Electrical Safety

You must follow all recommended safety procedures when servicing and working near energy sources.

MR RAC Reference: 1.100.10, 1.100.20, 1.200.10, 1.200.20; PPE hazard class requirements are found in NFPA 70E (per EHS).
Notice Image
  • danger
  • Electrical Shock
  • The MR system operates at high voltages that will shock or kill you if appropriate safety precautions are not taken. When performing any service in or around an MR system, always make sure you adhere to the following requirements.
  • If any of these requirements are unclear or in conflict, do not begin work or immediately stop work and contact your supervisor, this site safety officer, or your GE Healthcare service representative for guidance.
  • Follow all electrical safety and LOTO procedures in this manual, the MR service documentation, or any other applicable service manual.
  • Refer to the appropriate MR employee health and safety (EHS) or your equivalent employee electrical safety training for general LOTO information.
  • Understand and follow all site-specific electrical safety protocols.
  • After LOTO is applied, always verify the power is removed before starting any work.
  • Always wear appropriate electrical personal protective equipment (PPE).
  • Never defeat any safety interlock.
  • Never scan with covers or other safety interlocks removed.
  • Always ensure all safety interlocks and covers are properly installed before turning over the MR system to the customer.
Notice Image
  • danger
  • Arc Flash
  • The MR system operates at high voltages that can cause arc flash. Arc flash can shock, burn, or kill you. When performing any service in or around a component with the potential for arc flash, always wear appropriate PPE.

4 Arc flash hazard

Arc flash is not a common event but can be extremely dangerous when it occurs. All arc flash precautions must be followed even if you have worked on energized electrical equipment in the past and never encountered arc flash.

Arc flash is a high-energy discharge of highly-conductive plasma.
  • Arc flash PPE is required when working on live electrical components (50 to 480 volts).
    note: Some tasks, such as servicing the Main Disconnect Panel (MDP) or Power Distribution Unit (PDU), are not permitted by GE Healthcare service personnel even if appropriate PPE is worn.
  • Arc flash PPE must be worn inside the flash protection boundary (48 inches [122 cm] minimum).
  • Arc flash PPE is required during the zero-energy verification step when performing LOTO. All electrical circuits must be considered energized with the potential for an arc flash until verification with a voltmeter is completed.
  • The arc flash PPE listed in this chapter is a minimum requirement. Your site may have additional or stricter requirements.
  • Follow all site-specific arc flash safety requirements. Your site may have arc flash labels on components or require a risk assessment before performing tasks with the potential for arc flash.
  • Follow all GE Healthcare EHS (or equivalent) arc flash training.

5 Electrical installation and servicing

  • All MR system electrical work must comply with applicable electrical codes.
  • Electrical service must be completed by qualified service personnel.
  • The Main Disconnect Panel (MDP) and Power Distribution Unit (PDU) must be installed and serviced (including tightening nuts, changing fuses, or replacing batteries) by a licensed or certified electrician with the exception noted below:
    note:

    MR service personnel may perform live electrical calibration, testing, or troubleshooting on a PDU or GE MDP if all of the following conditions are met:

    • Live electrical calibration, testing, or troubleshooting is permitted by local code or regulation.
    • The FE has completed arc flash and LOTO training.
    • The FE is wearing Level 2 arc flash PPE.
    • The FE has the approved calibration, troubleshooting, and test tools.
  • Electrical connection between the PDU and other applicable equipment must be a installed by a licensed or certified electrician.
  • Other electrical connections, calibrations, or testing may be completed by qualified service personnel.
  • All applicable LOTO procedures must be followed when doing electrical service.

6 PPE hazard class levels

  • The following table is for reference only. Some PPE listed below may have specific ratings. Refer to your EHS (or equivalent) training and site requirements for detailed PPE instructions.
  • GE Healthcare provides PPE as an orderable kit.

7 Task PPE requirements for GE Healthcare FE

  • The table below lists the minimum PPE required for MR system electrical tasks performed by GE Healthcare FEs.
  • All tasks may not be listed. Always follow site safety requirements or check with your supervisor if unsure.

8 RF amplifier electrical hazards

The RF amplifier operates at extremely high voltages and current levels.
  • Before working on the ISC, RF amplifiers or any associated circuitry or cabling, make sure proper LOTO is in place and cabinet power cords are disconnected.
  • Always wait at least five minutes for filter capacitors to discharge before performing any service procedure or removing any module covers.
  • Interlock switches are provided on the covers of power supply and amplifier decks. Never defeat the interlock switches to work on energized components. Even if an interlock switch is disengaged, always use a voltmeter to verify circuits are de-energized.
  • Use a voltmeter to verify RF amplifier circuits are de-energized.

9 Specific component LOTO procedures

The following tables contain specific LOTO procedures for removing power to the system and system components. If your system is not listed, refer to the Safety section in your service documentation for appropriate LOTO procedures.