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PIRswith omnipresence
By Andy Douglas, Managing Director of Timeguard Limited W
hether it is providing outdoor security lighting or automating internal lights and HVAC
systems to conserve energy, PIR detectors are everywhere and, just when you thought these were products you could sell over the counter without too much thought, Timeguard comes along and rocks the boat again with a warning about LED compatibility. The company now has the right PIR switch for any application. Many LED lamps can cause current spikes at
switch-on that far exceed the normal operating current and shorten the life of the relay switch in the PIR. The poor power factor of many LED lamps can also reduce the life of the PIR. To a large extent, the choice of LED lamps with quality drivers can address these issues but, in our experience, the type of quality drivers we use across the Timeguard range are by no means adopted throughout the market, especially with lower cost LED lights. It is important to check, before specifying a PIR motion or presence detector to switch an LED light, that it is designed and rated to avoid these problems. Do not assume that the other load ratings give the LED rating. There’s no doubt that installers are getting
wise to the importance of quality componentry – wholesalers tell us that they are being asked about the make of driver used in LED lamps because they know it has an impact on longevity. The problem of spikes and power factor when using LEDs with lower quality PIR switches is not yet so high on installers’ agendas, but expect it to become so as installers begin to get called back to deal with failures. The overarching message to your customers should be to make sure a
10 | electrical wholesaler February 2014
PIR switch is rated for the job you want it to do – and increasingly that means that you need to check for an LED rating and a trusted brand.
Presence detection - good wholesale business We have made high quality, more
sensitive presence detection affordable for most users, and ensured that they are fit for purpose as the migration to LED lighting continues. You will be all too aware that there’s a growing choice of PIRs, but you need to have a good idea of the ways in which different types of detector can be used if you are to advise your customers and maximise opportunities to up-sell to the higher margin models. Motion sensors, the PIR detectors that we
are all most familiar with, respond to walking movements whereas the more sophisticated presence detectors, can sense fine movements that a conventional PIR would not pick up, such as people sitting at a desk, talking on a
PIR motion and presence detection - fully under control
phone or using a keyboard. Conventional detectors would lead to nuisance switching off and so the tendency is, therefore, to leave lights switched on all the time. As a rule of thumb, a lower cost
conventional motion detector would be used in washrooms, corridors, parking areas, basements where people will typically be moving around, while presence detectors are the best choice for offices, class rooms, libraries etc - places where people will most often be seated. In addition to presence and motion
detection you also now have the option of HF (High Frequency) detectors which can ‘see’ through and around glass, wood and stud walls. They are ideal where there may not be a direct line-of-sight throughout the area to be covered, such as in a toilet area or storage area with partitions.
Presence detection - is there really a difference? The answer is absolutely yes that there is a
Flush mounting 10m PIR motion and presence detector with light time on and light level adjustment
real difference. True presence detectors use higher resolution PIR detection than the basic models, and it is the sensor design that makes them relatively expensive. Once the exclusive preserve of specialist manufacturers, their prices have come down as the technology and the market has developed, but you still need to expect to pay a premium. As a rule of thumb, a good quality basic
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