Hazards of Electricity

The two principle hazards of electricity are that it (1) might ignite mixtures of air and flammable gases or vapors, or (2) electrocute an employee or cause serious injuries. 

15 to 20 Painful shock with control of adjacent muscles lost. Individual cannot let go. 

20 to 50 Painful shock with severe muscular contractions and difficult breathing. 

The significant factor is current flow through the body. A current of less than 1 milliamp (mA) may not even be noticed by a normal man. Above 3 mA, it becomes unpleasant. Above 10 ma, the victim is unable to let go. Above 30 mA. asphyxiation will result. Still higher levels lead to heart stoppage and death. These values are for sustained contact. Much higher levels can be tolerated for a fraction of a second. 

Working with 220/440 V switchgear can be dangerous because of the possibility of deadly arc flashes. Arc flashes occur when an arc shorts across components in a system and creates 

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Gas cylinders must be chained securely to the wall or laboratory bench (see pp. 644-646 and Appendix C). There is some hazard of electrical shock or short circuit from exposed terminals. Check all electrical connections carefully before plugging the control box into the 110-V ac line. Do not pressurize the bomb above 450 psi. 

Retention of a required level of electrical Insulation to protect against electrical breakdown, arcing, etc., with the associated dangers and hazards of electrical fires, and human safety. 

The amplifier has to offer protection of the patient from any hazard of electrical shock... 

Isolation amplifiers can be used to break ground loops, eliminate source ground connections, and provide isolation protection to the patient and electronic equipment. In a biopotential amplifier, the main purpose of the isolation amplifier is the protection of the patient by eliminating the hazard of electric shock resulting from the interaction among patient, amplifier, and other electric devices in the patient s environment, specifically defibrillators and electrosurgical equipment. It also adds to the prevention of line frequency interferences. 

A quarter of all serious electrical accidents involve portable electrical appliances that is, equipment which has a cable lead and plug and which is normally moved around or can easily be moved from place to place. This includes, for example, floor cleaners, kettles, heaters, portable power tools, fans, televisions, desk lamps, photocopiers, fax machines and desktop computers. There is a requirement under the Health and Safety at Work Act for employers to take adequate steps to protect users of portable appliances from the hazards of electric shock and fire. The responsibility for safety applies equally to small as well as large companies. The Electricity at Work Regulations 1989 also place a duty of care upon employers to ensure that the risks associated with the use of electrical equipment are controlled. 

Key hazards of electric-powered tools include burns and slight shocks that can lead to injuries or heart failure. To protect users from shock, tools must contain a three-wire cord with a proper ground. Tools can also contain double insulation or powered by a low-voltage isolation transformer. Operate electric tools within their design limitations. Recommend use of gloves and safety footwear when using electric tools. Never use electric tools in damp or wet locations. Keep work areas well lighted. 

Electrical Safety — Hazards of Electricity Sign-Off Sheet... 

This sign-oflF sheet documents the names of employees who attended this training session on Electrical Safety — Hazards of Electricity at this company, ... 

Be aware of the shock and burn hazards of electric tools, and protect yourself against them. Always wear the proper personal protective equipment for the work being performed. 

Employees using electric tools must be aware of several dangers the most serious is the possibility of electrocution. Among the chief hazards of electric-powered tools... 

The hazards of electric are welding can be avoided provided that there is adequate safety supervision to ensure that the appropriate precautions are taken, particularly when work has to be done in confmed/conducting, wet or hot locations that operators have been instructed in the safety measures and... 

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. 

If the malfunction involves a short-circuit between the hot conductor and the neutral, then the device will usually respond properly (but see below). However, if the malfunction is caused by a person connecting himself to the hot conductor then the device will usually not function in a protective fashion. This is because the purpose of the circuit breaker is not to protect people from the hazards of electrical shock, but rather the circuit breaker is installed in an electrical circuit to protect the wiring from an overload, which can result in heating the wire and causing a fire. Therefore, this device is really a fire safety device. That it can sometimes also operate to open a circuit quickly enough to avoid a lethal shock to an individual can only be considered to be a bonus. 

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