3. 23.8 GW
34 * 700 MW
824.55 m
2700 BC
200 m
1 mil Volt

4. Engineer
Engineer will always be reminded and
look at those mistakes
Buries his mistakes
and forgets about it.
Med Doctor
vs
Engineers that makes things happen
Engineers that watch things happen
Engineers that says “WTF” just happened

5. Improper use of electricity or careless handling of electrical equipment leads to a number
of avoidable accidents every year, resulting in huge loss of productive, man-hours,
monetary compensation liability to the employer and sometimes instances fatalities.
Safety
Safety should be built into the design of electrical equipment.
Incorrect selection and application of even the most well designed
piece of electrical machinery can give rise to hazardous conditions.
Care is required in operation and maintenance of any electrical
equipment to avoid accidents.
Knowledge of equipment and systems is a must for each and every
person who operates or maintains the equipment
All electrical equipment / installations must be monitored closely for their
continued safe operation. Low Maintenance vs NO Maintenance

6. Energise, de-energise or isolation of electrical apparatuses
The competent person referred to in regulation 3.3.3 means a person or persons, who collectively hold the following:
Qualifications under the Skills Development Act, Act No. 97 of 1998 as:
a) an electrician or millwright;
or
b) a competency or competencies recognised by the Mining Qualification Authority for these purposes and has at least
two years post qualification experience in the construction, installation, operation and maintenance of the type of
electrical apparatus and reticulation systems on which he or she is required to work on at the mine.
c) has, attended a skills programme recognised by the Mining Qualifications Authority for this purpose; and
d) has two years experience in doing switching on medium voltage apparatuses.

7. A Qualified Electrician who, in relation to any duty or function, has undergone a minimum of
two years practical Medium Voltage training and experience, has done the relevant training
course, is the holder of a valid Medium Voltage Certificate and has been found competent to
perform Medium Voltage switching, linking, phasing and electrical isolations without
endangering other persons and themselves.
A Competent person who holds a valid Medium Voltage Certificate and is certified for Medium
Voltage Work and found competent by virtue of his / her experience and knowledge and may
give instructions to a Competent Person appointed for a specific Sub-Station to carry out
Medium Voltage switching, linking, phasing and electrical isolation operations.
Authorized Person
competent Person
Mechanical Persons cannot give electrical switching instructions

8. The employer must take reasonably practicable measures to ensure that where mineral oil is used as the
medium for insulation or cooling of electrical apparatus, adequate precautions are in place to address any
significant risk in the event of an explosion, spillage or burning of the oil.

9. The employer must take reasonable practicable measures to ensure that no person suffers any electrical
shock, arc flash or electrocution as a result of:
(a) exposure to electrical current flow;
(b) a person coming into contact with live exposed parts of any electrical apparatus;
(c) exposure to electricity, arc flash, all fault currents, overvoltage and surges;
(d) any electrical apparatus failing due to electromagnetic interference from other equipment;
(e) any electrical apparatus being incorrectly designed, installed, operated or maintained;
and any exposure to blasts, fires or arc flashes resulting from electrical faults.

11. Measured values = If = 65 kA
Peak Value Ip = 183.8 kA in the first 3 cycles
Test Conducted on the 27th of May 2016
Test been conducted to ensure steelwork can withstand the blast

12. Temperature reaches 35000 F or 19400 deg C
Pressure Wave develop in an the first half cycle is equivalent to an 100 ton
object coming your way.
Sound wave reaches 185.5 dB in the first half cycle of the fault == <- 9 ms
Air expands to 1670 times it`s volume and copper vaporizes to 67000 it`s
volume

13. Breaker Cleared
Fault Initiation
Protection Action

14. 30.8 cycles / 616 msec

16. 120 msec
1st Incident
Feeders to the winder blew === 2 * 150 mm2

17. 25.7 cycles or 514 msec
2nd Incident
Feeders to the surface ring blew === 2 * 70 mm2
Cable removed had 48 faults in a length of 400 m

20. Direct current { Component } give rise to unidirectional forces while alternating current { Component }
produce vibrational forces
DC Component

21. Theoretical forces between conductors in the event of a short circuit to be calculated.
F = ( 0.17 * Ip² ) / S
F = maximum force in(N/m)
Ip² = the peak short-circuit current in (kA)
S = the cable / busbar size in (m).
Rule of thumb = Maximum Mechanical Force is equal to 𝟐 𝟐 the Ip value or 2.828 times
t = 20 sec
@156 kA 3 * 630mm2

22. The employer must take reasonably practicable measures to ensure that when work is to be carried out on electrical
apparatus which have been isolated from all sources of electrical supply, effective precautions shall be taken:
i) by discharging all stored electrical energy, and
ii) testing for dead including any ring feeds by earthing such apparatus and, in the case of ring-feeds or
dual supplies of power, by earthing on both sides of the associated electrical apparatus worked on, so as
to prevent any conductor or apparatus from being made live while any person is working thereon.
Regulation 3.15