Some important information about safety when handling electrical items.
CAUTION: Mains powered appliances and devices use 240 volts Alternating Current (AC, with symbol ~). This voltage can be lethal and cause electrocution.
Tampering with electrical items can lead to serious injury or loss of life. While we believe that these items are repairable and should be repaired where possible, we do not recommend tackling these items unless you are properly trained and know how to be extremely safe when doing so.
For those of you who are interested in some of the basics of electrical repair and safety considerations involved, one of our volunteers (Alan Finlay) has written the following guidelines and information.
Please, always be safe when handling electrical items.
Basics for repairing all electrical items
Modern electrical manufacturers typically make appliances difficult to disassemble by using special fastening devices (screws and bolts) with unusual heads. These heads require special tools to remove them, and most home tool kits would not include these special tools.
Some parts of electrical appliances may be accessible by removing conventional screws or bolts. This might be applicable to fans or heaters so that the user can more easily clean or remove dust, etc. Older appliances most probably do not have the special screws or bolts, and so the user might be able to completely dismantle them, exposing themselves to dangerous voltages.
As a general guideline, if you start to dismantle a modern appliance and you find there are special screws or bolts, do not attempt to dismantle any further. Those special screws or bolts are there to prevent you coming into contact with dangerous voltages. Only a licensed electrician or suitably trained technician should remove these special screws or bolts. The Bower has such people available to assist you at our free Repair Cafes, or via our Paid Repair service. We encourage you to bring your small appliance to our Repair Cafes and to participate in the checking and repair process, under expert and safe supervision. In that way, you can learn more about how the appliance works, and how repairs can be carried out. If we can’t repair it, we can give you advice about organisations that might be able to repair it and indicative costs. If we agree with you that it can’t be repaired, we can provide advice about how to dispose of it in an environmentally sound way.
Repairing a battery operated device
Generally , battery-only operated devices use voltages of 12 volts Direct Current (DC, with symbol ±) or less. Such voltages are non-lethal and so do not require the same degree of protection.
Some devices have conventional screws or bolts (flat head or Philips head) but these can be very small. A jeweller screwdriver set might be needed to remove such small screws.
Other devices may have plastic snap fitting covers. These can be gently removed by inserting a fine blade screwdriver into the small gap where the cover meets the base.
Other devices may have glued or moulded covers that are not designed to be removed. If you attempt to remove such covers or parts, the device will probably be destroyed in the process and then cannot be repaired.
Diagnosis and repair
The first thing to check is the state of the battery (or batteries). This can be done by substituting brand new batteries, or by using a multimeter.
A multimeter can usually measure voltage (volts), current (amps) and resistance (ohms). If used for checking batteries, it should be set on the DC voltage range.
Make sure that the red lead of the meter is connected to the positive (+) terminal of the battery, and the black lead to the negative (-) terminal. The reading should be very close or slightly more than the nominal new battery voltage. If it is more than 1 volt below the nominal voltage, the battery may not have sufficient power to make the device work properly.
A common problem with battery operated devices is a bad connection between the battery and the device. This is usually due to dirty battery terminals or connectors. (Batteries should not be left inside devices that are not used for lengthy periods because some batteries can leak and cause corrosion.) The battery terminals and connectors can be cleaned using a small powered engraving tool (Dremmel) if available, or with fine sand paper or a wire brush.
Another possible problem is a broken internal wire or a faulty switch. In such cases, it will probably be necessary for the wire or switch to be replaced, and this might require soldering. Great care should be taken if using a soldering iron. Serous burns can result from skin contact with the iron, and excess heat from the iron can sometimes damage delicate electronic components. If in doubt, leave it to our experts at our Repair Cafes or Paid Repair service.
Why do some appliances have 3-pin plugs and some only 2-pin plugs?
Appliances that are ‘Double Insulated’ do not require an Earth wire because there are at least two layers of insulation between the live wires and the body of the appliance. Such appliances usually have a symbol () on their label. They require only two wires (Active, colour Brown or Red) and Neutral (colour Blue or Black).
Appliances that are not double insulated additionally require an Earth wire (Green/Yellow or Green) that connects the exposed metal parts to the Earth terminal in the power point.
Why is the Earth wire important?
The Earth wire is important because if one of the live wires were to disconnect and contact an exposed metal surface, such surface could become live and the user could be electrocuted. The Earth wire prevents this by directing the dangerous electrical current to earth via the power point and the building wiring.
What is a Safety Switch?
A Safety Switch is technically known as an Earth Leakage Circuit Breaker (ELCB). It works by detecting a small leakage current to earth (possibly due to a user touching a live part) and quickly shutting of the power to the circuit that it protects. That circuit could be several power points or lighting points in a building, or it could be just one extension lead (if a portable ELCB). ELCBs can be reset but if they keep tripping, the reason needs to be determined.
What is a Circuit Breaker?
A general purpose Circuit Breaker is a device that detects an overload (excess current) in a circuit and shuts off power. It can be reset once the problem is identified and fixed. Circuit Breakers have mostly replaced fuses in modern installations.
What is a Fuse?
A Fuse is an overload protection device. If there is excess current in a circuit, the small wire inside the fuse melts and cuts off power. Some small fuses inside appliances have a glass envelope and such fuses cannot be rewired – they must be replaced. Building fuses (typically found on switchboards) can be ceramic (re-wireable) or cartridge (replaceable only) types.