Bakery Technical Briefs
Arc Flash General Overview
In the last several years, Arc Flash hazards and Arc Flash Safety are topics that have come much further to the forefront due to changes in various codes, including the National Electrical Code (NEC) and the publishing of “Standard for Electrical Safety in the Workplace” (NFPA 70E).
Unfortunately, while these codes and standards exist, understanding of this subject has been slow in coming, especially to smaller industries. This document is designed to be a VERY brief and VERY general overview to give the reader a basic starting place to help understand these topics, how it can affect them, and the things they are expected to do by various codes and safety organizations, including OSHA.
Why the Focus on Arc Flash?
Arc flash incidents in the U.S. cause more than 30,000 injuries every year with about 3% of these resulting in death. Arc flash is a growing source of concern for manufacturers and other employers, and OSHA has begun citing companies for arc flash violations. Arc Flash is the result of a rapid release of energy due to an arcing fault between a phase bus bar and another phase bus bar, neutral or a ground. Arc flash can be caused by deteriorating insulation, corroded or improperly maintained electrical equipment, or simply dropping tools while working on energized equipment. It most often occurs when removing panels, opening electrical doors, racking or servicing breakers, or during troubleshooting operations.
Safe-DD® Externally Mounted Dual Disconnect
The Banner-Day externally mounted Safe-DD® dual disconnect is a compact panel containing two fused disconnects (primary and lighting), a control transformer and appropriately sized fusing. The main disconnect is responsible for feeding the primary power to the main control panel. The secondary lighting disconnect, wired in parallel to the main disconnect, provides power to the lighting circuit. This parallel wiring is designed specifically so the main power may be locked out separately, while maintaining an active lighting circuit. The lighting circuit is intended to power various light sources (both inside the main panel and on the machine) and allow the PLC and HMI devices to remain active. This capability of the Safe-DD® can be especially useful during machine installation/startup and when modifications are made as it allows the machine to be mechanically/electrically worked on in a safe manner while still allowing the debug of the PLC/HMI software.
NEC Control Panel Labeling Requirements and Impact on the Baker
The National Electrical Code (NEC) is a national standard authored and published by the National Fire Protection Agency (NFPA 70). This standard is adopted as regulation in all 50 states and is the benchmark for safe electrical design, installation, and inspection to protect people and property from electrical hazards.