. Light fittings must installed out reach intruder order
to prevent sabotage the security lighting system. intruder alarm system serves deterrent potential thief
and often reduces home insurance premiums. PIR detectors and ultrasonic detectors
Definition
A movement heat detector placed
in room will detect the presence of
anyone entering leaving that room. Intruder alarm systems can broadly
divided into three categories those which give perimeter protection,
space protection trap protection.
Intruder alarm systems
Alarm systems are now increasingly considered essential feature
of home security for all types homes and not just property high-risk
areas. 14.
PIR detectors are often used switch tungsten halogen floodlights because,
of all available luminaires, tungsten halogen offers instant high-level illumi-
nation. system can comprise one mix-
ture all three categories.53
A typical PIR detector.
A perimeter protection system places alarm sensors all external doors
and windows that intruder can detected she attempts
to gain access the protected property. The field view can wide 180°, shown
by the diagram Fig.
PIR detectors are designed sense heat changes the field view dic-
tated the lens system. also saves energy because the lamps are only switched when
someone approaches the protected area.53. This capability overcomes the problem of
false alarms, and typical PIR shown Fig.
Definition
PIR detector units allow householder
to switch lighting units automati-
cally whenever the area covered is
approached moving body whose
thermal radiation differs from the
background.Basic Electrical Installation Work
336
property.
FIGURE 14.
A movement heat detector placed room will detect the presence of
anyone entering leaving that room. 14.52
PIR detector and field detection.
Definition
A perimeter protection system places
alarm sensors all external doors
and windows that intruder can
be detected she attempts to
gain access the protected property. This involves fitting proximity
switches all external doors and windows. The major contribution secu-
rity lighting comes from the ‘unexpected’ high-level illumination area
when intruder least expects it. Many the ‘better’ detectors use split lens
system that number beams have broken before the detector
switches the security lighting. the event burglary
they alert the occupants, neighbours and officials possible criminal
act and generate fear and uncertainty the mind the intruder which
encourages more rapid departure.52.
FIGURE 14.
Definition
An intruder alarm system serves
as deterrent potential thief
and often reduces home insurance
premiums. This surprise factor often encourages the
potential intruder ‘try next door’
