The Institution of Certificated Mechanical and Electrical Engineers, South Africa

Welcome to another edition of the Western Cape News Bulletin.
We have our normal articles in this news bulletin. GCC exam questions and answers and some items of interest from Safenet
Africa.
Lastly we have decided to bring you the main part of the article on the Electrification of Cape Town, titled “Lighting up the Fairest Cape”. This section will be in many parts and we trust that it would be of interest to our readers.
I trust that you will find the content of this news bulletin interesting enough to pass on to your colleagues and friends.
Chris Schnehage
Tel: 083 326 8023 email: chris@boron.co.za
Editor: Henriette Venter email: vencon@netactive.co.za

Local Branch news:

Activities of the branch since last news bulletin were as follows:

On 15 July a group of us went to Koeberg power station’s information centre where we were briefed about the Ankerlig
peaking generation diesel powered turbine installation at Atlantis. The presentation was most interesting. Then we went to the site and had a look at the installation. It really was mind boggling to hear what the consumption of each turbine is.
On 19 August we visited the COATEC works near the Killarney race track. This was an interesting visit as well and we were treated with a braai and some refreshments.

The line up for the next few months is as follows:

21 October 2008 – talk on "Developments in Electrical Power System Protection".
November 2008 – Possible visit to SAPPI Kraft plant in Montague Gardens.
November 2008 - Visit to Syncorp in Epping.

Should any member have an interesting visit at your factory or work place, please let us know so that we can arrange such a visit. Or alternatively, if you have an idea for a talk that we could arrange, please let us know and we will attempt to find someone to present.
We look forward to seeing you at one of our functions.
Ciao for now!

Safenet - Thought for the day: Does the Occupational Health and Safety Act, 1993 prescribed the maximum length of a ladder?

When conducting audits we often find that employers use very long free standing ladders. In some industries it is quite common
to find that ladders of up to 14 meters long is being used. The question now arises as to whether or not the Occupational Health
and Safety Act, 1993 and incorporated Regulations contain any requirement pertaining to the maximum length of ladders.
General Safety Regulation 13A(3)(a) states "No employer may permit that a ladder which is required to be leaned against an
object for support be used which is longer than 9m".
The reason behind this requirement is simple as the legislation requires that any ladder which is leaned against an object for
support must be held into position or be secured / tied to the structure. The most common practice is that another employee
will stand at the base of the ladder as to prevent the ladder from moving. It would be difficult for the person standing at the base to control any movement even should the ladder be short. Even more so should the ladder be in excess of 9 meters long.
This legal requirement may pose a problem to some employers as there may be good reason why ladders longer than 9 meters
need to be used. It may be difficult or impossible to bring a cherry picker into an area resulting in the employer having little choice but to use a ladder longer than 9 meters. If this is the case what should the employers do?

The first option is obviously to find another way of doing the work safely. It may for instance be possible to use a scaffold
in areas where cherry pickers could not be used. This would be in line with the provisions of General Safety Regulation 6
which states "No employer shall require or permit any person to work in an elevated position, and no person shall work in
an elevated position, unless such work is performed safely from a ladder or scaffolding, or from a position where such
person has been made as safe as if he were working from scaffolding;
If a legitimate reason exists why only ladders longer than 9 meters could be used the employer can apply to the
Department of Labour for exemption from the provisions of General Safety Regulation 13A(3)(a). Section 40 of the
Occupational Health and Safety Act, 1993 allows for any employer to obtain exemption from any provisions of the act
or regulations. To be exempted from the provisions of a regulation the employer must send a formal letter to the
Department of Labour in which this request is made. The request should contain:
1. Reasons why the legal requirement cannot be complied with. Additional to the reasons given the
  employer must also state which additional requirements will be complied with as to ensure the safety of the employee. Exemption will not be granted by the Department of Labour should they be of the opinion that the request was made due to financial reasons only; and
2. A letter signed by the Union and Health and Safety Committee. This letter is required as the Department of Labour wants to ensure that both the Union and Health and Safety Committee were involved in the process and are happy with such a request.

