Category Archives: Electrical Installations

Useful news and comments on commercial and domestic electrical installations.

Those green and yellow coloured wires under the kitchen sink

Home owners may have noticed in their homes there are often quite large looking green and yellow coloured wires (cables) connected to the mains water pipe, often under the kitchen sink.  There are similar cables connected to the mains gas pipe as well, if there is gas in the house. Are they important to electrical safety? well yes most definitely.  In situations where there is a fault in the house electrical system or the importantly the electricity supply system outside the house, then these cables are to help protect the persons in the house from electric shock and the home itself from fire risk.

One problem I find is these connections can become loose or broken and occupants of the home could well not even notice. These connections could be improperly made and left for many years unattended to.  If one of the cables is loose, broken or has a poor connection then under normal circumstances those living in the house would notice no difference in the electrical supply to lights and sockets. But if these was a fault then a dangerous situation could occur.

These cables and connections are important for home electrical safety.  If a home has any electrical changes such as a socket moved or a light switch moved then a qualified electrician will always first inspect these cables to ensure all is OK. If no electrical installation additions or changes are made on the property for many years then a Periodic Inspection will spot any problems. Periodic Inspections should usually be performed no less than every 10 years on a Domestic property.


Do not remove or tamper with these connections. They are labeled with Electrical Safety  Connection Do Not Remove.

If you notice any damage or disturbance of these green and yellow cables clamped to pipes then call in an electrician to have a look.

Arrange with an Electrician for a Periodic Inspection of your home at least every 10 years.  Note there should be a label on the home Consumer Unit (Fuse Box) stating when the next inspection is due.


USB charger sockets

For anyone thinking of installing a few of these widely available combined USB and 13A double sockets around the home, please be aware that electricians when testing circuits in home  will often need to know where USB sockets are and may need to disconnect/bypass them for the duration of any testing.  It would be useful to keep a note/list near the Consumer Unit (aka Fuse Box) of where they are installed. This is similar to smoke alarms, if a list is of where smoke alarms are located is kept near the Consumer Unit then it saves time if there is ever an electrical fault in the home.

Old Fuse Boxes (Consumer Units)

I am surprised at the number of very old Consumer Units (aka Fuse Boxes) I come across in homes, the type with that has rewirable fuses.  Sure these old fuses boxes probably still do OK what they were supposed to do 30 years ago, but since then the introduction of more convenient and technically superior electrical safety protection devices for Consumer Units has been available. Also these new Consumer Units are not expensive compared to the value of a home or home improvement projects.

One example of a safety improvement with the new Consumer Units is dealing with the situation where a home owner hangs a picture using a screw or nail and accidently hits a  cable buried under the wall plaster. With a new Consumer Unit very little electricity flows (not enough to give an electric shock to a human) before a switch automatically trips out to disconnect the electricity. With a rewireable fuse there will be a lot of electrical energy that flows for a little longer and a noticeable pop from the fuse when it blows, worse still it could be the screw or nail will remain live and the fuse will not blow at all!

I also tend to find that if a home has one of these old fuse boxes then the rest of the electrical installation has either outgrown its original intended use or has been fiddled with as number of times over 30 years such that it has become a hazard in places anyway.

If you have one of these old fuse boxes and want to refurbish a kitchen or bathroom, then it very likely it sensibly should be changed at the same time anyway.

Having said that, if a home owner has only budget for either a full electrical inspection or a new Consumer Unit, but not both. Then certainly I would recommend having the inspection done as the priority.

Wire Suspended Extra Low Voltage Lighting Systems

I recently had the pleasure of a job to replace two sets of wire suspended lighting fittings in a barn conversion home.  The result was excellent and ideal for an exposed beam ceiling.  It is has similarities to a track lighting system but instead has a pair of exposed wires strung across the room ceiling with the adjustable light fittings suspended from the wires at points required.   These systems have had in the past a bad name due to poor reliability of some systems and installation design complications.  But with the availability of quality reliable LED  12V lamps this poor reputation has now changed.  These new quality LED lamped systems  are overall (including any plastering, redecoration and floors up/carpets lifted for downlighters) are probably about the same price as down lighters install.  The main stream wholesalers appear to be wary of supplying the wire suspended equipment possibly due to warranty risks they may have experienced with the similar older halogen lamps systems The halogen lamped systems I personally would avoid.

