1. Safe use of extension leads
Due to the increasing demand we now place on our electrical installations, we often find during an inspection that there is an insufficient number of sockets to provide power and extension leads and adaptors have been used to make up this shortfall. While there is nothing inherently wrong with most of these devices, misuse can create potentially dangerous situations, with accident report statistics indicating that they are a significant cause of accidents and fires.
Common hazardous situations include:
- Faulty or damaged leads not being repaired or taken out of service. Damage can include damaged insulation leading to exposure of live conductors, broken earth conductors leading to absence of disconnection in event of fault, loose connections leading to overheating or conductors pulled out of connectors due to rough use or incorrect clamping of cables at plug entry points etc.
- Cheap or old equipment not complying with basic British or European Safety standards (no BS or CE mark)
- No RCD Device being used in areas of increased shock risk or on long leads whose earth loop impedance readings may limit safe disconnection by the fuse in event of fault – a particular problem when one lead is plugged into another.
- Incorrect fuse fitted for rating of lead or size of conductors leading to potential overheat and fire.
- Coiled leads (which have 2 separate power ratings, 1 for coiled and 1 for uncoiled) being overloaded with high current draw appliances and subsequent heat build up causing cable insulation to melt and possibly lead to short circuit/fire.
- Physical overloading of devices (particularly dangerous with block type adaptors)
- Trip hazards introduced or cable liable to damage through poor routing of leads.
If in doubt about the suitability or condition of your leads please consult with one of our qualified electricians for advice or to arrange a PAT test (portable appliance test) on your device.
2. What is an RCD? And why do I need one?
An RCD is a device that, in essence senses electricity going missing from the designed circuit and once a predetermined current has been exceeded will automatically disconnect the system. These are of particular advantage where the missing electricity could be flowing through you to earth (or earthed metalwork), and can limit the current flowing to the amount (typically 30 milliamps) where you still retain enough control of your muscles to let go of the item causing the shock (especially beneficial where current flow is across the heart and lungs…) and have been used to great success in preventing fatal accidents in the garden.
RCD’s are usually found in three types:
- Plug in type. Either supplied as a stand alone unit or fixed on the end of a lead.
- RCD incorporated into a socket, spur or radial at any point on circuit – provides protection to attached equipment and cable.
- RCD or RCBO (combined rcd and circuit breaker) built into fuseboard . Provides protection to all cable and points of the connected circuit(s)
RCD’s can usually be recognised by the labelling of its prescribed tripping current in milliamps (100mA for fault protection and 30mA for shock protection) and by the presence of a test button, often yellow or grey and marked with either TEST or a T. The button should be pressed at least every 3 months to confirm correct operation and to prevent the mechanism from becoming sticky.
It has been regulation for the last 20 years or so that all sockets that may reasonably be expected to provide electricity outside the building (all ground floor by exits) should be protected by a 30 mA RCD. However since June 2008 the 17th edition of the wiring regs requires that all sockets, all items of electrical equipment in a bathroom and all unprotected cable concealed less than 50 mm below the fabric of the building be protected by 30mA rcd. This applies to new work only and is not retrospective, however if your electrician is making an addition to an existing circuit, then that entire circuit (including any bonding and earthing) must be brought up to current regs (Guidance courtesy of IET and NICEIC) including addition of RCD protection.
While this latest inclusion of 30mA protection is predominantly for protection against shock, they have the added advantage of picking up wiring faults that could potentially cause fires far quicker than conventional fuses and breakers.
3. The role of testing and inspection in the maintenance of your installation.
Electricity, when uncontrolled can be very dangerous. With potential energy releases that can seriously damage persons and property, it is important to maintain safety measures and as the use of an installation changes, so the installation is kept in a safe and suitable condition.
There are several ways that an installation can become unsafe:
- Through deterioration of the safety features, either by natural wear and tear or by damage.
- Through poor design or installation work (usually by inadequately trained or instructed persons) resulting in an installation that is unsafe, unmaintainable or not fit for purpose.
- Through change of use or misuse resulting in an installation that is placed under undue stress.
Regular inspections and testing by a suitably qualified person can pick up on these situations and minimise the likelihood of accident occurring, as well as giving the maintenance team useful information about the installation that can allow preventative maintenance to be planned in a controlled and cost effective manner.
Although there is no current government legislation that electrical inspections must take place, it is the owners legal responsibility to ensure that the electrical system provided is safe and fit for use, and the presence of an electrical safety certification is seen as the best way of proving this. In addition it is likely to be accepted in a legal sense that adequate maintenance is indeed taking place. Wiring regulations based on accident statistics and prevention are released periodically, and it is to these criteria that a diligent electrician will be cross referencing electrical work by. Protecting users from harm is an essential part of any system and this relies on protective measures.
4. Why do earthing and bonding need to be checked?
Earthing and Bonding ensures that all metal (including pipework, radiators and metal casings of appliances) in an installation are kept to a safe voltage in the event of a fault arising either in the property, in the supply or even in a neighbouring property. As the electrical systems rely on earthing and bonding for safe disconnection, your electrician must check this is in place before undertaking any additions or alterations to the wiring. Please ask your electrician for more information or to have your Bonding checked.