PLANT ENG. Nov. 05 [2.1] (Compulsory)

Question
A three-phase, 15,5 MW power generator supplies a 5,5 MVA step-down transformer through a 5 km line.
Determine the breaking capacity needed for the high-tension and low-tension switches of the transformer if the power factor is 1.
Generator reactance 10% and resistance 1%; Transformer reactance 8% and resistance 1%; Line conductor reactance 0,5 Ω and resistance 0,67 Ω/km; Line voltage 20,5 kV. (12)

Answer:
Lets use the ohm notation method. Use line voltage of 20,5 kV as a base. Consider the generator first:
The p.u. impedance is at 15,5 kVA because the p.f. is unity. (For the answer download the Pdf version of the newsletter)

OHSACT JUNE 2008

Describe the FOUR levels of competency of a competent person as given in the GMR and also give the conditions where those competent persons must be designated.
Answer: 1(a)(b)(c)(d)
In terms of the GMR, under what conditions may a person work on or near moving or electrically alive machinery?
Answer: 5 (1)(2)(3)
List the requirements to which the devices installed to stop and start machinery, shall comply with.
Answer: 6 [1](a)(b)

OHSAct, June 02 [4]

List FOUR steps a user shall take to render moving or revolving components of machinery safe, where the components are not in such a position or of such construction that they are as safe as they would be if they were securely fenced or guarded.
Answer: 2 (a)(b)(c)(d)(e)
In terms of the EMR, give the requirements with respect to the following:
1. Electrical control gear for electrical installations and power lines
2. The placing of a switch, circuit breaker or fuse in the neutral conductor
3. The making and labelling of controlling apparatus
  Answer: 6 (1)(2)(4)
In terms of the EMR, what are the requirements for the space for operating and maintenance staff of switchboards?
Answer: 7

Electricity in Cape Town - Part 1 of “Lighting up the Fairest Cape 1895 to 1995”

INTRODUCTION
When Sir Francis Drake rounded the Cape of Good Hope on a fine winter's day in the year 1580 on his way home to England, after having spent three eventful years travelling literally around the world, he was so impressed by its natural beauty that he was inspired to pen the following immortal words in his diary.
This Cape is a most stately thing, and the fairest Cape we saw in the whole circumference of the earth.
In the following pages the development of the electricity supply industry in this "fairest Cape" in all the world is traced from its inception in the closing years of the nineteenth century right up to the present day. In essence, it records the contribution made by the City of Cape Town's electricity undertaking in the transition from the gas lighting era of the last century to the wondrous new age of electricity as we know it today. Although the approach adopted is largely chronological, the historical record has essentially been subdivided into two main sections, namely the generation of electricity on the one hand, and its transmission and distribution on the other.
Throughout, all references to "the Council" means the Council of the City of Cape Town, and "the Department" refers to the Council's electricity undertaking. In the first section the various generation sources - the power stations - are each considered in turn from the time of their construction up to the present day. Why were they built? Why were they built where they were? What were the problems experienced? These and other related matters are all dealt with in this section.
In the next section attention is given in a similar manner to the development of the transmission and distribution systems, namely that extensive network of interconnected overhead mains and underground cables that convey the electricity generated in the various power stations to the homes of each individual consumer. The progressive growth from the initial and rather basic 110 V direct current system up to the technologically advanced 132 000 V alternating current system of today, is dealt with in some detail. Why the change from direct current to alternating current? And what was the rationale behind the progressive move to higher and yet higher transmission voltages? Then finally, in the closing sections, consideration is turned to various support services and other items of special significance or importance. How is the interconnection of the generation and transmission systems managed and controlled? Also considered are matters such as the innovative application of commercial principles that so successfully stimulated the growth of the domestic load in the 1930s, and how the street lighting system has evolved from the early arc and incandescent lamp installations to the modern gaseous discharge systems now lighting our highways. Overall, this publication is intended to commemorate the centenary of the City's electricity undertaking, from its inauguration in 1895 right up to the present day. Over this period the undertaking has grown from strength to strength, and the enviable reputation that it enjoys today for excellence and service is due in no small measure to the staff, that band of dedicated men and women who have all either individually or collectively contributed to its success.