This kind of stylish system could suit your home if you have a room that needs new or improved lighting but have requirements such as: very high ceilings, orangery or conservatory style, exposed beams, building conservation requirements, no access to ceiling void through floor above, fire Compartment building regulation complications, no ceiling void, need a flexible lighting scheme or simply like the look of a wire suspended lighting system.  Here is an example bought from National Lighting in Chichester :-

Wire Suspended 12V Lighting

It could have its uses in a Retail display environment as well.

If you are interested in one of these systems then I suggest care is taken with the selection of your electrician to design, select the products and install it. Reasons being, there is a specific section in the UK Electrical regulations that covers these systems, matching the various components in the systems is important for reliability and finally but important to the resulting effect there are choices to be made on the colour and brightness of the light from the LED lamps.

Lamps Overheating

There are still a fair few lighting fittings in use where changing to LED or CFL lamps (bulbs) is impractical, for example track or suspended lighting systems.  If replacing halogen lamps in these fittings then take care to install the correct wattage lamp.  For example many smaller light fittings have a maximum incandescent/halogen rating of 40 Watts.  Some of the ceiling lights arrays used in kitchens only take 35 watt lamps.  Fitting an brighter higher wattage lamp will very likely result in the light fitting to overheat resulting in damage to the fitting, early failure of the fitting, possibly an electrical fault and in a worse case a fire.

Checking the maximum rating of replacement lamps that can be fitted is an important safety measure.

Choices For Domestic Lighting Dimmers

It used to be fairly simple to select and install a dimmer for home lighting but it is now a little more complicated with the very common use of LED and Compact Fluorescent lighting. Making the wrong compatibility choices can result in flickering lights or/and a poor dimming range of adjustment  Under sizing a dimmer mean it will not last long.  Trying to dim lamps that are not designed to be dimmed will simply not work.  There are also complications to consider with any two way switching of the lights.

Careful planning is also needed if you have a dimmer already installed on filament/Halogen lamps but wish to change to LED lamps. Typically this would be a swap from Halogen GU10 to GU10 LED direct replacement lamps in kitchen down lighters.  Not only will the LED lamps need to be of a dimmable type but the dimmer needs to be compatible with the new lamps.

A good electrician will be able to design and install a reliable solution that best suits the requirement and budget.


LED Lamp Colours Do Vary

When choosing you new low energy lamps it is well worth making sure you have the shade of white that suits the room and the type of lighting you want.  Take the trouble to look on the box to see what you are thinking of buying.  Generally the colour of white can be bought in the range from 2700K to 4000K.

2700K is a warm white colour that replicates halogen and old style incandescent lamps.  This might be what you would need if mixing new LEDs with order style lamps or for use in relaxation rooms such as a lounge or bedroom.

3500K is a noticeable whiter shade than 2700K which may suit a bathroom or kitchen.

4000K is a bright clear white that may suit a white brightly decorated bathroom or kitchen. It offer a very clean modern look.

4000K and upwards to 5000K is sometimes called “daylight”.

While looking at the label on these new lamps you will notice they are rated in Lumens as opposed to Watts. This is something we will all have to get used to because simply buying an old 100 Watt bulb is not something you can do now.

For any spot light lamps such as GU10s and downlighter take care to check the beam width specification as well. They can vary for example between 35 degrees to 60 degrees. Importantly a wider beam width means you can use less downlights for a given size of room, but take care to ensure the end result gives the desired level of light because wider beam width usually means a lower lumen output compared to a narrower beam width. Hence getting an electrical contractor who has experience with light level design is important.

