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ES&H Manual TITLE: DOCUMENT ID: 1.0 6230 Appendix T1 Determining Equipment Class and Work Modes Purpose The work rules for electronic equipment are dependent on both the equipment Class and the work Mode. Training requirements and the necessity for Work Control Documents are determined by an evaluation of the Class and Mode. The Class, Mode, and minimum work rules are determined based on the information in this Appendix. 2.0 Scope Equipment Classes, Work Modes, and the associated work rules for each Class and Mode are detailed and defined within this appendix along with other general precautions. 3.0 Responsibilities Individuals: Understand the equipment Class, as defined in this Appendix, of the equipment on which they work. Understand the Modes of work as defined in this Appendix. Follow the work rules for the equipment Class and work Mode for all assigned and authorized work. Personnel Assigning Work: Understand the equipment Class as defined in this Appendix, for the equipment. Understand the work Modes as defined in this Appendix. Ensure that workers assigned to electronic equipment work are trained, knowledgeable, and qualified for the work assigned to them. Understand the requirements associated with each equipment Class and work Mode. 4.0 Expectations/Process Steps When work is performed on electronic equipment the equipment Class and the work Mode must be determined prior to doing any work. Work rules based on Class and Mode, are established to mitigate the hazards due to exposure to electrical energy. ISSUING AUTHORITY APPENDIX AUTHOR APPROVAL DATE EFFECTIVE DATE EXPIRATION DATE REV. ESH&Q Division Bill Merz 12/10/08 12/10/08 12/10/11 1 Page 1 of 6 This document is controlled as an on line file. It may be printed but the print copy is not a controlled document. It is the user’s responsibility to ensure that the document is the same revision as the current on line file. This copy was printed on 5/4/2017. ES&H Manual TITLE: DOCUMENT ID: 6230 Appendix T1 Determining Equipment Class and Work Modes 4.1 Hazard Classes The hazards associated with electronic equipment are divided into three Classes: (See Table 1 – Electronic Work Hazard Classes and Restrictions and Chart 1 – Electronic Equipment Hazard Classes) Class 1 – Low Hazard o ≤ 50 Volts, ≤ 50 Amps o > 50 Volts, ≤ 5 mAmps Class 2 – Medium Hazard o ≤ 50 Volts, > 50 Amps – Low voltage, high current o 50 Volts < V ≤ 250 Volts, > 5 mAmps – Medium to high voltage, medium current o > 250 Volts, I ≤ 500 Watts/Volt – Medium to high voltage, medium current o > 50 Volts, >10 Joules Stored Energy – Medium to high stored energy Class 3 – High Hazard o > 250 Volts, I > 500 Watts/Volt – High voltage, high energy 4.2 Work Modes Three work Modes are defined based on the type of work being performed, the extent of exposure of personnel to hazardous electrical energy and the consequent risk of injury. (See Table 1 – Electronic Work Hazard Classes and Restrictions): Mode 1 – Equipment De-energized o All work is conducted with the equipment completely de-energized and in an electrically safe condition. (Locked out in accordance with ES&H Manual Chapter 6110 Lock, Tag, Try (LTT) Policy), and o Any stored energy is dissipated and any required grounding has been applied. Mode 2 – Non-manipulative Diagnostics on Energized Equipment o Troubleshooting, measurements and diagnostics on or near energized conductors. Voltage testing (zero voltage checks) as part of Lock, Tag, and Try when a Voltage Verification Unit is not present. o Protective barriers or covers are removed from energized components for access to equipment for the purpose of making measurements; and/or Personnel Protection Interlocks (on doors or covers) bypassed to allow access to components for measurements during powered operations. ISSUING AUTHORITY APPENDIX AUTHOR APPROVAL DATE EFFECTIVE DATE EXPIRATION DATE REV. ESH&Q Division Bill Merz 12/10/08 12/10/08 12/10/11 1 Page 2 of 6 This document is controlled as an on line file. It may be printed but the print copy is not a controlled document. It is the user’s responsibility to ensure that the document is the same revision as the current on line file. This copy was printed on 5/4/2017. ES&H Manual TITLE: 6230 Appendix T1 Determining Equipment Class and Work Modes DOCUMENT ID: Mode 3 – Manipulative Operations on Energized Equipment o Equipment is energized while circuit configuration is changed o Protective barriers or covers are removed from energized components for access to equipment for the purpose of making circuit alterations; and/or Personnel Protection Interlocks (on doors or covers) bypassed during powered operations to allow access to components for installation, removal, modification or repair of components. 4.3 Special Notes on Equipment Classes: The following considerations and actions can affect the determination of the equipment Class. These are addressed in work planning: In equipment with multiple voltage and/or current capabilities, the equipment Class is determined by the highest voltage/current to which servicing personnel could be exposed during the work. Exposure to the higher Class voltage/current portions of the equipment may be mitigated by the presence of insulating barriers (either original equipment or temporary), or shielding with dielectric properties suitable for the application. o e.g. – fully covered/insulated 120VAC input service to a low voltage electronics chassis may reduce the equipment classification from Class 2 to Class 1. o Temporary barriers must be secured in a manner to prevent accidental dislodging during work and they must be installed and removed under the appropriate Class and Mode work rules for the higher Class hazard. Equipment containing energy storage devices (batteries, capacitors and inductors) that may have more than 10 joules of stored energy must be evaluated carefully in determining hazard classification. 