TECHNICAL TOPICS UNIVERSITY. General Electrical Safety BEST PRACTICES

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1 UNIVERSITY TECHNICAL TOPICS BEST PRACTICES General Electrical Safety Abstract Electrical systems by nature are considered extremely dangerous to most human beings as these systems operate under conditions that are not seen, touched, or felt unless it is by accident. The consequences of these accidents are sometimes catastrophic or fatal. Electricity is not a product that comes bottled and ready for use; it must be designed, installed, and maintained in a manner that makes it safe for human consumption or general use. The installations, maintenance, and inspections of electrical equipment is required by qualified personnel. Sometimes these tasks must be completed on live equipment due to the fact that many buildings and institutions require power to be on at all times. In the building consulting industry, we are often required to enter buildings that have been damaged by any number of natural or human causations and it is imperative to understand the factors involved in remaining safe in these conditions. Introduction This white paper is intended to cover general electrical safety information in relation to understanding electrical systems and best practices in being safe around electrical equipment. This is not an in-depth study of all requirements for electrical safety procedures and practices, but more of a general introduction in being safe around electrical systems. For more information on safety concerns and issues related to electricity overall, we recommend the Electrical Safety Handbook as an excellent resource. The items for discussion relative to electrical safety will include the following topics: Electrical Dangers AC and DC Power Voltage Levels Personal Protective Equipment Understanding Electrical Circuits and Safety Electrical Dangers The International Safety Symbol for Caution Risk of Electrical Shock is illustrated here. Its meaning to anybody who encounters it is ELECTRICAL VOLTAGES ARE PRESENT that are capable of death to a human being.

2 GENERAL ELECTRICAL SAFETY Examples of Protective Strategies in PPE Photovoltaic (Solar) Panels Windmill Farm (Wind) Typical power systems within a building will involve AC systems from a utility source, while some types of buildings will have renewable or green energy sources from PV modules (solar), wind generators, and steam generators.

3 GENERAL ELECTRICAL SAFETY 3 Left: Battery Banks for UPS Right: Rotational Mass Armature for CPS Examples of Engine Generator Emergency Backup Power Plants

4 GENERAL ELECTRICAL SAFETY 4 Power RESIDENTIAL/ COMMERCIAL SYSTEM TYPE Lighting Small Appliance Large Appliance Heating Motors VOLTAGE Fig. 1 Residential/Commercial Voltage Power Matrix

5 GENERAL ELECTRICAL SAFETY 5 Power Lighting INDUSTRIAL SYSTEM TYPE Small Appliance Large Appliance Heating Motors VOLTAGE Fig. Industrial Voltage Power Matrix

6 GENERAL ELECTRICAL SAFETY 6 Top left: Minimum Arc Rating of 4 Cal. Coverall Left: 8 Cal jacket and overalls. Below top: Full Flash suits are rate at 5 CAL and 40 CAL. Below bottom: Four Levels of Arc Fault rated clothing- 4 Cal through 40 Cal.

7 GENERAL ELECTRICAL SAFETY 7 Hazard Risk Categories CATEGORY 1 4 cal/cm Arc-Rated Clothing, Minimum Arc Rating of 4 cal/cm Arc-rated long sleeve shirt and pants or arc-rated coverall Arc-rated face shield or arc flash suit Arc-rated jacket, parka, rainwear, or hard hat liner (AN) Hard hat Safety glasses or safety goggles (SR) Hearing protection (ear canal inserts) Heavy duty leather gloves and leather footwear (AN) CATEGORY 8 cal/cm CATEGORY 3 5 cal/cm CATEGORY 4 40 cal/cm Arc-Rated Clothing, Minimum Arc Rating of 8 cal/cm Arc-rated long sleeve shirt and pants or arc-rated coverall Arc-rated flash suit or arc-rated face shield and arc-rated balaclava Arc-rated jacket, parka, rainwear, or hard hat liner (AN) Hard hat Safety glasses or safety goggles (SR) Hearing protection (ear canal inserts) Heavy duty leather gloves and leather footwear (AN) Arc-Rated Clothing Selected So That the System Arc Rating Meets Required Minimum Arc Rating of 5 cal/cm Arc-rated long sleeve shirt (AR) and arc-rated pants (AR) Arc-rated coverall (AR) and arc-rated flash suit jacket (AR) Arc-rated arc flash suit pants (AR) and arc-rated flash suit hood Arc-rated gloves, arc-rated jacket, parka, rainwear, or hard hat liner (AN) Hard hat, safety glasses or safety goggles (SR) Hearing protection (ear canal inserts) Leather footwear (AN) Arc-Reted Clothing Selected So That the System Arc Rating Meets Required Minimum Arc Rating of 40 cal/cm Arc-rated long sleeve shirt (AR) and arc-rated pants (AR) Arc-rated coverall (AR) and arc-rated flash suit jacket (AR) Arc-rated arc flash suit pants (AR) and arc-rated flash suit hood Arc-rated gloves, arc-rated jacket, parka, rainwear, or hard hat liner (AN) Hard hat, safety glasses or safety goggles (SR) Hearing protection (ear canal inserts) Leather footwear (AN) Examples of leather and voltage rated rubber glove inserts

8 GENERAL ELECTRICAL SAFETY 8 Voltage ratings listed below based on ASTM test standards and specifications.

9 GENERAL ELECTRICAL SAFETY 9 1. 'B' Phase Power Feeder Conductor. 'A' Phase Power Feeder Conductor 3. Neutral Feeder Conductor 4. Ground Bus Bar 5. Branch Circuit Neutral Bus Bar 6. Branch Circuit Neutral Bus Bar 7. Branch Circuit Neutral Bus Bar 8. Branch Power Circuit Breakers 9. Power Bus Bar The left breakers are odd numbered The right breakers are even numbered

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11 GENERAL ELECTRICAL SAFETY 11 If you have questions or would like further information, please contact: Paul Christoferson, Director, at or This publication is for educational and general information purposes only. It may contain errors and is provided as is. It is not intended as specific advice, legal or otherwise. Opinions and views are not necessarily those of J.S. Held or its affiliates and it should not be presumed that J.S. Held subscribes to any particular method, interpretation or analysis merely because it appears in this publication. We disclaim any representation and/or warranty regarding the accuracy, timeliness, quality, or applicability of any of the contents. You should not act, or fail to act, in reliance on this publication and we disclaim all liability in respect to such actions or failure to act. We assume no responsibility for information contained in this publication and disclaim all liability and damages in respect to such information. This publication is not a substitute for competent legal advice. The content herein may be updated or otherwise modified without notice.