HVACR416 - Design Electrical Safety

Safety and Hazard Prevention Current is the killing factor in electrical shock Human bodies has resistance If voltage is applied, current will flow through the human body If one tenth of the current required to operate a 10 watt light bulb passed through your chest, the result could be lethal

Safety and Hazard Prevention A current of 2 to 3 mA. Will cause a tingling sensation (The m stands for milli, A is for amps) Milli is 1/1,000 of an amp

Safety and Hazard Prevention The tingling sensation increases and becomes very painful at about 20mA Currents between 20 and 30 mA will cause muscle contraction At 20 and 30 mA you may be unable to let go of the wire

Safety and Hazard Prevention Currents between 30 and 60 mA Will cause muscle paralysis and difficulty breathing Currents at 100 and 200 mA will generally cause death

Safety and Hazard Prevention Lockout – Tag Out Procedures One of the best ways to prevent electrical shock Equipment being worked on, should be disconnected from the power source and locked

Safety and Hazard Prevention The person working on the equipment should carry the only key This will prevent accidental activation of the equipment

Safety and Hazard Prevention The Power Supply Should Be Tagged With Name of the person working on the equipment What service is being preformed Reason for service Date and Time

Safety and Hazard Prevention Safety Do not work alone Learn first aid Do not wear jewelry Be careful using screwdrivers on electrical panels

Safety and Hazard Prevention Portable Electric Tools Electric tools with metal frames should have a grounding cord The grounding wire will protect the operator from electrical shock

Safety and Hazard Prevention Portable Electric Tools The grounding wire will carry current to ground This will let the breaker or fuse trip the circuit The grounding adaptor must be connected to a good ground

Safety and Hazard Prevention Non – Conducting Ladders Metal or aluminum ladders Can be hazardous Non – Conducting ladders are made of fiberglass or wood Will protect you from a shock to ground