regardless of whether the testing involves AC or DC values. If the test leads can be securely fastened to the equipment under examination, PPE is not required for conducting the test, provided that the test instrument manufacturer’s instructions are adhered to.
7.3 Maintaining Safe Working Distance:
To ensure safety, precautions must be taken to maintain a safe working distance from the equipment under examination.
7.4 Opening Equipment Panels and Covers:
It is strictly prohibited to open equipment panels or covers with the intent of exposing energized conductors for the purpose of insulation resistance testing. This practice is unacceptable and poses a significant safety hazard.
Read Also: 8. General Safe Work Practices This is also part of this topic.