Sparks Electrical News February 2015

18 distribution boards, switches, sockets and protection

Who wants to be a kamikaze pilot? Getting to grips with SANS 10142–1 by Hannes Baard OVER the past few issues, we’ve delved

subsection (1) or (3) unless theMinister for National Health andWelfare and the Council have been consulted. (5) A notice issued or deemed to have been issued under Section 13 of the Machinery andOccupational Safety Act, 1983 (Act 6 of 1983), andwhichwas in force immediately prior to the com- mencement of this Act, shall be deemed to have been issued under this Section. Eish! The above – Section of 21 of the Occupational Health and Safety Act (Act 85 1993) – is again a prime example of how legislators mince words. What is basically says is: Your employer or boss cannot make you do a life threatening job or a job that will affect your health and/or safety if the Minister of Labour does not think it’s in your best interest and has issued a notice to this effect. I wonder if the kamikaze pilots in WorldWar II (and some modern day martyrs) had the blessing of a Minister of Labour? (Oh, sorry… that blessing would have come from a Minister of Defence…) Stay alive till next time.

permit any employee, otherwise than on the conditions specified in the notice, to performanywork on or in any prem- ises where an article or substance speci- fied in the notice is produced, processed, used, handled, stored or transported which in the opinion of theMinister is an article or substancewhich threatens or is likely to threaten the health or safety of an employee. (2) (a) The Minister shall, before he publishes a notice under subsection (1), cause a draft of his proposed notice to be published in the Gazette and at the same time invite interested persons to submit to him in writing, within a specified period, comments and representations in connection with the proposed notice. (b) The provisions of paragraph (a) shall not apply if theMinister, in pursuance of comments and representations received, decides to publish the notice referred to in subsection (1) in an amended form. (3) A notice under subsection (1) may at any time be amended or withdrawn by like notice. (4) A notice shall not be issued under

employee belonging to a category of employees specified in the notice to performwork on or in any premises on or inwhich an activity specified in the notice is carried out which in the opin- ion of theMinister is an activitywhich threatens or is likely to threaten the health or safety of an employee belong- ing to that category of employees, or that no employer shall require or permit any such employee to performany work on or in such premises otherwise than on the conditions specified in the notice; (b) That no employer shall require or permit any employee to performany work in connectionwith the carrying out of a process specified in the notice which in the opinion of theMinister is a process which threatens or is likely to threaten the health or safety of an employee, or that no employer shall re- quire or permit an employee to perform anywork in connectionwith the car- rying out of such a process otherwise than on the conditions specified in the notice; and (c) That no employer shall require or

(3) A health and safety committee or a member thereof shall not incur any civil liability by reason of the fact only that it or he failed to do anythingwhich it or hemay or is required to do in terms of this Act. (4) An employer shall take the prescribed steps to ensure that a health and safety committee complies with the provisions of Section 19(4) and performs the duties assigned to it by subsections (1) and (2). Key in subsection (1)(a) is the word ‘ recommendations’ . This means that a safety representative, a committee or committees can propose, suggest or provide advice to improve health and safety matters in the workplace. What it does not say is that it can be one-sidedly implemented by the safety representative, committee or committees without consultation with management. What it does say, too, is that if management does not seem to be interested in the issue that has been raised and it can be proven that it is, indeed, a serious situation, the safety representative, committee or commit-

quite extensively into the workings andmake-up of‘health and safety’in the workplace. The‘health and safety’ that I’m referring to, of course, cover the legislative aspects of the subject as covered and penned in the Occupa- tional Health and Safety Act (Act 85 1993). We have looked at things such as the responsibilities of employers, the responsibilities of employees and the fact that certain of the responsibilities can be delegated. To this effect, we have had an in-depth look at what the Occupational Health and Safety Act (Act 85 1993) has to say about health and safety representatives and who can be appointed as a health and safety representative – and, ultimately, how these individuals come together as health and safety committees. Therefore, to conclude the rather protracted topic on health and safety representatives and committees, we will look at the functions of the collec- tive representatives as a committee or as committees. Section 20 of the Occupational Health and Safety Act (Act 85 1993) states: 20. Functions of health and safety committees (1) A health and safety committee (a) Maymake recommendations to the employer or, where the recom- mendations fail to resolve thematter, to an inspector regarding anymatter affecting the health or safety of persons at theworkplace or any section thereof for which such committee has been established; (b) Shall discuss any incident at the workplace or section thereof inwhich or in consequence of which any person was injured, became ill or died, andmay inwriting report on the incident to an inspector; and (c) Shall performsuch other functions as may be prescribed. (2) A health and safety committee shall keep record of each recommendation made to an employer in terms of subsec- tion (1)(a) and of any report made to an inspector in terms of subsection (1)(b).

