Stanford University

Electrical Safety

Whenever electrical power is used, there is a danger of injury through electrical shock.

All electrical equipment should be adequately insulated, grounded, or isolated to prevent bodily contact with any source of dangerous potentials. Under certain conditions, people can be severely injured, even from relatively low voltages coupled with high current.

The primary effects of electrical shock are due to current flowing through the body. Electrical burns occur when all or part of the body completes a circuit, connecting the power source with the ground. Although the resistance of dry, unbroken skin to electric current is relatively high, the amount of current necessary to kill a person is small. Therefore, it is easy to exceed lethal levels of current flow, especially if the skin is broken, wet, or damp with sweat.

If your equipment runs erratically or if you feel an electrical “tingle” when you touch it, stop using the tool, tag it, and have it repaired. Whenever the risk of electrocution is high, wear proper protective clothing: insulated gloves, eye protection, boots, and head gear. If you are not sure what to wear, ask your supervisor or contact EH&S.

General electrical safety is addressed in EHS 2800. Specific electrical hazards and safe practices are to be covered locally by supervisors via safety training on standard operating procedures. The following list provides basic electrical safety rules:

  • Immediately report damaged or malfunctioning items to your supervisor, and take them out of service until repaired by a qualified electrician.
  • Equipment and handheld tools should have three-prong plugs and/or double insulation.
  • Portable electric tools shall not be lifted or lowered by means of the power cord. Use ropes.
  • Use ground fault circuit interrupter (GFCI)-type outlets or portable GFCIs when possible (especially outdoors or in other potentially wet areas).
  • Unplug any tool or equipment that generates heat when not in use.
  • Extension cords cannot be used as permanent wiring (i.e. for longer than 90 days).
  • Do not “daisy chain” extension cords and/or power strips.
  • Prevent damage to the cord and plug. Avoid using nails to secure a cord. Avoid placing cords in walkways or driveways.
  • Only use extension cords rated for the equipment power needs.
  • Avoid overloading electrical outlets.
  • Label all circuit box switches.
  • Leave at least 36” clearance in front of electrical panels.
  • Ensure that no circuits or parts are exposed (e.g. outlet cover plates or electrical panel doors).
  • Never repair or modify electrical wiring unless shop-specific training is provided. For assistance, contact the University’s Electric Shop (x3-1836).
The Electrical Safety Management Plan for Research (ESMPR) is the framework document for safe conduct of research activities involving routine and higher levels of electrical hazards. The goal of the ESMPR is to mitigate the risk of electrical shock and arc flash injuries by providing clear roles and responsibilities and guidance on safety controls. It draws from standards and regulations including NFPA 70E, NFPA 70 (National Electric Code), Cal/OSHA Electrical Safety Orders, California Electric Code, and International Electric Equipment Engineering Codes (IEEE). Please call (650) 723-0448 with any questions.


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