Grounding is a term and practice that all electrical workers should be familiar with. Ground faults are said to be the most common type of electrical fault and are responsible for 70% to 80% of all faults in power systems. Additionally, roughly 14% of electrical fatalities can be attributed to improper or inadequate grounding. These hazards are also one of the leading causes of all electrical injuries. It is critical for workers and employers to know the dangers associated with improper and insufficient grounding.

According to NFPA 70E, Standard for Electrical Safety in the Workplace, grounding is defined as “connecting to ground or to a conductive body that extends the ground connection.” Electrical workers may assume it simply involves connecting a grounding conductor to the earth. However, it is often much more complicated.

Initially, there must be an effective ground-fault current path established to make an electrical system safe. This means there is a low-impedance, electrically conductive path to enable the overcurrent protective device to operate. The path must be able to safely carry the maximum anticipated ground-fault current within an electrical wiring system where a ground fault may occur. The ground or earth alone is not considered a sufficient enough ground-fault current path.

According to Dean Austin, senior electrical specialist, writing for the NFPA blog, grounding is “the very foundation of a building or structure’s electrical system. According to 250.20(B) of the 2020 NEC alternating-­current (AC) systems of 50 volts to 1,000 volts must be grounded which means referenced to earth. This is accomplished through a properly installed grounding electrode system. Having a strong grounding electrode system stabilizes voltage and helps to clear ground faults. The 2020 NEC, Section 250.50 gives the outline of a grounding electrode system and section 250.52 lists the approved grounding electrodes.” 

To achieve grounded systems in buildings or other structures, efficient grounding electrodes may include metal underground water pipes, metal in-ground support structures, concrete-encased electrodes, footer or Ufer grounds, and ground rings. 

GFCIs rule

There are several measures employers and workers can take to mitigate hazards associated with ground faults and insufficient grounding. First, it is imperative to verify all equipment is properly grounded prior to use. Work areas should be dry and ground-fault circuit interrupters (GFCIs) should always be used in potential wet areas. 

It is important to provide an effective ground path to provide a safe route for electricity to travel during a fault and keep it from passing through a person. When grounding is insufficient, any worker touching a faulty tool or piece of equipment may receive a severe electrical shock or electrocution. 

As a result, it is critical to ground all power supply systems, electrical circuits and equipment to provide a safe path for fault current. Electrical tools and cords should also be examined for defects such as frayed wires, cracked casings or missing ground prongs. 

Ways to stay safe

If equipment is defective, it must be immediately taken out of service and tagged for repair. Workers should never attempt to bypass grounding by removing the ground prong from a plug or extension cord. Additionally, double-insulated tools should be used whenever possible. Installation and use of GFCIs on all 15A and 20A, 120V receptacles is also recommended. They should be regularly tested in accordance with manufacturer’s instructions. 

However, it is important to understand GFCI limitations. They protect against ground faults but will not safeguard against contact hazards or touching two “hot” wires together at the same time. 

As mentioned earlier, work areas must be kept as dry as possible. Insulation mats or other protective measures should be used when working in or near wet areas. Workers must be aware of electrical hazards, dampness, moisture, exposed wires or overheating equipment in effort to avoid an incident.

Finally, Austin said, “Failure to establish an effective ground-fault current path through proper grounding and bonding may prevent OCPDs from working properly and therefore not effectively clearing a ground-fault, which could result in a shock, electrocution, or arc-flash incident. By creating the effective ground-fault current path you’ll not only be doing the job correctly, but you’ll be keeping yourself and others safe to boot.”

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