ELECTRICAL SAFETY AWARNESS TRAINING Training Program Updated 5/5/04
Electrical Fires in the USA • Daily, fires occur due to electrical problems: defective electrical device, circuit overloading, circuit overheating, explosions ignited by electrical spark, etc. • Electricity is one of the most common causes of fire in the USA. Each year there are approximately: • 1.6 million fires (all causes) reported, • causing 3,600 fire deaths, • 18,000 fire related injuries, • $10.7 billion in property damage. Source: National Fire Protection Association, 2007
Grounding What is Grounding? • “Grounding” a tool or electrical system means intentionally creating a low-resistance path that connects to the earth. This prevents the buildup of voltages that could cause an electrical accident. • Grounding is normally a secondary protective measure to protect against electric shock. It will substantially reduce the risk of injury or death in case of shock, especially when used in combination with other electrical safety measures. • An equipment ground helps protect the equipment operator. It furnishes a second path for the current to pass through from the tool or machine to the ground. This additional ground safeguards the operator if a malfunction causes the tool’s metal frame to become energized. The resulting flow of current may activate the circuit protection devices.
Protection Overcurrent Protection • Fuses and circuit breakers open/break the circuit automatically when too much current flows through them. • This is designed to protect the wiring/equipment from overheating and possible damage – NOT THE USER GFCI (Ground Fault Circuit Interrupter) • Used in wet and other high-risk areas. • Stops the flow of electricity when there is a difference between current leaving and returning from the outlet. • Should be tested monthly • Push test button and then the reset button
Power Extension Cords and Power Strips • Extension Cords & Power Strips are for TEMPORARY use only! • They may not be run through doorways, ceilings or windows • Power Strips (Transient Voltage Surge Suppressors) FOR ELECTRONICS ONLY (Computer Equipment etc.) NOT FOR APPLIANCES (Refrigerator, Microwave Toaster, Coffee Pot, Water Cooler etc.) • Do not overload • The number of outlets on the power strip does not indicate how many devices can be connected 12
Properly Used Power Strip EXAMPLES OF A PROPERLY USED POWER STRIP • STRIP IS NOT OVERLOADED • ONLY COMPUTER (ELECTRICAL) EQUIPMENT IS ATTACHED TO STRIP • CORDS ARE KEPT NEAT • NO EXTENSION CORDS ARE ATTACHED TO POWER STRIP • POWER STRIP IS ATTACHED DIRECTLY TO WALL OUTLET-NO EXTENSION CORD IS USED
Improperly Used Power Strip EXAMPLES OF AN IMPROPERLY USED POWER STRIP • POWER STRIP IS OVERLOADED DUE TO MINI-FRIDGE, MICROWAVE, AND TWO-POT COFFEE MAKER ALL ON ONE POWER STRIP • APPLIANCES ARE CONNECTED TO A POWER STRIP (THEY SHOULD BE CONNECTED DIRECTLY INTO A WALL OUTLET) • POWER STRIP IS NOT CONNECTED DIRECTLY TO THE WALL OUTLET - AN EXTENSION CORD IS USED EXTENSION CORD IS USED WITH POWER STRIP
Damaged and Unapproved Devices Not Permitted: Cord plug with ground prong missing Damaged TVSS rated power strip Adapter enables circuit overload
Damaged and Unapproved Devices Not Permitted: Lamp extension cord, also damaged Power taps Adapter to change 3-prong plug to 2-prong eliminating ground
Container Bonding and Grounding(Static Electricity) Bonding Cable Grounding Cable Grounding Bus or Electrode 7 • Proper grounding and bonding is used to address the dangers of static electricity. • In order for grounding to protect, all surfaces must be bonded together and grounded to earth. • Static electricity is thereby released to earth as it is generated, preventing the accumulation of dangerous charges that may ignite flammable / hazardous substances.
