General Electrical Safety and Emergency Procedures

Transcription

1 General Electrical Safety and Emergency Procedures V 1.0 6/07/2015

2 The intent of this document is to provide general information to electrical contractors as to how and what steps should be implemented in emergency situations as well as general electrical safety which may be beneficial to consider. This document is not to be used as a substitute to official work cover documentation or electrical distributor s network standards. There are many safety precautions and electrical conditions which exist that have not been explained or mentioned in this document. The information provided is non case specific and should only be used for general knowledge and to encourage the reader to further research into a specific area. 2 P a g e

3 Important phone numbers Emergency 000 or 112 from mobile phone Dial before you dig Poisons information centre State Emergency Services (NSW) NSW Bushfire Information NSW Disaster Welfare Assistance Ausgrid Emergency service Endeavour Emergency service Essential Energy Emergency Service Transgrid Emergency Service P a g e

4 General Emergency Procedure Swiftly judge the incident Scan and identify risks that pose threats to safety Implement methods to reduce exposure to threats Constant monitor safety of both internal and external parties Call emergency service (Phone 000) Initiate required treatment IMPORTANT: In the event a person has become electrified on a low voltage system the rescuer must use a nonconductive material that has no moisture to remove them from the point of contact. It is recommended that contractors working on LV systems (excluding poles which require additional equipment) should have a Low Voltage Rescue Kit near their immediate work surroundings which contains 1. Rescue kit gloves 2. Rescue crook (generally fibre glass) 3. Torch (Ideally magnetic torch) 4. Burn module 5. Fire blanket 6. Pouch to house contents in a high visibility colour Note: Rescue gloves differ from working gloves as they are thicker in construction and should be discarded if used. THERE IS NO HIGH VOLTAGE RESCUE SYSTEM In the scenario that a person has come into contact with high voltage DO NOT ATTEMPT TO RELEASE THEM FROM POINT OF CONTACT. 4 P a g e

5 Courtesy of Ambulance NSW Please visit for original image 5 P a g e

6 Safety Clothing Electrical contractors should not wear clothing which is made of synthetic fabrics such as polyester, acrylic and nylon. Although P.P.E and clothing is the last line of defence, it may be the one factor that a person survives because of a catastrophic equipment failure that they may be inadvertently exposed to. If an electrical professional is passing failing equipment and an arc flash occurs a number of life threating hazards occur in a fraction of second: 1. An incredible amount of heat produced from the arc exposes the person to flash burns (even if there not directly facing the source) as temperatures rise in excessive of the surface of the sun. 2. The arc can destroy componentry with in its vicinity and create projectiles (both solid and molten) that can cause injury. 3. A pressure wave can be caused by the arc as it displaces the air which can catapult the person and other equipment 4. The flash will cause a tremendous sound which can damage hearing. It is always best practice to wear clothing which covers arms and legs manufactured from natural fibres (no blends) such as cotton or wool as well as having no metallic parts (zippers, buttons, watches, neck chains, rings etc.). Natural fibre work wear is significantly safer than synthetic as it will usually burn off the person whilst synthetic will burn and stick to an individual s skin causing much more damage. Metallic parts are also hazardous as they can become embedded into the skin which may require major surgery and skin grafts to repair the damage. There has been an incident at a power distribution company where an employee was exposed to an arc flash and the jacket they were wearing had a zipper which became embedded into their skin the entire length of their torso. Garments should be arc rated clothing and have an Arc Thermal Performance Value (APTV) which specifics the amount of protection in cal/cm² (heat protection per cm²) that will be provided to the user. Note: If garments have tears or holes the level of protection has been compromised and new work wear needs to be purchased. 6 P a g e

7 Maintaining safe distances to live exposed conductors General: Ausgrid, Endeavour and Essential Energy specify that Ordinary Persons must maintain a minimum distance of 3 meters from exposed electrical apparatus for voltages up to and including 132kV. An Ordinary Person includes licensed electricians who have not been consulted by the electrical distributors and have not had sufficient training or experience. How to know voltage of exposed conductors? Generally low voltage supplies are installed on pin type insulators (one or more small discs installed onto a rigid pin) whilst high voltage conductors are installed on disc type insulators which are roughly 250mm wide and 150mm high (dimensions can vary). To determine the voltage of the high voltage conductor count the number of insulated discs that are supporting it from the tower or pole. Generally the following voltages are installed as: 11kV is installed on 1 insulated disc 33kV is installed on 3 insulated discs Once the voltages get higher they do use more insulated discs however the amount used may differ as less discs are required for safe clearances from the support structure. For example 132kV may not have 13 insulated discs as that will be excessive for the clearances required from the tower or pole as the phase to earth voltage is 76kV (132kV/ 3) Another method is to see how high the conductors are from the ground. The higher the voltage the greater distance from ground is required as well as distance from conductors installed beneath on the same pole. There are some poles in Sydney which have 400V, 11kV and 33kV installed on the one pole so it is important not to be complacent and treat all conductors individually as they have different approach distances. 7 P a g e

8 Step potential from fallen conductors: The illustration above highlights how an earth potential rise can cause a step potential by having your feet in two different points. If you are in the vicinity of a HV fallen conductor electrical distributors state that you should either jump (without losing balance and falling) or shuffle your feet until you re at least 8 meters away. 8 P a g e