Personnel Protection

What is a Special Purpose GFCI?

A Special Purpose GFCI is a personnel protection device designed to meet the requirements defined by UL 943C. This standard outlines GFCI classes specifically designed for use in industrial facilities. Class C GFCIs are intended to be used on three-phase systems where the line-to-line voltage is 480 V or less with a trip level of 20 mA, while Class D GFCIs are intended to be used on 600 V systems.

Commercial kitchens now have a Class A GFCI for 208 V equipment up to 100 A; for industrial applications where Class A GFCIs cannot be applied, utilize Class C & D Special-Purpose GFCI models with UL 943C Listing.

Municipal Water Utility Company Protects Workers From Shock Hazards (Case Study)

A municipal water utility company that supplies water to more than three million residents wanted to protect its workers from shock hazards. The facility has two tanks the size of Olympic swimming pools. Once or twice a year, the tanks must be manually cleaned and workers enter while water is still present and the 600 V submersible pumps are running. The solution was the Littelfuse Industrial Shock Block SB6100 EGFPD. The utility company installed the EGFPDs in the motor control centers that supply power to each pump. The EGFPD is an industrial ground-fault circuit interrupter. If a device senses a ground fault above the trip setting, it will open the circuit very quickly to protect workers from shock.

Brick Manufacturer Protects Workers From Electrocution While Using Wet Saws (Case Study)

A brick manufacturing plant in the Western United States processes clay into bricks and other building materials for residential and commercial projects. Part of this process involves hand-operated wet saws that operate at 480 V.The company wanted to make sure operators were safe from electrical ground faults. The plant electrician discussed his concerns with a Littelfuse distributor in Salt Lake City, Utah, whose representative suggested the use of an equipment ground-fault protection device (EGFPD) from Littelfuse. The Industrial Shock Block SB6100 EGFPD was installed between the motor control center and the face-cut saws on a manufacturing line built in the 80’s. It took a little experimentation to determine that 30 mA was the lowest setting that prevented nuisance tripping. If the device senses a ground fault at or above that threshold, it opens the circuit within 20 ms – fast enough to prevent worker injury or death from dangerous electric shock.

Large Solution Mining Company Protects Employees From Electric Shock Near Pumping Station (Case Study)

Solution mining requires a constant supply of water. A large solution mining company has pump stations located near the water supply to supply water for processing. The water needs to be filtered before it is pumped to the mine, so there is a filter screening the water intake. Even though a second filter is installed inside the pumping station, rocks, sand and debris still get into the station. Typically once a year, an employee must clean the debris out of the sump with the help of a submersible pump. Having a submersible pump running while the employee is cleaning puts them at risk of electrical shock. The Industrial Shock Block SB6100 EGFPD was the solution. They mounted the EGFPD on the wall inside the pumping station. The enclosed-version Industrial Shock Block is well suited for the wall-mount installation used in this application. Now when a worker goes into the pumping station to clean the sump, they will be protected by the Industrial Shock Block.