There are no specific British Standards for control panels (or alarm devices themselves), although elements of BS 4737 relate to features found in alarm equipment. This is likely to change with the introduction of European Standards which will, for the first time, require individual components to meet levels of performance and construction.
It is very important to understand how an alarm system is operated if false alarms are to be avoided. To reduce this risk, manufacturers have been making instructions easier to follow and many panels now incorporate a Liquid Crystal Display (LCD) giving plain English step- by-step instructions to guide users through the arming, resetting and disarming procedures. Read the rest of this entry »
The extensive range of equipment available can prove very confusing. Your main aim is to find a system which is easy to understand, uses proven technology and can be extended, if necessary, at a later date.
Personal recommendation is probably the best way to choose a company to install your alarm system.
Then, if the installation or system should prove unsatisfactory, you do at least have an official organisation to approach to take up your complaint and investigate the situation.
You should obtain at least three quotes from reputable installers and remember — the cheapest may not necessarily be the best value. Read the rest of this entry »
When you buy from a trader who has called at your home without an appointment, you, have seven days in which to cancel the contract and reclaim the money you might have paid. This applies to goods you buy and to work you have arranged to have done, provided the sum involved is over £35. This law covers home improvements such as replacement kitchens or double glazing, but not new building work such as home extensions. If in doubt, contact the local Citizens Advice Bureau. Read the rest of this entry »
A few sophisticated automatic cameras have a dual metering system, one to provide guidance to the photographer in the form of a viewfinder exposure display, while the other system takes a reading of light reflected from the film plane during exposure. The Olympus OM2n is an example where CdS cells provide viewfinder information while silicon cells control the exposure when the camera is set to automatic. Read the rest of this entry »
Different types of cameras use different methods to focus their lenses, but with the common aim of providing the photographer with a sharp image on the film.
Focusing is either done by guessing or actually measuring the camera-to subject distance using a rangefinder. The lens is then set manually to the correct distance, or in some cameras the range finder is coupled to the focusing mechanism. In other focusing systems the image is seen through a ground-glass screen and the lens moved until the image is sharp. Read the rest of this entry »
The home repairmen should be very cautious when it comes to repair of the household refrigerator. They should be aware of the fact that they are dealing with a very expensive product, and one that contains a very delicately balanced cooling system. One small error could damage the system beyond repair.
Replacing a faulty compressor requires special vacuum and freon filling equipment that only professional technicians can handle.
The refrigerator cooling system is not like the family automobile air conditioner. You can’t simply attach a hose and add a little freon when it isn’t cooling properly. The refrigerator is a carefully balanced, sealed system, and normally should not have a freon-loss problem. If the unit is not cooling properly, and you have determined that the compressor is running, then there are several electrical components in the system that could be at fault. Read the rest of this entry »
Specific symptoms include: 1) Food not remaining at the desired temperature. 2) Fridge cools intermittently. 3) Food in freezer section thaws out and then refreezes or is only partially frozen.
When a fridge has intermittent cooling, it is known as “spot cooling.” Spot cooling is a situation where the fridge does not cool the food adequately for a period of time and then mysteriously returns to proper operating order. The erratic behavior in the fridge is caused by one of two things: a defective defrost timer, or a moisture restriction. First, check the defrost timer. Read the rest of this entry »
There are two principal methods of wiring a lighting circuit, the loop-in system and the joint box system. In practice a circuit is often a mixture of both methods, the principal sections being loop-in with some lighting points being wired in conjunction with joint boxes to save cable and to facilitate the wiring. For both methods twin-core and earth PVC sheathed cable is used.
In the loop-in system, ceiling roses combine the functions of ceiling rose and joint box as the circuit wires are jointed at the ceiling rose terminals. The flexible cord of the pendant is connected to the rose terminals. Read the rest of this entry »
A radial power circuit is the name given to a circuit supplying a number of 13 A socket-outlets and fixed appliances using one cable which is not wired in the form of a ring but terminates at the last outlet.
The permitted number of socket-outlets (and fixed appliances) depends on the current rating of the circuit which can be either 20 A, wired in 2.5 mm2 cable, or 30 A wired in 4 mm2 cable. The number of socket-outlets and fixed appliances which can be served by a 20 A radial circuit depends also on the location of the circuit and whether the outlets are confined to one room. Read the rest of this entry »
Storage heaters require a separate circuit for each heater. This is because, unlike direct acting heaters which are switched on and off as required, storage heaters are all switched on together during the 8-hour period. They cannot therefore be supplied from a ring circuit which is based on diversity of use of various appliances; each heater must have its own circuit. Read the rest of this entry »
