1. BEAMLINE for SCHOOLS – East Area ELECTRICAL HAZARDS SAFETY 11 th September 2015 HSE Unit 1

2. Introduction - Basics Conductors – substances, such as metals- little resistance to electricity Insulators – substances, such as wood, rubber, glass, and bakelite- high resistance to electricity Current – movement of electrical charge Resistance – opposition to current flow Voltage – a measure of electrical force Earthing – a conductive connection to the earth which acts as a protective measure 11th September 2015 2

3. Introduction - Hazards There are four main types of electrical injuries: 1.Electrocution (death due to electrical shock) 2.Electrical shock 3.Electrical burns 4.Falls 11th September 2015 3

4. Electrical Shock Current passes through the body Severity of the shock depends on: o Path of current through the body o Amount of current flowing through the body o Length of Time current flows through the body Low voltage does not mean low hazard!!! 11th September 2015 4

5. Permanent ventricular fibrillation Respiratory muscles can become paralysed Muscles contract causing you to freeze Slight tingling sensation Death almost certain: brain, heart stopped, organs badly burnt… 1A 50mA 30mA 10mA 0,5mA 2A Effects of current on human body Stopping the heart beating properly 11th September 2015 5

6. Electrical Shock Injuries Electrical burns Thermal contact burns Related arc / flashover hazards: – Start a fire – Strong blast and high pressure wave – Blow melted metal and vapors – High temperature (  10 000ºC) – UV ionization – Flammable gases or combustible dusts 11th September 2015 6

7. Using compliant electrical equipment (IEC standards, EU directives) Electrical networks sized according rules ( https://espace.cern.ch/hse-unit/ ) https://espace.cern.ch/hse-unit/ Protective devices to avoid electrical faults  Breakers  Residual current devices  Fuses How protect against electrical hazards? CERN Emergency buttons But not enough!!! 11th September 2015 7

8. Protect yourself from electricity Wear Personal Protection Equipment “PPE” Too many items plugged into a socket overheat and cause a fire. Don’t use defective equipment Turn power off before touching electrical equipment 11th September 2015 8

9. 1.If possible, disconnect the electrical supply using AUG 2.Call fire brigade at 74444 or use red phones 3.Take precautions to protect yourself and anyone else in the vicinity In case of electrical accident 11th September 2015 9

10. HIGH VOLTAGE Signs, Symbols, Tags, and Barricades are used to warn personnel of potential electrical hazards. OBEY ALL SIGNS AND BARRIERS! 11th September 2015 10

11. BEAMLINE for SCHOOLS – East Area THANK YOU FOR YOUR ATTENTION 11 th September 2015 HSE Unit 11