tees can inform an inspec- tor from the Department of Labour who will then take the matter further. Section 20 further states that incidents at the work- place shall be discussed and reported in writing if someone has become ill or has died because of circumstances at the work- place. Section 20 concludes with an‘instruction’to the employer by using the word‘shall’to take steps, prescribed or otherwise to ensure the health and safety representative, a committee or committees actually performs their du- ties prescribed in Section 19 of the Act. 21. General prohibitions (1) TheMinister may by no- tice in the Gazette declare (a) That no employer shall require or permit any

LV circuit breakers: a yardstick to service life By Kevin Flack, product manager for MCBs and ACBs, CBI – electric: low voltage

WHEN determining whether an installed circuit breaker should be replaced or not, safety is the main priority. When fuses were phased out in the 1950s and the changeover to circuit breakers began, the new technology required a deviation from surface- mounted installations towards distribution panels. While there are many installations from this era that are still in daily service, when those properties change hands or repairs have to be carried out, electrical contractors have to issue a Certificate of Compliance that will ensure the continued safe use of the electri- cal systems in these homes, businesses, factories andmines. Determination of the predictive life The longevity of a circuit breaker cannot be decided only in terms of the years of use. The service life will require some diagnosis by experts but could be gauged in broad terms by typical manu- facturing data that includes environmental factors; tripping and switching cycles; length of service; maintenance levels; as well as inspection andmaintenance selection. Correct selection of inspection andmaintenance levels can ensure that trouble can be avoided and ensure the circuit break- ers can be used for the longest possible time. It is a good idea to introduce periodic inspection approximately a month after com- mencement of use. Twice yearly inspect that there are no adverse environmental conditions such as steam, corrosion or rust. Every year check for dust and humidity and once every two to three years ensure that the environment is clean and dry. During these inspections examine whether there are any loose connections or damage to components as well as dust or moisture contami- nation. Look for signs of abnormal temperatures andmelted cable insulation or plating; for any discolouring; and for tripping breakers. Ensure that all barriers are in place; and test the earth leakage (EL) operation via the test button or using an EL tester or The cardinal rule is to establish why the circuit breaker tripped and remove the cause before simply switching on again. High- level short circuits will have a dramatic effect on the life of a circuit breaker so avoid unnecessary switching into known high level faults. Before switching on, check the possible reason for tripping, including faulty equipment etc., as well as the estimation of fault level and calculate the length back to the supply transformer. A low intensity trip will show no signs of carbon soot and the equipment can be re-used after precautionary checks for signs of overheating or tripping. Amedium intensity trip will show signs of carbon soot around the venting area only. In this case equipment can be reused only once insulation tests >5 MΩ and the equipment has beenmonitored for signs of overheating or tripping. For a high intensity trip there will be large amounts of carbon soot in the vent area includingmetallic residue or soot visually obvious around the handle and damage related to the fault. In this instance immediate replacement is required before reconnection. Service life approximations The service life of circuit breakers therefore depends on the sum total operational cycles and total tripping cycles on fault condi- tions and the intensity levels of those faults as well as the impact of the installed environment. This may be gauged by experienced experts who are able to safely open and test the units but this mechanically trip the circuit breaker. Inspection after tripping or fault

process is neither practical, nor cost effective. For circuit breakers and units that have been installed in excess of 25 years, a systematic replacement is called for. The units have served their intended purpose and non-trip or slow tripmay cause additional costly damage. The potential risk of malfunction exceeds the planned replacement costs. The total life cycle has not been under consideration of a single person.

Installed conditions, use and environment

Approximate service life

Indoor dry; dust free; clean air; air-conditioned; low risk of tripping; original installed nomodifications; regular professional monitoring or maintenance; closed high rated IP panel boards. Indoor light dust; no corrosive gases; low risk of trip- ping; good service levels of maintenance; thorough inspection if trip out occurred. Dust requiring regular attention; industrial contami- nation; corrosive gases; moisture; steam; sewage treatment; iron; paper or similar processing and manufacturing plants. Panel boards require constant attention to clean; service and keep production process going. Spontaneous secondary flashovers have occurred in the past; Highly modified panel boards over five year period. Excess dust; grit; corrosive moisture conditions typi- cal of mining; quarry; chemical plants. Typically workers are required to use additional PPE measures to be in the area or are limited in the area. Cable damage is constant in occurrence.

10-20 years

7-15 years

3-7 years

1-3 years

Summary For continued safe use, circuit breakers of known long installed life, or where the installed conditions are considered arduous, or risk of failure could be considered as not acceptable, require expert evaluation with a view to replacing them. Service staff employees are ideal front line personnel to identify these sites and recom- mend corrective actions. Enquiries: +27 11 928 2000

sparks

february 2015

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