Responsibilities Entire system must be properly bonded and grounded to the earth • Facilities • Responsible for the system up to the wall outlet (all wiring and outlets) • User • Responsible for the condition of plug and cord of equipment • Inspect equipment to ensure plugs and cords are not damaged. • Do not break off third prong or use adaptors • No Prong = Not Grounded
Electrical Safety Incidents • The following is an example of : Electrocution Due to Improper Use of Common Equipment
Background Dr. X was conducting an experiment related to plant growth. He needed to expose the plants to light for specific time-periods each day. Accordingly, he had a portable fluorescent lighting rack constructed and mounted on a wooden frame. He also obtained an electric timer to automatically turn the lights on and off. The light fixture was plugged into the timer, which was plugged into the wall outlet. However, since the timer only accepted a two prong plug, an adapter was used to allow the three prong plug of the lighting rack to be used with the two prong outlet of the timer.
The Incident Dr. X adjusted the timer so that the lights would be on and plugged the timer into a standard 3-prong wall outlet. Then another person in the lab noticed Dr. X grasping the lighting rack and appearing to be rigid. A third person grasped Dr. X by the shoulders and pulled him away from the lighting rack. CPR was performed on him until EMS arrived. Dr. X was transported to a hospital where he was pronounced dead.
The Investigation The investigation revealed the following details: • A potential difference of 397 volts was measured between the metal fluorescent light fixture and the adjacent stainless steel sink. (There should not have been any potential difference). • Both the fixture and the wall outlet were found to be wired correctly. • The light fixture was rated for 800 mA, but the lamps used were 1500 mA. • The transformer in the ballast was found to have short circuited to the case.
What Probably Happened Use of bulbs drawing more current than approved for the fixture caused overheating of the ballast resulting in melting of insulation around the transformer coil. This allowed an energized transformer wire to touch the metal cover of the ballast which in turn energized the metal fluorescent fixture. The lights probably continued to function since they were wired correctly.When Dr. X grasped the fixture, some part of him probably brushed against the nearby metal sink. This completed a circuit to ground through Dr. X, electrocuting him.
Preventing this Fatality As with many very serious accidents, a number of factors were involved, any one of which could have prevented this fatality. • If overrated lamps had not been used, the ballast would probably not have overheated and failed. • If the ground wire connection between the light fixture and the plug not been interrupted by the "cheater" adapter and the two-prong timer, the fixture would have safely shorted to ground tripping the circuit breaker when the equipment was plugged in before Dr. X touched it. • Had the standard outlet near the sink been Ground Fault Circuit Interrupter (GFCI) protected (as it should have been because it was near a sink), the GFCI would have tripped at the first flow of current through Dr. X immediately cutting off power to the fluorescent fixture and saving his life. These electrical safety violations cost Dr. X his life. If any one of them had been corrected before the incident, Dr. X would still be researching plant growth.
Don’t Let This Happen in Your Lab! 1)Follow manufacturer's recommendations for use of electrical equipment. Do not use electrical equipment for a task it is not designed for. 2) Generally, equipment used in research should have a 3 prong plug or be double insulated. Equipment with neither of these features are less safe but may meet electrical codes. A 3 prong plug must always go into a 3 prong outlet. Do not use a "cheater" plug or pull out the 3rd prong. 3) Do not use multiple cube taps in a standard outlet. If you must plug more than two pieces of low demand equipment into a standard outlet, use a fused power strip that will trip if too much power is used. 4) Make sure that any outlet near a sink or other water source is Ground Fault Circuit Interrupter (GFCI) protected. If you have a GFCI, periodically test it by plugging something into it and pushing the "test“ button. The equipment should turn off and then turn it back on.
…continued 5) If you see a person being electrocuted, DO NOT TOUCH HIM! The electricity can go though you too. If possible, remove the power (pull plug or trip circuit breaker), or use a non-conductive item (e.g. wooden broom handle) to pry him away from the contact. 6) Above all, do not disable any electrical safety feature expecting that another safety feature will protect you. In the incident described above, if proper lamps were used, the ballast could still have been defective from other causes. Also, GFCIs can be defective. That is why they should be periodically tested. 7) Check that power cords are in good condition. 8) Do not use extension cords as a substitute for permanent wiring.
Electrical Work • Electrical work is only to be performed by qualified individuals • Contact Facilities X4588 for ALL electrical work • Do not attempt to fix on your own • Attempting to repair equipment yourself may create a hazard 13
Conclusion • Know and follow safe work rules and practices • NO EXTENSION CORDS AS PERMANENT WIRING • POWER STRIPS ARE FOR ELECTRONICS ONLY • Report all unsafe conditions to Facilities X4588 or EHS X4078