¢ WHAT ARTICLES WOULD YOU LIKE TO SEE? LET US KNOW: [email protected]
BRIGHT SPARKS!
GOT A SPARE HALF HOUR? PUT YOUR
LUNCH BREAK TO GOOD USE WITH
SOME PUZZLING BRAIN TRAINING.
NOT DONE A SUDOKU BEFORE?
1
A sudoku is a grid of
nine by nine squares or
cells, which has been
subdivided into nine
subgrids or regions of three
by three cells.
2
The objective of sudoku
is to enter a digit from 1
through 9 in each cell, in
such a way that each
horizontal row contains
each digit exactly once;
each vertical column
contains each digit exactly
once; and each subgrid or
region contains each digit
exactly once.
3
In the puzzle here,
several digits have
already been entered (the
“givens”); these may not
be changed. The puzzler’s
job is to fill the remainder of
the grid with digits
according to the listed
rules.
4
Warning: In spite of the
game’s apparent
simplicity, sudoku can be
highly addictive. For the
solution, see gemcell.com.
au/competitions.
THE CABLE GUY TECH GUIDE
Cable Installation Information - PART 1
General
All cables must be installed to comply with the latest
Australia Wiring Regulations.
Moisture
It is important that precautions are taken during
installation to ensure that moisture is not permitted
to enter the cable. Cut ends or opened areas must be
protected from moisture at all times, including during
pulling in. Cables, after cutting, must be re-sealed
for storage, by an effective method such as a heat
shrinkable cable cap.
Single Core Cables
The following points relating to single core cables
should be noted:
1. Single core cables carrying the phase currents of a
single circuit must be installed as closely as possible
together, to minimise inductive reactance and voltage
drop. The preferred formation for three phase
conductors is a “trefoil” or cloverleaf pattern although
flat touching formation is also acceptable. Sheaths
should be in contact with one another in either case.
2. A single core cable generates an alternating magnetic
field around itself which can cause large increases
in voltage drop and power loss due to “transformer
effect” when ferrous metal (iron and steel) is allowed
to encircle the cable. Steel racking or ladder will not
induce this effect, but the following must be observed:
a. Cable cleats may be of wood, plastic, or non-
ferrous metal but steel saddles should not be
used on single cores.
b. Where three single phase cables pass through
a steel bulkhead, they must all pass through the
same hole. Where glanding is required, it is usual
to cut out a panel and replace this with a non-
ferrous (metal or plastic) plate in which the three
or four glands are mounted.
Cable Support
Under fault conditions, single core cables used as phase
conductors in a multi-phase system may be subjected
to large electromechanical forces which tend to drive
them apart. Generally, properly designed cleats spaced
at 1500mm intervals will provide adequate support to
the cable under normal operating conditions. However
special consideration may be required if fault currents in
excess of 15 kA are anticipated.
To be continued in PART 2
TRUSTED BY AUSTRALIANS FOR OVER 75 YEARS
JUN – JUL 2019 GEMCELL.COM.AU
47