4.4 Other Precautions The specified work practices listed in Table 1 – Electronic Work Hazard Classes and Restrictions are minimum requirements. Managers or supervisors may specify more restrictive procedures. ISSUING AUTHORITY APPENDIX AUTHOR APPROVAL DATE EFFECTIVE DATE EXPIRATION DATE REV. ESH&Q Division Bill Merz 12/10/08 12/10/08 12/10/11 1 Page 3 of 6 This document is controlled as an on line file. It may be printed but the print copy is not a controlled document. It is the user’s responsibility to ensure that the document is the same revision as the current on line file. This copy was printed on 5/4/2017. ES&H Manual TITLE: DOCUMENT ID: 6230 Appendix T1 Determining Equipment Class and Work Modes Table 1 – Electronic Work Hazard Classes and Restrictions Work involving the primary circuit in electronic equipment must conform to the requirements outlined in ES&H Manual Chapter 6220 AC Electrical Equipment Safe Work Policy. Voltage* Current capacity Hazard Remarks Class 1 ** ≤ 50 V ≤ 50 A > 50 V ≤ 5 mA Mode 1 A qualified person may work alone. Mode 2 A qualified person may work alone Mode 3 If exposed voltages are less than 50 volts differential or to ground, a qualified person can work alone. If greater than 50 volts, a qualified worker must be in the presence of another individual who can provide or summon assistance. Any of these Class 2 ** Voltage* Low Current capacity ≤ 50 V > 50 A 50 < V ≤ 250 > 5 mA Hazard High voltage, very low current Remarks Low voltage, high current Medium > 250 V Low voltage, low power, low to medium current I ≤ 500 watts/V Medium to high voltage and medium/high current high voltage, medium current >50 volts, > 10 Joules Medium to high energy stored Mode 1 A qualified person may work alone. Mode 2 At least two qualified persons are required. They must be in continuous sight and sound communication. A work control document approved by a cognizant AD and specifying PPE and shock/arc flash boundaries is required. Mode 3 A work control document (e.g., SOP or OSP) must be used to describe how the work is to be accomplished safely. An EEWP approved by the Laboratory Director justifying why the work must be performed energized must be completed. The work supervisor must sign the procedure and provide direct supervision for the work. Class 3 ** Voltage* >250 V Current capacity Hazard I > 500 watts/V High Remarks DANGER – high voltage , high current Mode 1 At least two qualified persons must be present until it has been clearly verified that the equipment has been deenergized. Then, one qualified person may work alone. Mode 2 At least two qualified persons are required. They must be in continuous sight and sound communication. Implied approval and general supervision must exist. A work control document approved by the AD and specifying PPE and shock/arc flash boundaries is required. Mode 3 A work control document (e.g., SOP or OSP) must be used to describe how the work is to be accomplished safely. An Electrical Safety Work Permit justifying why the work must be performed energized must be completed. The work procedure and permit must be approved by the Laboratory Director for each occurrence of the work. The work supervisor must sign the procedure and provide direct supervision for the work. * Voltage is line-to-ground or line-to-line, whichever is higher. ISSUING AUTHORITY APPENDIX AUTHOR APPROVAL DATE EFFECTIVE DATE EXPIRATION DATE REV. ESH&Q Division Bill Merz 12/10/08 12/10/08 12/10/11 1 Page 4 of 6 This document is controlled as an on line file. It may be printed but the print copy is not a controlled document. It is the user’s responsibility to ensure that the document is the same revision as the current on line file. This copy was printed on 5/4/2017. ES&H Manual TITLE: DOCUMENT ID: 6230 Appendix T1 Determining Equipment Class and Work Modes ** Class is determined by the highest voltage or current to which personnel may be exposed during servicing operations Chart 1 – Electronic Equipment Hazard Classes 5.0 References NFPA 70E - Standards for Electrical Safety in the Workplace NFPA 70 - National Electric Code OSHA Regulation 29 CFR 1910 Subpart S and 29 CFR 1926 Subpart K DOE Electrical Safety Guidelines Handbook ISSUING AUTHORITY APPENDIX AUTHOR APPROVAL DATE EFFECTIVE DATE EXPIRATION DATE REV. ESH&Q Division Bill Merz 12/10/08 12/10/08 12/10/11 1 Page 5 of 6 This document is controlled as an on line file. It may be printed but the print copy is not a controlled document. It is the user’s responsibility to ensure that the document is the same revision as the current on line file. This copy was printed on 5/4/2017. ES&H Manual TITLE: DOCUMENT ID: 6230 Appendix T1 Determining Equipment Class and Work Modes ISSUING AUTHORITY APPENDIX AUTHOR APPROVAL DATE EFFECTIVE DATE EXPIRATION DATE REV. ESH&Q Division Bill Merz 12/10/08 12/10/08 12/10/11 1 This document is controlled as an on line file. It may be printed but the print copy is not a controlled document. It is the user’s responsibility to ensure that the document is the same revision as the current on line file. This copy was printed on 5/4/2017. ISSUING AUTHORITY APPENDIX AUTHOR APPROVAL DATE EFFECTIVE DATE EXPIRATION DATE REV. ESH&Q Division Bill Merz 12/10/08 12/10/08 12/10/11 1 Page 6 of 6 This document is controlled as an on line file. It may be printed but the print copy is not a controlled document. It is the user’s responsibility to ensure that the document is the same revision as the current on line file. This copy was printed on 5/4/2017.