DANGERS IN ELECTRICAL WORKSHOP

WEEK ONE

Topic: Dangers in Electrical Workshop

Specific Objectives: By the end of the lesson, student should be able to

1. Mention two areas of danger in electrical workshop
2. Define temporary installation
3. State at least five IEEE requirement for temporary installation
4. State other five source of danger in electrical workshop.
5. State precautions to avoid electric shock

DANGERS IN ELECTRICAL WORKSHOP

Dangers can rise as a result of the followings

1. Use of portable equipment and tools
2. Temporary installations

• Portable equipment and tools is one of the greatest single causes of serious accidents in an electrical installation. Particular points to note when using portable equipment are:

1. Effectiveness of earth continuity conductor: (i) the earth continuity of a portable equipment used in a electrical installation should be regularly checked to avoid at least incorrect jointing on cable. (ii) Low voltage equipment should be used whenever possible.
2. Water and Chemicals: moisture impregnates insulation and is often the cause of breakdown

1. Portable tools should be handled with care (great care) in atmospheres containing inflammable chemicals. For example: fire may result from sparks at the commutator of a pistol drill in a garage.
2. Portable lamps should not be used in a garage pits, even if an earthed shield is used, because a mechanical damage to the lamp may lead to the ignition of petrol vapour.

Temporary installations

Definition: A temporary installation is an installation with an expected period of service is three month.

NB: It is important to point out that the electrician in charge of a temporary installation has a legal responsibility to ensure the safety of the installation, which includes its construction, maintenance and extension.

Temporary installation may sometimes be regarded to provide lighting or power for a limited period, for example during the construction of a building.

The requirement of the IEEE regulations for temporary installation.

1. An installation can be regarded as temporary if its expected period of service does not exceed three months.  
2. When it is necessary to retain a temporary installation in service beyond the period of three month initially estimated, it shall be completely over hauled at three monthly intervals
3. A temporary installation should be disconnected from supply and demantled as soon as it is no longer needed.
4. Every temporary installation shall be adequately protected against excess current and shall be effectively controlled by a conveniently situated switch or other means, whereby all phases or poles of the supply including the neutral.
5. In any temporary installation, the total load on a final sub-circuit to which bayonet-socket lamp holders are connected shall not exceed 1,000 watts.
6. Except in a private dwelling-house, every temporary installation shall be in the charge of a competent person who shall accept full responsibility for the installation for its use and for any alteration or extension.
7. A cable in a temporary installation shall normally be sheated with tough rubber-insulated or PVC or be steel armoured but in positions where the cable is not liable to be handled or exposed to mechanical damage.
8. Metal sheated cable shall not be used unless they are armoured.
9. Conduit should not be used in the installation unless it complies with the relevant IEEE regulator (218 & 219)
10. A temporary installation should be tested before it is put into service and shall comply as regards insulation resistance correctness of polarity.

Temporary installations tends to be fruitful sources of electrical accident/dangers. Common causes are as follows:

1. Use of cable without mechanical protection (for example PVC)
2. Lack of protective covering on switches, boxes etc.
3. Cable run over sharp edges
4. Use of unearthed brass or unskirted lamp holder.
5. Unauthorized additions to circuit resulting in overloading with a sequent fire risk.

EVALUATION

1. Define temporary installation
2. Mention two area of danger in electrical workshop
3. State five IEEE requirement for temporary installation