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