CIRCUIT PROTECTION CHECKLIST ESSENTIAL FOR ELECTRICAL SAFETY

THE IMPORTANCE OF HAVING A CIRCUIT PROTECTION CHECKLIST IN ELECTRICAL SAFETY

Before a system is designed or when unexpected events may occur, circuit designers should ask themselves the following questions:

What is the normal or average current expected?

What is the maximum continuous (three hours or more) current expected?

What inrush or temporary surge currents can be expected?

Are the overcurrent protective devices able to distinguish between expected inrush and surge currents and open under sustained overloads and fault conditions?

What kind of environmental extremes are possible? Dust, humidity, temperature extremes and other factors need to be considered.

What is the maximum available fault current the protective device may have to interrupt? Is the overcurrent protective device rated for the system voltage?

Will the overcurrent protective device provide the safest and most reliable protection for the specific equipment?

Under short-circuit conditions, will the overcurrent protective device minimize the possibility of a fire or explosion?

Does the overcurrent protective device meet all the applicable safety standards and installation requirements?

Answers to these questions and other criteria will help to determine the type of overcurrent protective device to use for optimum safety and reliability.

CONTENTS OF FIRST AID KIT/ BOX - WHAT'S INSIDE YOUR FIRST AID BOX

FIRST AID KIT/ BOX CONTENT BASIC INFORMATION
What Should Be The Content of your First Aid Emergency Kit or Box?

Impact on first-aid provision if risks are significant. First aiders may need to be appointed if risks are significant. This will involve a number of factors which must be considered, including:

➤ training for fi rst aiders
➤ additional first-aid equipment and the contents of the first-aid box
➤ siting of first-aid equipment to meet the various demands in the premises. For example, provision of equipment in each building or on several floors. There needs to be first-aid provision at all times during working hours
➤ informing local medical services of the site and its risks
➤ any special arrangements that may be needed with the local emergency services.

If employees travel away from the site the employer needs to consider:
➤ issuing personal fi rst-aid kits and providing training
➤ issuing mobile phones to employees
➤ making arrangements with employers on other sites. Although there are no legal responsibilities for nonemployees, the HSE strongly recommends that they are included in any first-aid provision.

Contents of the first-aid box
There is no standard list of items to put in a first-aid box. It depends on what the employer assesses the needs to be. Where there is no special risk in the workplace, a minimum stock of first-aid items is tabulated below.

Tablets or medicines should not be kept in the first-aid box. Table is a suggested contents list only; equivalent but different items will be considered acceptable.

SAFETY ON WORKING OVER OVERHEAD POWER LINES BASIC INFORMATION

Statistics on accidental electrocution show that quite a few of them involve work on or near overhead electric lines. Work on overhead lines is only to be done by qualified electrical lineworkers.

Many times, due to the need to maintain service continuity, the lines are kept energized while work is being performed on them. Lineworkers must be well trained to perform such tasks using safe practices, appropriate personal protective equipment, and insulated tools.

When planning for work on overhead lines, however, one should always try to make the safest choice, which is to put the lines in an electrically safe work condition. Grounding the lines to create an equipotential zone within which a lineworker can be safe is advisable while working on overhead lines.

Work on or near overhead lines requires unique safety analysis because

a) The overhead lines can change position due to wind or other disturbances.
b) A person working on the lines is not usually in the most stable position.
c) The voltages and energy levels involved with overhead lines are often large.

Working near overhead lines, or near vehicles and equipment that could contact overhead lines, requires electrical safety training even for nonelectrical personnel.

The National Electrical Safety Code¨ (NESC¨) (Accredited Standards Committee C2-1997) is a key document that gives significant detail regarding the safety rules for the installation and maintenance of overhead electric supply and communication lines. NFPA 70E-1995 also mentions safety around overhead lines in Part II.

The OSHA regulations that cover work on and near overhead electric lines are 29 CFR 1910.269 and 29 CFR 1910.333 for general industry, and 29 CFR 1926.955 for the construction industry.