COMPUTER, DATA and ASSOCIATED INSTALLATIONS (use BS7671:2018 Amendment 2:2022)
Special Installations IT, Data and computer circuits, interference, noise, spikes, surges, leakage, filters, UPS, fibreoptics, laser, safety and protection - 8 questions from a bank of questions
Computers and associated equipment incorporate power supplies that contain mains filters. These filters produce high protective conductor currents. What is the typical value of these 'leakage' currents ?
up to 1mA
up to 3mA
up to 1A
up to 3A
Which section of BS7671 covers installations where 'equipment has high protective conductor currents' (such as IT and related equipment) ?
701
740
543.7
part 2
Computers and computer networks are sensitive to electrical mains 'distortion' or 'interference'. What name usually refers to these problems ?
brown-out
noise
disturbance
blackout
What does the following image represent ? >
A sine wave with transients
A sine wave of a clean supply
A sine wave with noise
A sine wave with surge
What is the main cause of 'noise' on an AC mains supply ?
switching of large capacitive loads
switching of large resistive loads
switching of large inductive loads
radio and TV signals
What is meant by the term 'clean earth' with reagrd to a computer circuit ?
it uses dedicated earth electrodes at the supply and furthest point of the circuit
it uses a copper core of a multicore cable
it uses the steel armour of a SWA cable
it is formed by steel trunking or steel conduit
What is shown in the following waveform ?
a spike
noise
distortion
disturbance
What is the primary purpose of a UPS in a busy IT office ?
It allows 230v to remain on indefinately during a power cut
It provides a time-limited mains supply during a power cut
It backs-up data during a power cut
It maintains a steady, filtered mains supply
What is signified by the following warning sign ?
Fibre Optics Hazard
Laser hazard
electrical hazard
networks hazard
As an electrician carrying out installation work in a busy IT office, what is the main hazard associated with fibre optic networks that may be working in your work area ?
Hazard to eyes from fibre optics
Electrical hazard from fibre optics
Hazard with glass from fibre optics
heat hazard from fibre optics
As an installation electrician carrying out inspection and testing on part of the electrical installation in a busy IT office, why is it important to check and check again before isolating the IT supply circuit ?
to avoid damage or loss of data to computer systems
to avoid the risk of electric shock
to comply with IET regulations
to ensure that the job can be completed on time
Which one of the following statements is true of fibre optic systems?
they are not immune from electrical interference
they can not be bent sharply around obstacles
frequent repeaters are needed to boost the signal strength over short distances
fibre optics cannot be installed in hazardous/explosive areas
What BAND do fibre optics, CAT5 network and other data and network data cable systems fall into in accordance with BS7671:2018 ?