Often places that sell these lamps will have a few on demonstration side by side so you can see the difference.  I usually carry a few in my stock so I can demonstrate to customers the differences.



Commercial Office Power Circuits, Safety

In the latest UK 2015 electrical regulations there has been an improvement to safety for power (13A sockets) circuits in commercial environments. For a new circuit it is more difficult to justify not using a RCD (Residual Current Device)  safety device in addition to the normal Fuse/Miniature Circuit Breaker. RCDs generally are considered a device that protects persons from accidental electrical shock. Whereas Fuses and Circuit Breakers protect against circuit overload that for example could either result from a live wire accidently touching earth or lessor level of overload that could cause a fire.

RCDs are a significant improvement to electrical safety but surprisingly in commercial (office) environments they have not been installed a commonly as one might expect.  Besides the fact the previous regulations did not demand an RCD should be fitted so to save money they were left out, there also has in the past been a concern that numbers of computers on one circuit with an RCD could trip accidently with very unfortunate consequences.

RCD devices are now more readily available for three phase commercial Distribution (fuse) Boards and at more reasonable prices.  Also careful design of the number of sockets on a single circuit can avoid the problem of accidental or nuisance tripping out of an RCD.

In the depths of our winter is the time when office staff may bring in from home or buy extra portable heaters for use at their desks.  Particularly with electrical installations without RCDs this would be a very unwise practice.  The office provided equipment would only be plugged into circuit that was designed for that use and that equipment would have been PAT tested regularly anyway.  If a non PAT tested old heater is plugged into a socket that was intended for low power electrical load and does not have an RCD, then it can result in safety issues.

A few days ago I attended on a fault where an office user reported a smoking and sparking 13A socket outlet.  In this case there was a portable heater plugged in and the heater had been PAT tested.   But the circuit with everything else plugged in was just into overload levels which in turn had stressed what was probably a loose connection in the wiring. The connection had overheated and burnt the back of the 13A socket and wiring.

Those in small businesses responsible for requesting and engaging electrical maintenance should  perhaps make enquires as to whether RCDs are installed on the office 13A sockets, ensure PAT testing is undertaken regularly, do not allow non business provided heating equipment to be plugged to office 13A circuits and importantly when arranging the Periodic Testing of the office electrical installation ensure that part of the brief is for a realistic sample of the wiring connection screws to be checked.


Ceiling Down Lighters Melts Cable


I found this today in a loft above a bathroom.  It is not a very good picture but you may just about be able to see the electrical cable feeding downlighters has had the sheath melted and the insulation damaged.  What appears to have happened is work in the loft had disturbed the cables resulting in them lying on or close to a halogen lamp of downlighter without a frame.  These lamps run very hot and as you can see it has melted a cable. This particular type of lamp is a GU4 type which can be found in kitchen and bathroom downlighters without a protective frame or cover around. It operates at 12V (not normal domestic 230V) for a longer life. This means there is a often little box near each lamp called a transformer that converts the 230V to 12V.

This is a maybe a reminder that home electrical installations should be inspected regularly to try to avoid problems such as this.  The new 2015 Electrical Regulations now state that inspection of loft spaces has to be part of a BS7671 periodic inspection of a domestic propery.  As a bonus a good electrician at the time of an inspection will be able to advise on electrical safety improvements, low energy  choices, fire safety options and convenience improvements.  Also be careful who you let lose in your loft to do any work!

If you have any of these GU4 lamps in light fittings in your home then maybe it is time to think about changing them for LED downlighters anyway.  Particularly as some of these open frame type fittings  in a kitchen fire scenario will allow heat and smoke almost immediately through into the ceiling cavity.  New replacement quality LED downlighters run at lower temperatures, are often fire rated to reduce the speed at which a fire could spread, are virtually maintenance free and usually can have a cage option on the back of them so roof/cavity insulation can still be closely installed over the top.