The energy transferred down the cable digital pulses laser light as
against current flowing down copper conductor electrical installation
terms.
Non-maintained emergency lighting non-maintained system the emergency lamps are only illuminated if
the normal mains supply fails.
Perimeter protection system perimeter protection system places alarm sensors all external doors
and windows that intruder can detected she attempts to
gain access the protected property.
People People may described ordinary person, skilled person, an
instructed person competent person.
.
Mutual inductance mutual inductance henry exists between two coils when uniformly
varying current ampere per second one coil produces emf 1
volt the other coil.
Ohm’s law Ohm’s law says that the current passing through conductor under con-
stant temperature conditions proportional the potential difference
across the conductor.
Optical fibre cables Optical fibre cables are communication cables made from optical-quality
plastic, the same material from which spectacle lenses are manufactured.
Overload current overload current can defined current which exceeds the rated
value otherwise healthy circuit. Copper, aluminium, tin, lead, zinc and brass
are examples non-ferrous metals.
Mini-trunking Mini-trunking very small PVC trunking, ideal for surface wiring in
domestic and commercial installations such offices.
Non-ferrous Metals which not contain iron are called non-ferrous.
Movement heat detector movement heat detector placed room will detect the presence of
anyone entering leaving that room. They are non-
magnetic and resist rusting.
Passive infra-red (PIR) detectors PIR detector units allow householder switch lighting units automat-
ically whenever the area covered approached moving body whose
thermal radiation differs from the background.
Person person can described ordinary, competent, instructed skilled
depending upon that person’s skill ability.
Non-statutory regulations and codes Non-statutory regulations and codes practice interpret the statutory
of practice regulations telling how can comply with the law.
Ordinary person ordinary person person who neither skilled person nor an
instructed person.Glossary terms
380
Metallic trunking Metallic trunking formed from mild steel sheet, coated with grey sil-
ver enamel paint for internal use hot-dipped galvanized coating where
damp conditions might encountered
