First UL Listed Industrial GFCI from Littelfuse Protects Workers

CHICAGO, May 22, 2013 – Littelfuse announced the SB6100 Series Industrial Shock-Block™, the first and only ground fault circuit interrupter (GFCI) device to meet UL 943C Class C and Class D requirements. Until now, GFCI devices have not been practical in industrial settings. Thanks to higher trip level standards and advanced filtering technology, industrial workers can finally be protected against dangerous electric shock.

GFCI devices operate by sensing a ground fault and opening the circuit very quickly. However, the GFCI devices used in residential and commercial applications are too sensitive to operate in industrial applications without nuisance tripping. That's why UL 943C Class C and Class D standards cover GFCI devices for use with systems up to 600V that have leakage current higher than the 6 mA trip level of Class A GFCI devices.

Target applications of industrial GFCI devices include electrical cabinets supplying power to pumps, paint booths, washers, mixers, welding equipment, and any high voltage machinery subject to wet conditions or wash down cleaning. In addition, industrial GFCI devices can be mounted in movable enclosures for flexible use.

Electrical Shock Is a Leading Hazard

According to Tony Locker, P.E., product manager for Littelfuse Protection Relays, “the adoption of industrial GFCI devices is expected to grow because electric shock remains a major cause of workplace injury”. A recent IEEE white paper points out that although arc flash hazards are rightfully receiving a lot of attention, shock hazards should not be ignored as they are the cause of nearly all electrical fatalities and account for 61% of non-fatal electrical injuries.

Exclusive Features Enabled the Littelfuse Shock-Block™ GFCI to Pass Rigorous UL Tests

Industrial GFCI devices have a set 20mA trip level, which is set by the UL943 standard. Equipment ground fault protection devices (EGFPD) have the same functionality as a GFCI but offer adjustable trip settings from 6mA to 30mA for added flexibility. Both models have voltage ratings range from 208 to 600 V and are rated at 100 A.

To pass rigorous UL test requirements, Littelfuse added several safety features which are not found on standard Class A GFCI devices including:

• Monitoring the integrity of the ground wire to ensure a return path for leakage current. If the wire is broken or becomes loose, the SB6100 device will signal an alarm and interrupt power. Without this feature, workers might wrongly assume they are protected even when the ground connection has failed.

• Even though UL requires a minimum short circuit current rating of 5,000 A, the SB6100 device is tested up to 50,000 A. This eliminates the need for adding external fuses for short-circuit protection.

• Performance requirements (Inverse time trip curve) specific for the application

In addition, the SB6100 Series goes beyond the UL standards by including built-in overcurrent protection supplied by Littelfuse Class T fuses. Because fusing is included, installation is easy and there are no extra costs. The interface has LEDs that indicate power and operational status, percentage leakage current, trip status, incorrect supply connection, and ground wire integrity status.

The new Littelfuse GFCI is available as an open-chassis unit that is UL-recognized for installation by an OEM, or as an enclosed unit having a NEMA-4X UL-listed enclosure.

For More Information

The SB6100 Series GFCI is available immediately from stock. For more information, visit www.littelfuse.com/isb. For more information on Littelfuse Protection Relay Products, or any of Littelfuse's circuit protection devices, visit the Littelfuse protection relay website at www.littelfuse.com/relayscontrols or call 1-800-832-3873.

About Littelfuse

Founded in 1927, Littelfuse, Inc., the worldwide leader in circuit protection, offers the industry's broadest and deepest portfolio of circuit protection products and solutions.  Littelfuse devices protect products in virtually every market that uses electrical energy, from consumer electronics to automobiles to industrial equipment.  In addition to its Chicago, Illinois, world headquarters, Littelfuse has more than 30 sales, distribution, manufacturing and engineering facilities in the Americas, Europe and Asia.  Technologies offered by Littelfuse include Fuses; Gas Discharge Tubes (GDTs); Positive Temperature Coefficient Devices (PTCs); PulseGuard® ESD Suppressors; SIDACtor® Devices; Silicon Protection Arrays (SPA® Diode Arrays); Switching Thyristors; TVS Diodes and Varistors.  The company also offers a comprehensive line of highly reliable Electromechanical and Electronic Switch and Control Devices for commercial and specialty vehicles and Sensors for automobile safety systems, as well as Protection Relays and underground Power Distribution Centers for safe control and distribution of electricity.

For more information, please visit the Littelfuse website: littelfuse.com.

1IEEE White Paper, “The Effects of System Grounding, Bus Insulation and Probability on Arc Flash Hazard Reduction”-the Missing Links”, by Nelson, Billman, and Bowen, 2012.