Refresher Course Oisd-154 Electrical Safety

REFRESHER COURSE OISD-154 ELECTRICAL SAFETY Presented by Anand Verma

Nov-14

Course Objectives  Be familiar with the basic concepts of electricity.  Understand the potential effects of electricity on the

human body.  Be able to recognize common electrical hazards

associated with daily operations and maintenance.  Be familiar with electrical protective devices.  Be knowledgeable of safe work practices.

Electrical Hazards  Shock – Most common and can cause electrocution or muscle

contraction leading to secondary injury which includes falls  Fires – Enough heat or sparks can ignite combustible materials  Explosions – Electrical spark can ignite vapors in the air  Arc Flash - can cause burns ranging from 14,000 degrees f. to

35,000 degrees f  Arc Blast – In a short circuit event copper can expand 67,000

times. The expansion causes a pressure wave. Air also expands adding to the pressure wave

DC effect on Human body  More than 3 milliamps (ma): painful shock  More than 10 ma: muscle contraction  More than 20 ma: considered severe shock  More than 30 ma: lung paralysis - usually temporary  More than 50 ma: possible ventricular fibrillation (usually

fatal)  100 ma to 4 amps: certain ventricular fibrillation (fatal)  Over 4 amps: heart paralysis; severe burns

AC effect on Human body

Hazards at workplace  Working on energized circuitry or equipment  Inadequate wiring  Exposed electrical parts  Wires with bad insulation  Ungrounded electrical systems and tools  Overloaded circuits  Damaged power tools and equipment  Using the wrong PPE and tools  Overhead power lines  Damaged extension cords  Unqualified workers doing electrical work  All hazards are made worse in wet conditions

Preventive Measures Proper grounding  Use PPE  Use GFCIs/RCCBs  Use fuses and circuit breakers  Guard live parts  Lockout/ Tag-out  Proper use of flexible cords  Maintain minimum 10 feet from overhead lines  Close electrical panels by Competent Person  Employee training  Ensure Competent Person on site  Use proper approved electrical equipment  Qualified person install electrical devices 

Protection System  Earthing System  Circuit Breakers and Relays  Fuses  Residual current circuit breaker  Ground Fault Current Interrupter  PPE  Insulators

First Aid for electric shock For low voltage electricity >50 V AC and 110 V DC  remove the source of electricity supply  commence CPR if trained  call the emergency number on site For high voltage electricity >1000 V  call the emergency number for your site  don’t go near the casualty  don’t touch the casualty or try to free them with anything  In hospitals , MRI, CT scan, AED may be applied.

Automated External Defibrillator

Various standards  OISD RP 110 - Recommended Practices on Static Electricity  OISD 113 -

Classification of Area for Electrical Installations at Hydrocarbon Processing & Handling Facilities

 OISD 137 -

Inspection of Electrical Equipment

 OISD-RP-147 -Inspection & safe practices during electrical

installations  OISD-RP-148 -Inspection & safe practices during overhauling

electrical equipment  OISD-RP-149- Design aspects for safety in electrical systems  OISD 173 -

Fire Prevention and Protection System for Electrical Installations

 OISD-GDN-180 - Lightning Protection

Be Safe