High Voltage Safe Work Practices – Electrical Safety

It is common for a slight hissing sound to occur when high-voltage breakers or switches are connected to an energized source. This phenomenon is typically associated with the flow of electrical current and is considered a normal part of the operation. It should not be a cause for immediate concern or a reason to halt the operation. Instead, the operation should continue until the breaker or switch is securely and fully engaged in its position. This ensures proper electrical connection and functionality.

High Voltage Safe Work Practices

1. Operating High-Voltage Circuit Breakers, Contactors, and Switches – Verification of Isolation

Operating the isolation mechanism of high-voltage circuit breakers, contactors, and switches requires a meticulous verification process to ensure the safe isolation or connection of the energy source. The following guidelines outline the verification steps, and the appropriate methods for different equipment designs:

1. Indicating Lights:
2. Visual Inspection:
3. Voltmeter:
4. Caution for Equipment with Cubicle Doors:
5. Addressing Verification Challenges:
6. Additional Considerations for HV Motors or Equipment:
7. These verification and isolation procedures are critical to ensuring the safety of personnel working with high-voltage equipment and preventing accidents or electrical hazards.
8. When it becomes necessary for an individual to stay within an electrical room to oversee the instrumentation during the startup of equipment, it is imperative to adhere to specific safety precautions:
9. Personal Protective Equipment (PPE):
10. Access Door and Panel Closure:
11. Limited Personnel Presence:
12. Alternative Monitoring Method:
13. By following these precautions, the safety of personnel can be assured during equipment startup, and the potential hazards associated with high-voltage equipment can be mitigated effectively.
14. The operation of high-voltage motors in areas containing flammable gases carries inherent risks, as there is a potential for ignition if these motors are started in the presence of such gases. To prevent accidents and ensure safety, plant personnel must adhere to specific safety measures when dealing with high-voltage motors in areas with flammable gas installations.
15. These precautions are outlined in Appendix B and are designed to mitigate the associated risks and hazards effectively. Personnel should refer to Appendix B for detailed guidance on safe practices and procedures for starting high-voltage motors in these environments. This proactive approach helps safeguard both personnel and the equipment from potential dangers related to flammable gas atmospheres.
16. Handling and operating protective relays require strict adherence to safety protocols to minimize the risks associated with energized circuits. The following guidelines are essential to ensure the safety of personnel and equipment:
17. Withdrawal of Protective Devices:

• It is strictly prohibited to withdraw protective devices from their cases while the circuit is energized (breaker/contactor closed). Any exceptions to this rule must be explicitly approved by Electrical Engineering management or their authorized representative.

2. Operation or Interrogation from Faceplate:
3. Communication with Relays:
4. These stringent safety measures are essential to prevent accidents, ensure proper equipment operation, and protect the well-being of personnel working with protective relays. Compliance with these guidelines is paramount for maintaining a safe working environment.
5. Utilizing temporary electric power supplies, such as generators, batteries, or customer feeds, to connect to a permanent plant electrical system for temporary power requirements demands strict adherence to safety measures. These precautions are essential to prevent any risks associated with back-feeding electrical equipment that must remain de-energized during maintenance outages or upgrades. Below are the key safety procedures to be followed:
6. Implement Physical Breaks:

• To ensure isolation and prevent back-feeding, create a physical break in the electrical supply system. This can be achieved through actions such as:
  • Withdrawing a withdrawable circuit breaker
  • Removing bus links in a bus duct
  • Removing fuses in a fused switch
  • Removing cable terminations, etc.
• Opening a non-withdrawable device, like a disconnect switch or molded-case breaker, is acceptable for this purpose as long as the device can be locked in the open position and is approved by Electrical Engineering.

2. Ground De-Energized Bus or Section:
3. Pre-work Review:
4. Management of Change (MOC):
5. Restoration Process:
6. Safety Work Permits:
7. Scope Changes:
8. These stringent safety measures are crucial to ensure the safety of personnel and the integrity of the electrical systems when working with temporary electric power supplies. Adherence to these protocols is fundamental in maintaining a secure work environment.
9. Working with batteries and battery-charging installations requires strict adherence to safety protocols to prevent accidents and ensure the well-being of personnel. Here are the key safety measures:
10. Wet-Cell Battery Types:

• Personal Protective Equipment (PPE): When cleaning batteries or handling battery fluids, the PPE specified in Appendix A must be worn. Additionally, chemical gloves and an apron are required for these tasks. For all other battery work, the PPE from Appendix A and a chemical apron are mandatory.
• No Open Flames or Smoking: Prohibit open flames or smoking in battery areas, as hydrogen gas is vented during charging, posing an explosion risk.
• Warning Signs: Avoid using metal warning signs above battery charging installations. Instead, utilize plastic signs or labels.
• Eyewash Station: Battery charging areas where maintenance and servicing occur (excluding installations solely for charging) must have a 15-minute eyewash station installed nearby. If the charging installation is located in electrical rooms, the eyewash should be a self-contained (not plumbed) model. It must be designed to contain used water in a reservoir or prevent it from draining onto the floor.

2. Sealed Battery Types

• PPE: When cleaning or testing sealed batteries, the PPE outlined in Appendix A should be worn. An eyewash station is not required for this battery type.

Adhering to these safety guidelines is crucial to protect personnel when working with batteries and battery-charging installations and to mitigate potential hazards associated with these tasks.

7. Housekeeping and Cleaning Solvent Restrictions – Safety Guidelines

Maintaining proper housekeeping and using approved cleaning solvents are essential for electrical safety. Here are the key guidelines:

Housekeeping Restrictions

• Permissible Housekeeping Activities: Routine housekeeping activities like floor cleaning can be carried out without the need for a Safety Work Permit.
• Authorization Required: For housekeeping activities other than routine cleaning, a Safety Work Permit is mandatory, and appropriate precautions must be taken.
• Avoid Electrically-Conductive Materials: Electrically-conductive cleaning materials, including steel wool, silicon carbide, and conductive liquid solutions such as water, should not be used, as they can pose electrical hazards.

Approved Cleaning Solvents

• Use Approved Solvents: Only cleaning solvents that have been approved by Electrical Engineering should be used when cleaning or working around electrical equipment.

Adhering to these guidelines is crucial to prevent electrical hazards and ensure the safety of personnel when performing housekeeping and cleaning tasks in areas with electrical equipment.