Intrinsic safety described Chapter under the heading Hazardous
Area Installations.
. The UPS
is plugged into the mains supply and
the computer systems are plugged
into the UPS. Fibre-optic systems dramat-
ically reduce the number cables required for control and communica-
tions systems, and this will turn reduce the physical room required for
these systems.
An UPS protect small network of, say, six PCs physically about the
size one hard drive and usually placed under the side an
operator’s desk.46
Digital pulses laser light down optical fibre cable.
The energy transferred down the cable digital pulses laser light as
against current flowing down copper conductor electrical installation
terms.
Definition
Optical fibre cables are communica-
tion cables made from optical-quality
plastic, the same material from which
spectacle lenses are manufactured.46. The light pulses stay within the fibre-optic cable because sci-
entific principle known ‘total internal refraction’ which means that the
laser light bounces down the cable and when strikes the outer wall is
always deflected inwards and, therefore, does not escape out the cable,
as shown Fig.
Optical fibre cables are communication cables made from optical-quality
plastic, the same material from which spectacle lenses are manufactured. There spark risk the
cable accidentally cut and, therefore, such circuits are intrinsically safe. Networks based the digital technology currently being used so
successfully the telecommunications industry are very likely become
the long-term standard for computer systems. Fibre-optic cables are also immune electrical noise when
run parallel mains cables and, therefore, the present rules segrega-
tion and screening may change the future.c.
Finally, remember that most premises these days contain some computer
equipment and systems.Electrical installations and wiring systems
331
The UPS plugged into the mains supply and the computer systems are
plugged into the UPS. supply.
Definition
An UPS essentially battery supply
electronically modified provide a
clean and secure a. 14.
It best dedicate ring radial circuit the UPS and either con-
nect the computer equipment permanently use non-standard outlets
to discourage the unauthorized use and overloading these special sup-
plies by, for example, kettles the cleaner’s vaccum.
Optical fibre cables
The introduction fibre-optic cable systems and digital transmissions will
undoubtedly affect future cabling arrangements and the work the elec-
trician. Electricians intending isolate supplies for testing
or modification should first check and then check again before they finally
isolate the supply order avoid loss damage computer systems.
Laser light pulses
Optical fibre cable
FIGURE 14.
The energy transferred down the
cable digital pulses laser light as
against current flowing down cop-
per conductor electrical installation
terms
