Vital last resort: Select the correct protective workwear for electrical workers

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Health & Safety Middle East | By: GSE Systems, Inc.

The steps necessary to correctly specify protective workwear for electrical workers are described by John Maplesden, who discusses the application of the hierarchy of controls, the implementation of mitigation measures and the specification of appropriate workwear for the residual risk associated with the shock and arcing hazards.

Introduction

Alongside any other hazards that the workplace may present, two hazards must be considered in the case of electrical workers. These hazards are electric shock and arcing.

Having identified the hazards of electric shock and arcing, the hierarchy of risk control measures must be applied to reduce the risk presented by the hazards to the lowest reasonably practicable level.

The Hierarchy of Controls is a generally accepted approach to hazard mitigation, with the most effective controls at the top of the pyramid – eliminate the hazard – and the least effective at the base – the use of Personal Protective Equipment (PPE).

Reasonably practicable means balancing the level of the risk against the measures needed to control the risk in terms of money, time or trouble. The decision is weighted in favour of health and safety so that the measures are adopted unless they are grossly disproportionate.

Protective workwear, or PPE, is literally the last line of defence against a hazard and should only be considered after all other risk control measures have been implemented.

The use of PPE is indicated when the residual risk presented by the hazards, after all risk control measures have been implemented, is considered to be unacceptable and therefore warrants its use. In other words, a risk assessment is performed taking into account all of the risks and control measures to determine if PPE is required.

Daniels states that the severity of exposure is used to select the appropriate PPE and that likelihood of exposure is used to determine when it is appropriate to use PPE.

This article discusses how to determine the severity of exposure and the likelihood of exposure to electric shock and arcing hazards in order to determine what is the appropriate PPE, and when it should be worn in any particular set of circumstances.

The shock hazard

This is a dangerous condition associated with the possible release of energy caused by contact or approach to energised electrical conductors or circuit parts.

An electrical worker can receive an electric shock by simultaneously contacting two energised conductors at differing potentials, or by simultaneous contact with an energised conductor and earth (ground).

The effects of electric shock on the body are given in IEC 60479 – ‘Effects of current on human beings and livestock – Part 1: General Aspects’.

A voltage as low as 50 volts applied between two parts of the human body causes a current to flow that can block the electrical signals between the brain and the muscles. This may have a number of effects including:

  • Stopping the heart beating properly
  • Preventing the person from breathing
  • Causing muscle spasms

The exact effect is dependent upon a large number of things including the voltage level, which parts of the body are involved, how damp the person is, and the length of time the current flows.

When an electrical current passes through the human body it heats the tissue along the length of the current flow. This can result in deep burns that often require major surgery and are permanently disabling. Burns are more common with higher voltages but may occur from domestic electricity supplies if the current flows for more than a few fractions of a second.

People who receive an electric shock often get painful muscle spasms that can be strong enough to break bones or dislocate joints. This loss of muscle control often means the person cannot ‘let go’ or escape the electric shock. The person may fall if they are working at height or be thrown into nearby machinery and structures.

The arcing hazard

Where electrical arcing occurs, perhaps as a result of accidental short circuit, the heat generated can be intense and, even if it persists for only a very short time, exposure to an arc can cause deep-seated and slow-healing burns. Engineers and craftsmen often fail to appreciate the very real risk of injury that can arise from arcing. As a result, there are several hundred serious burn accidents each year arising from unsafe working practises. The intense ultraviolet radiation from an electric arc can also cause damage to the eyes. Read More

HSME-Vital-Last-Resort
Health & Safety Middle East
| By: GSE Systems, Inc.
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