DAWN OF A NEW AGE
From the very earliest days man had been only too well aware of the awesome power of electricity as so vividly displayed in the form of lightning. But it was not until the nineteenth century that a number of epoch-making scientific events opened the way to its practical exploitation in the service of man. These momentous events were the invention of the dynamo by Michael Faraday in England in 1831, following his discovery of the principle of electromagnetic induction the same year, and the invention of the first commercially practical carbon filament incandescent lamp by Thomas Edison in America towards the end of 1879, when he at last realised his dream of a "wire in a bottle". Before this time the only form of electric lighting available was provided by the arc lamp, invented by Sir Humphry Davy in England as far back as 1801 while director of the laboratory at the Royal Institution in London. Some years later, in 1813, he appointed as his assistant the young Michael Faraday whom, incidentally, he later declared to be his greatest discovery. It was only natural, therefore, that London should be one of the first places in England where the new arc lamp was shown to the public, with demonstrations in Trafalgar Square and along the Victoria Embankment. But the widespread exploitation of electricity for lighting had to await the perfection of the dynamo as a generator of electricity many decades later, followed by the invention of the first efficient arc lamp system by Charles Brush in America in 1878, and Thomas Edison's incandescent lamp a year later. Edison was quick to exploit his new discovery and used every opportunity to promote it not only in America, but also further afield in Europe. He even opened a small generating station on London's recently constructed Holborn Viaduct to demonstrate his new lamp. Steady progress continued to be made, and well before the turn of the century considerable advances had been made in the development of the dynamo as a practical and commercial generator of electricity, not only in England and Germany, but also across the Atlantic in America. With the practical exploitation of these inventions the wondrous new age of electricity had finally dawned, an age that was to have quite unforeseen and far reaching repercussions on an as yet quite unsuspecting world. A century ago, who could possibly have foreseen such modern day wonders as radio, television and computers and the impact they would have on our lives?

ELECTRICITY COMES TO CAPE TOWN
An Awakening of Interest But despite Cape Town's relatively remote location at the tip of Africa it was not long before the wonders of this new age of electricity were revealed to its citizens. The early history of electricity in Cape Town apparently goes back at least to about 1861, when on the occasion of a visit to Cape Town by Prince Albert, a public-spirited citizen, a Mr Bishop, offered to illuminate the prominent Commercial Exchange building in Adderley Street "with electric light on the roof". It is not clear, though, whether this generous offer was accepted. Incidentally, the Commercial Exchange building was demolished in 1893 to make way for the General Post Office, which building in turn came down more recently, with the present OK Bazaars now standing on this site. Also, by way of passing interest, it might be mentioned that Adderley Street only acquired its new name in 1850, having previously been known as the Heerengracht. It is also recorded that several years later, in 1879, the town was visited by a touring group grandly styling themselves the Scientia Studiosa Company. The group was under the directorship of a most enterprising showman who by advertisements in the local newspapers of the day, invited the "art and science-loving public of Cape Town and neighbourhood to witness a select and unrivalled collection of electrical illuminary art never before witnessed in South Africa". In this sensational manner electricity, the commodity so commonplace and taken for granted today, was for perhaps the first time more extensively introduced to the citizens of that period. Then the following year Cape Town saw electricity put to more practical uses when the steamship "Trojan", one of the first ships to be equipped with an electric lighting installation, put into Table Bay. Apparently this lighting did not compare at all favourably with the City's gas lighting installation, which was then firmly established having been introduced in Cape Town as far back as 1847, with all the more important streets being lit by gas by about 1870. Most people accordingly viewed this new form of lighting with mixed feelings and expressed grave doubts as to whether it would ever become a serious competitor to gas lighting. It must be remembered, though, that at this time electric lighting was still very much of a novelty, even in Europe. Very few had as yet seen the new incandescent lamp that was soon destined to displace the arc lamp, and it was only after the Paris Electro technical Exhibition of 1881 and the Crystal Palace Exhibition in London the following year, that there was an awakening interest and awareness of this wonderful new form of lighting, with several manufacturers taking advantage of the opportunity that these exhibitions presented to display their newly developed incandescent lamps.

To be continued.