The first step in establishing an electrically safe work environment is knowing what risks and hazards are present. The NFPA 70E “Standard for Electrical Safety in the workplace”® establishes the standards and guidelines for conducting risk assessments and defining the proper level of personal protective equipment (PPE) necessary to protect employees.

Arc Flash Risk Assessments

Systems Interface can help your firm comply with NFPA 70E standards by conducting an Arc Flash Risk Assessment, conducting selective coordination studies, generating Danger and Warning labels for your control panels and making recommendations that may mitigate the arc flash potentials present.

An SKM Power Tools software package (PTW Arc Flash) is used to model a facilities electrical system and perform calculations. Our Power System specialists then analyze this data to look for ways to mitigate arc flash potentials.

          We would welcome the opportunity to work with your plant to conduct Arc Flash Risk Assessment and Time Current Coordination Studies.

The Data contained in the Warning labels includes the Equipment name, date of inspection and both Arc Flash Protection and Shock Protection information.

Arc Flash Protection:

• Arc Flash Boundary in feet and inches
• Incident Energy in Cal/Cm²
• PPE Category Required

Shock Protection:

• Shock Risk in Voltage
• Limited Approach distance in feet and inches
• Restricted Approach in feet and inches
• Glove Class

Time Current Coordination Studies

A protective Device Coordination study provides an organized time-current study of all protective devices from the utility to a device. It will provide a comparison of the time it takes a protective device to operate when certain levels of normal or abnormal current pass through them. The objective of the study is to determine the characteristics, ratings, and settings of all over current protective devices to insure that all devices are being protected.

The figure to the left illustrates the time-current characteristic curve for a typical motor showing the motor, the overload, the motor circuit protector, the MCC main breaker, all the way to the Utility Main Breaker. The horizontal axis represents the current, and the vertical axis represents the time at which the breaker interrupts the circuit.