5 31 95 Department of Electrical Engineering Computer Science ELECTRICAL SAFETY for Staff and Students in EECS Instructional Laboratories NEVER WORK ALONE If you are working with energized circuits or equipment over 50 volts peak make sure that at least one other person can see you and hear you In case of emergency DIAL 100 from any phone and notify the stock clerk on duty VOLTAGE RULES All EECS Instructional Laboratories lab kit voltages are below 50 volts peak OSHA permits unqualified persons to work on such circuits with awareness type training If you intend to work on a project using power sources over 50 volts peak you must secure permission and receive specific training from your Instructor TA or Lab Technical Personnel before any work on the project begins PREVENT ACCIDENTS FOLLOW THIS ADVICE Never hurry Work deliberately and carefully Connect to the power source LAST If you are working with a lab kit that has internal power supplies turn the main power switch OFF before you begin work on the circuits Wait a few seconds for power supply capacitors to discharge These steps will also help prevent damage to circuits If you are working with a circuit that will be connected to an external power supply turn the power switch of the external supply OFF before you begin work on the circuit Check circuit power supply voltages for proper value and for type DC AC frequency before energizing the circuit Do not run wires over moving or rotating equipment or on the floor or string them across walkways from bench to bench Remove conductive watch bands or chains finger rings wrist watches etc and do not use metallic pencils metal or metal edge rulers etc when working with exposed circuits When breaking an inductive circuit open the switch with your left hand and turn your face away to avoid danger from any arc which may occur across the switch terminals When using large electrolytic capacitors be sure to wait long enough approximately five time constants for the capacitors to discharge before working on the circuit All conducting surfaces intended to be at ground potential should be connected together over 1 02 06 02 5 31 95 ADDITIONAL CAUTIONS The EECS Instructional Laboratories 34 501 38 500 38 600 are equipped with Ground Fault Current Interrupt GFCI circuit breakers Check for leakage paths to ground when breakers trip repeatedly and the problem is not due to an overload Any equipment used in the laboratories must be equipped with a standard three prong AC plug or a two pronged polarized plug All exposed non current carrying metal parts of fixed and portable equipment that may accidentally become energized should be grounded All electrical equipment or apparatus that may require frequent maintenance must be capable of being completely disconnected from the power source Do not bring into the lab or use in the lab equipment that does not conform to these rules without specific permission from your instructor TA or Lab Technical Personnel LASER LABORATORY SAFETY Students who intend to use laser systems must read the Radiation Protection Office RPO Laser Safety Program Handbook before working with lasers Copies of this handbook are available from the 38 501 Stockroom Students must attend the RPO Safety Training Seminar if they will be using Class III or IV lasers RIGHT TO KNOW LAW OSHA HAZARD COMMUNICATION STANDARD OSHA requires MIT to inform employees and MIT requires students be informed the same as employees about potential exposure to hazardous chemicals and about the Institute s Hazard Communication Program and the requirements of the Federal Right to Know Law Your supervisor instructor and department are responsible for providing you with safety information and or training on MIT Policies and Procedures on Environmental Health Safety Material Safety Data Sheets Labeling requirements for all hazardous materials The location of the hazardous material inventory of your work area Any operations in your work area that involve hazardous chemicals and the associated health and safety hazards Safety precautions and procedures Emergency procedures The hazards of tasks done infrequently The OSHA Hazard Communication Standard and MIT s written Hazard Communication Program are on file in the MIT Safety Office and will be made available to any member of the MIT Community upon request QUESTIONS ABOUT WORK SCHOOL SAFETY Any questions about work or school safety should be brought to the attention of your immediate supervisor or instructor If problems arise that cannot be solved at this level you should contact the EECS Safety Officer Ron Roscoe Rm 38 641 253 4635 2 rroscoe MIT EDU 02 06 02 5 31 95 BASIC ELECTRICAL SAFETY PRACTICES The Institute requires everyone who uses electrical equipment to understand these safety precautions to comply with the OSHA Electrical Safety Related Work Practices standard and MIT s electrical safety policies The following safe work practices can prevent electrical shock Contact your supervisor for additional safety training if your job involves repairing installing or working on energized parts A Safe Work Practices 1 Turn off and unplug equipment instead of relying on interlocks that can fail before removing the protective cover to clear a jam replace a part adjust or troubleshoot Ask a qualified person to do the work if it involves opening equipment and creating an exposure to energized parts operating at 50 volts or more 2 Don t use an electrical outlet or switch if the protective cover is ajar cracked or missing Call FIXIT x3 4948 and report this 3 Only use DRY hands and tools and stand on a DRY surface when using electrical equipment plugging in an electric cord etc 4 Never put conductive metal objects into energized equipment 5 Always pick up and carry portable equipment by the handle and or base Carrying equipment by the cord damages the cord s insulation 6 Unplug cords from electrical outlets by pulling on the plug instead of pulling on the cord 7 Use extension cords temporarily The cord should be appropriately rated for the job 8 Use extension cords with 3 prong plugs to ensure that equipment is grounded 9 Never remove the grounding post from a 3 prong plug so you can plug it into a 2 prong wall outlet or extension cord 10 Re route electrical cords or extension cords so they aren t run across the floor under rugs or through doorways etc Stepping on pinching or rolling over a cord will break down the insulation and will create shock and fire hazards 11 Don t
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