Electrical Safety

Electrical safety in industry/house

                                                                

Electrical hazard:

Electricity is considered as hazardous/dangerous due to following reasons-

·         Overloading or short circuiting may lead to a fire.

·         Touching to a live wire gives a severe electric sock. Such   electric sock may lead to fatal accident.

·         Broken / damaged and defective switch /socket may lead to an electric shock to the user or it may cause fire due to spark.

Safety precaution while using electricity

·         Never touch/handle any electrical appliance with wet hands. Wet body acts as conductor

·         Never try to pull away a person who is victim of a live wire.

Care to be taken for:

Wiring: all wires used in electrical circuit should be covered with good insulators.

Joints in wires: all wire/electrical joints should be covered with insulation tape.

Electrical connection: all electrical connections at switches, plugs, sockets and junction must be tight properly.

Repair/replacement: defective switches, sockets or wires should be replaced immediately. Whenever any maintenance job is required; put on rubber gloves and rubber shoes, or stand on a dry wooden stand. Before staring maintenance job, the main switch should be switched off. The testers, screw drivers, pliers and other repairing tools have proper insulation on them.

Fuse/MCB: each circuit should have a fuse or MCB of proper rating. Fuse should be connected to the live wire. Lighting circuit (6Amperefor bulbs, fans, tubes etc) and power circuit (16Ampere for heaters, cooler, air conditioners, geysers etc) should be connected with separate MCB

ELCB: ELCB should be provided in main circuit with proper rating to isolate the power in case of fault or fire. Consult an expert or bonafied electrician.

Earthing: all electrical appliances must be properly earthed. By proper earthing, the danger of any electrical accident shock may be reduced.

Handling: while using an electrical appliance, hold it from its handles made of any insulating material. One should not touch the metallic body of any electrical appliance such as heater or electric iron while switched on.

Dealing with accident: in case of any short circuiting, or any accidental contact of a person with a live wire, do as follows:

·         Immediately switch off the main switch.

·         Provide him/her a support of some non conducting material such as rubber, sheet or wood.

Wire color code:

Live –RED, YELOLW, BLUE

Neutral-BLACK

Earth -GREEN

Typical house wiring-

                        

                                                      

SAFETY TERMINOLOGY

Shocks-Results in burn, injury,

Flashovers- fires, damages, Results in deaths

Faults-Results in arching, explosions and fires

Explosions in electrical equipment resulting in damage to installations and deaths

Fire hazards resulting in destruction, loss of fire and release of smoke, dust gases etc.  

                                      

  

Causes of electrical hazard   

                          

•       Exposed live conductors

•       Conductor not discharged

•       Enclosure not earthed

•       Lack of fence and lock

•       Lack of awareness

•       Miscommunication /miss-interpretation

•       Capacitor not discharged

•       Lack of ‘danger sign’.

•       Open cable trench

•       Cable not clamped properly

•       Poor illumination

•       Overloading of electrical gadgets

•       Not using safety belt

•       Internal flash over

•       Protection did not respond.

•       Lightning stroke

Current and voltage effect

                                   

Shock level at 50 Hz

Below 10 mA amperes	Not painful
10mA to 15mA	Painful shock
15mA to 20 mA	Muscle control affected
20 mA to 40 mA	Breathing affected
40mA to 80mA	MAGNITUDE OF CURRENT
Above 100mA	Severe burn, leads to death

Safety device

•      Discharged rod

•      Rubber gloves

•      Rubber shoes

•      Insulation mat

•      Insulation support

•      Insulated pliers/screw driver

•      Goggles/apron

Electrical permit

•      Line clearance for Low Voltage

•      Line clearance for High Voltage

•      Height work permit

•      Excavation permit

•      Temporary connection permit

•      Barricading

Tagging

•      Green tag for other than electrical

•      Red tag for electrical isolation

•      Tag “MAN AT WORK”

•      Message no for de-energization

•      Message no for energization 

Earthing system

•      Structure earthing

•      Tower earthing

•      Cabinet earthing

•      Equipment earthing

•      Transformer body earthing

•      Transformer neutral earthing

•      Surge arrester earthing

•      Cable rack earthing

•      Fencing/door earthing