AE 868
Commercial Solar Electric Systems

Electrical Hazards

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Common electrical accidents are classified as:

  • Direct injuries such as electric shocks, burns, or electrocution
  • Indirect injuries, such as traumatic injuries associated with falls after an electrical shock
  • Concussions
  • Eye damage

These injuries can occur when electric current flows through the human body. The injury can become critical depending on the amount of current, the path through the body, and the duration. It is difficult to estimate when current will flow or the severity of the injury that might occur because the resistivity of human skin varies from just under a few ohms to several hundred thousand ohms depending primarily on skin condition and moisture. DC current generated by PV systems can cause continuous arc, and if it travels through a part of the body, it may cause serious burns. Power conditioning units are hazards, as they generate high AC voltage that can cause injuries as well.

This OSHA prevention video (5:41) describes how to prevent deaths and injuries from employees' contact with overhead power lines while using ladders. Find more information on this topic on the OSHA website.

Electrocution/Work Safely with Ladders Near Power Lines. Transcript (opens in new tab)
Credit: OSHA

This OSHA prevention video (3:53) describes how to prevent deaths and injuries from contact with overhead power lines while using cranes. Find more information on this topic on the OSHA website.

Prevent Electrocutions: Work Safely with Cranes near Power Lines. Transcript (opens in new tab)
Credit: OSHA

Recommendations:

According to the OSHA website, Lockout/Tagout (LOTO) refers to "specific practices and procedures to safeguard employees from the unexpected energization or startup of machinery and equipment, or the release of hazardous energy during service or maintenance activities." This can be done by:

  • Lockout AC or DC power source disconnects using appropriate locks.
  • Labeling all deactivated circuits and equipment when they can be energized.

The following video (1:57) offers more information on this subject.

Electrical Panel Repair Results in Electrocution. Transcript (opens in new tab)
Credit: OSHA

Battery Hazards

Any system with batteries forms a potential hazard. Some areas of concern include:

  • Electrical Burns: Shorting the terminals of a typical battery that might be found in a PV system can cause high currents to flow for a few seconds. Severe burns and death can occur even though the voltage is low.
  • Acid Burns: Any battery acid can cause burns if it comes in contact with exposed skin or eyes.
  • Gas Explosion or Fire: Most batteries used in PV systems release gas as a result of the charging process. This gas may be flammable gas and can create a hazard.

Recommendations:

  • Safety gloves and goggles should be worn when dealing with such hazards.
  • Keep all flames and equipment that could create a spark, such as a controller with relays, away from batteries.
  • The battery should be located in a well-ventilated area.