- Safety Corner | February 22, 2013
Recognizing electrocution hazards can be difficult in job sites and especially in areas/facilities that have experienced storm damage. An electrocution is the result of coming in contact with a lethal amount of current. Ground Fault Circuit Interrupters (GFCIs) are really a last line of defense to protect personnel. There are many ways to stay safe.
The acronym GFCI is used quite often and if I were to hazard a guess, I would say that very often it is used incorrectly. It is not only important to use terminology correctly but to also understand the limitations of the various ground fault devices out there to facilitate in their proper application. Here we will take a high-level look at preventing electrocutions as well as those ground fault devices that we rely on so much for protection.
First Line of Defense
We can't lose site of the fact that a GFCI-type device is really your last line of defense for protection against electrocution. There are many ways to avoid coming in contact with energized conductors and equipment. These other methods include the following:
Grounding and Bonding: National Electrical Code (NEC) 2011's Article 250 takes a total of 31 pages to help ensure the grounding and bonding of your system is the best it can be so that equipment-type ground faults have the lowest amount of impedance possible so that they are high enough to be overcurrents and that are cleared by the over-current protective devices in the circuit. Ground faults can be overcurrents if they are high enough to exceed the ratings of the conductors and other equip-ment. In fact, NEC 2011 Article 100’s definition of overcurrent includes ground faults as this document defines an overcurrent as, “Any current in excess of the rated current of equipment or the ampacity of a conductor. It may result from overload, short circuit, or ground fault.” By ensuring an effective ground path, overcurrent protective devices can do their job in clearing these dangerous faults that if left unattended to due to high impedances, could result in fires and even electrocutions.
Distance: Putting distance between yourself andothers and hazardous locations are one sure way to prevent electrocutions. Barriers and guards can help ensure only qualified individuals are in work areas. National Fire Protection Association (NFPA) 70E, “Standard for Electrical Safety in the Workplace,” has provisions for limited approach boundaries and advises that physical or mechanical barriers should be installed no closer than the restricted approach boundaries defined within that document. It’s advisable to use non-conductive barriers, especially where they may come in contact with energized parts. Distance is good for electrical safety and the more you have of it, the better off you are.
Insulation: Insulated hand tools, matting, andother personal protection equipment (PPE) can help prevent electrocution should you or your tool come in contact with energized equipment. Many times we let our tools fall in to disrepair. This could jeopardize the insulation that is there to protect you. You could have hand tools as bad as that depicted in image 1, where the grip insulation has been completely removed from areas of the handles. Electrical tape is not a fix for this problem; replacement is in order. Insulation on tools and similar work equipment will have ratings and should be periodically tested to ensure the integrity of the insulation.
Working De-Energized/Lockout-Tagout: Yetone more way to ensure your team avoids electrocution is to work on de-energized equipment. Proper lock-out tag-out procedures and effective testing techniques should be followed.
UL 943 vs. UL 1053 Devices
We’re talking “people protection” versus “equipment protection” when we sit these two UL standards side by side. A device tested to UL 943, “Ground Fault Circuit Interrupters,” is one that is intended for the protection of personnel. The Scope of UL 943 reads as follows: “This Standard applies to Class A, single-and three-phase, ground-fault circuit-interrupters intended for protection of personnel, for use only in g