sparks
ELECTRICAL NEWS
august
2013
This publication is distributed to electrical
contractors, wholesalers, distributors, OEMs, panel
builders, Eskom, mining electricians and
consulting engineers (electrical) as well as
libraries, members of IESSA, the Institute of
Electricians and public utilities.
January to March 2013
Sold 69, free 6 747. Total 6 816
Editor:
Erika van Zyl
Consultant:
Ian Jandrell PrEng, BSc(Eng), GDE, PhD, FSAIEE, MIEEE
Production & layout:
Colin Mazibuko
Advertising:
Carin Hannay
Publisher:
Jenny Warwick
Published monthly by:
Crown Publications cc
P O Box 140
Bedfordview, 2008
Tel: (011) 622-4770
Fax: (011) 615-6108
e-mail:
Website:
Printed by:
Tandym Print
The views expressed in this publication are not
necessarily those of the editor or the publisher.
Bright Sparks
July solution
A hospital muddle
The ambulance raced though the streets
taking the young man and his father to
the local hospital. The father was not badly
injured but the son was rushed into emer-
gency surgery. The surgeon took one look
at him and cried, "I cannot operate – that
is my son!"
Please explain!
Covering the chessboard
No, it is not possible! However you placed
the 31 dominoes, there will always be two
squares left, as this diagram shows. Trial
and error will also show that the two which
remain are always both black squares. This is
a clue to the explanation. When a domino is
placed on the board to cover two adjacent
squares, it covers one white square and one
black square. However many dominoes you
place, they will
always cover
equal numbers
of black and
white squares
But the board
with the corner
missing has 32
black squares
and only 30
white square so after placing 30 dominoes two
black square must remain and these can never
be covered by the 31st domino.
28
people on the move
Send your
People on the Move
photographs (at
least 300 dpi) and
captions to
sparks@crown.
co.za.
WouterVermeulen
,
business development
manager.
Master Power Technologies
Richard Smolak
,
national service manager.
Richard France
,
projects manager –
commercial.
SEPTEMBER FEATURES
Enclosures, earth leakage devices, circuit
breakers, fuses, surge and lightning protec-
tion, metering switches, dimmers, sockets, dis-
connectors, Certificate of Compliance, testing
and measuring instruments, tools and acces-
sories, cabling glands, flameproof.
DISTRIBUTION BOARDS, SWITCHES,
SOCKETS and PROTECTION
Earthing, lightning and surge protection,
earthing systems, surge protective devices,
fuses, protection of structures and electronic
equipment against lightning and surge, inter-
nal and external lightning protection systems,
correct cabling strategies, earth electrode test-
ing, impedancemeasurement and insurance.
EARTHING, LIGHTNING and SURGE
PROTECTION
