Electrical hazards, examples

Static electricity hazards and nuisances are typified by the generation of large potentials (0.1-100 kV) by small charging currents (0.01-100 pA) flowing in high resistance circuits (10 -10 Q). This in part differentiates static electricity from other electrical phenomena. For example, stray currents in low resistance circuits are typically of the order 1 A for potential differences of the order 1 volt (A-4-1.3). The electric field at any point in relation to a conductor is proportional to its potential, while magnetic field is proportional to... 

Ensure that protective shields, barriers, or alerting techniques are used to protect firefighters from electrical hazards and energized areas. For example, rope off the energized area. 

During electrical protective equipment safety talks, you may want to review the electrical hazards most commonly found at your jobsite(s) and present examples of the types of electrical protective equipment you require at your company. Inform trainees where to find the equipment class and type markings and what they mean. Instruct trainees never to use defective or damaged electrical protective equipment, and show them photos of damage or defects, so employees know what to look out for. 

Electricity and electrical equipment create or contribute to several hazards. The most common ones are electric shock, heat, fire, and explosion. Electricity may produce other hazards indirectly. For example, when electricity energizes equipment, mechanical hazards may result. Some electrically powered devices produce harmful levels of X rays, micro-waves, or laser light. Certain equipment may create dangers from magnetic fields. Haddon s energy theory (see Chapter 9) helps people analyze electrical hazards and identify controls. 

An emerging technology involves combining microelectronics and power controls. Smartpower or power integrated circuits (PIC) can help reduce electrical hazards. These devices connect to a circuit and will have their own identification. The PIC will not permit current to flow to a device that it does not recognize. For example, this concept may prevent electrocution of a child who inserts a metal object into a receptacle. 

There are many kinds of hazards for materials handling activities and equipment. Some are unique to particular activities, equipment, or kinds of materials. For example, manual materials handling poses dangers that are different from the use of cranes or hoists. Electrical powered equipment has electrical hazards, while other energy sources pose other hazards, such as flammability. Mobile equipment hazards differ from hazards for fixed equipment. For... 

For example, a cleaning apparatus with no electrical hazards and no excessive concentrations of flammable materials would ... 

There are several different types of protective systems and techniques that may be used to protect people, plant and premises from electrical hazards, some of which, for example, earthing, have already been considered earlier in this chapter. However, only the more common types of protection will be considered here. 

As with any large, multi-floor facility, the BNC has general safety concerns related to electrical hazards, fall protection, confined-space entry, and similar hazards. While all of these hazards were addressed in the design of the facility, only the specialized hazards related to a high-technology research facility will be addressed in this chapter. For example, the design of tie-off points throughout the facility was critical for the safe repair of equipment, but this is a standard consideration in all facilities and so is not included here. 

The work activity includes operation, use and maintenance. Those responsible for the work, and those engaged in it, need to be competent to appreciate the electrical hazards and the control measures needed to minimise the risks to an acceptable level these issues are addressed in Regulations 14 and 16. To this end, the person responsible for managing the work should consider the work activities, the risks that arise, the measures that should be taken to control them, and who should be allowed to perform them. If, for example, work has to be done on a low voltage system which necessitates it being made dead , the supply to it needs to be isolated, the isolator locked off and a test made to prove that the isolated part is indeed dead and therefore safe to work on. Anyone authorised to carry out these safety precautions has to be familiar with the system, knowing which isolator or isolators to open and lock off and how to apply the test. The responsible person should also ensure that those who do the work have appropriate technical knowledge to do it properly and, on completion, to test it to prove its safety. 

To get the attention of the people in your organization who are exposed to electrical hazards or who you want to have a greater awareness, there must be examples to which they can relate. Some trainers like to use graphic pictures of electrical injuries for the shock potential others would rather use interactive discussion of accidents that co-workers have experienced. The reality of explaining the human effect of electrical shock and bum is probably a composite of showing what may happen and encouraging discussion of electrical hazards and electrical hazard management. It is probably important to emphasize all of the other potential results of electrical contact and state that death is, conceivably, a worst case. 

The meaning of signs should raise no questions. For example, DANGER HIGH VOLTAGE or DANGER ELECTRICAL HAZARD should be used with DO NOT ENTER , KEEP OUT AUTHORIZED PERSONNEL ONLY or another appropriate command so that people know what they should do. 

To modify relevant basic qualities of the hazard. Example Use different voltages for electrical... 

Most people are famihar with the direct hazards of electricity use, such as being exposed to an electric shock. However, electrical hazards may also be somewhat indirect, for example, when the energy from a fault severely bums an individual or causes a fire. It is imperative for mine personnel to be aware of these hazards and to avoid exposure to them. 

This section smnmarizes several MSHA-recommended safe job procedures as they relate to electrical safety. Note that these descriptions are not intended to provide detailed instruction, rather, they are intended to serve as representative examples and to familiarize the reader with the most common electrical hazards and basic recommended safe job procedures for several common job functions. The first section describes basic procedures that apply to most pieces of electric equipment. The second section smnmarizes procedmes for a coal mine shuttle car operator. FinaUy, equipment lockout procedures are smnmarized. See MSHA s On-The-Job Training Modules for additional details (MSHA 1985a MSHA 1985b MSHA 1986a MSHA 1988a MSHA 1988b). 

They would be used in complex entries, involving more than one person, hazards including moving machinery, electrical hazards, valve isolation, flooding etc. The permit would require time limits on entries, procedures, names of responsible persons etc. Most sewer/manhole entry work would not be done under a permit to work unless conditions as stated applied. However in factories for example, because of their complexity, every entry (tanks etc) should be carried out using a permit to work as the only satisfactory way of ensuring the safe system of work is complied with. 

Example of a home hazard map Electrical Hazard Chemical Hazard Physical Hazard Ergonomic Hazard... 

Potential fusion appHcations other than electricity production have received some study. For example, radiation and high temperature heat from a fusion reactor could be used to produce hydrogen by the electrolysis or radiolysis of water, which could be employed in the synthesis of portable chemical fuels for transportation or industrial use. The transmutation of radioactive actinide wastes from fission reactors may also be feasible. This idea would utilize the neutrons from a fusion reactor to convert hazardous isotopes into more benign and easier-to-handle species. The practicaUty of these concepts requires further analysis. 

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