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Electrical Fire

What causes an electrical fire?

Electrical fires have been at the forefront of the news a lot recently due to several high profile events, but how much do we know about what causes an electrical fire, how can we prevent them happening and what can we put in place to help contain them if they do break out?

 

Electricity is often overlooked as a potential source of fire as there is no visible flame, yet around 28,000 fires in the home are reported each year to have started from an electrical fault, accident or misuse of equipment. On New Year’s Day 2018, an eco-home that took six years to build and previously featured in the TV programme Grand Designs was burned to the ground. The owner reported that it started in a junction box downstairs. Jasmine Dale, the owner, was quoted in The Telegraph saying: “The fire was caused by a freak electrical fault. I was in the house just a few moments before the fire broke out, and there is a junction box downstairs with many electrical wires.”

 

Such was the devastation of the fire, the house was completed destroyed and we’re never likely to know the root cause of the fire within the junction box. There are however several possible causes that using good engineering practice and installation methods can be minimised. The phrase “many electrical wires” is worrying. Most standard domestic style junction boxes are designed to take a maximum of 4 cables and have 4 cable entry points. Having too many cables bunched together will affect how the heat dissipates from the cables, increasing the ambient temperature.

 

Most junction boxes have screw terminals and if these are not fixed correctly, the resistance is increased in the circuit. Where resistance is raised, there will again be more heat given out by the circuit. Loose terminal screws are often a source of electrical fire because of this, and all electrical terminations should be in an area suitable for regular inspection so they can be tightened as required. They are not suitable for mounting behind plasterboard and forgetting about. Special maintenance free connectors and installation methods can be used for areas that cannot be accessed in the future. Many electricians or DIY’ers continue to use junction boxes as they are cheaper.

 

It is also possible, if the termination was poor within the junction box, that a short circuit could have arisen from two bare cables touching, or being too close, causing an electric arc. An arc has a huge amount of energy which could start a fire if the circuit breaker did not operate as it should (if the circuit has been poorly designed). It is important when adding a new circuit, or modifying a circuit, that you ensure that the maximum amount of resistance in the circuit allowed is not exceeded.

 

Junction boxes are also not a one size fits all. Some smaller units are only rated at 5 amps. Larger ones tend to be 20 amps. When selecting your materials, ensure that they are suitable for the job at hand. All parts of electrical systems should be to the relevant British Standard, and marked accordingly. Only use reputable suppliers and be cautious as due to the rise of online marketplaces, lots of cheap, sub-standard counterfeit accessories are being sold on a daily basis.

 

The environment that the box is placed in should also be considered especially with regards to insulation and the box should be of a suitable material for its environment. Since the introduction of Amendment 3 of the wiring regs, all consumer units in domestic settings need to be constructed of a non-combustible materials, usually metal. A metal enclosure with suitable sealed knockout holes will contain a fire within it, stemming the spread. Envirograf manufacture an excellent item called the Envirobust Tube – a plastic tube that bursts open at 70℃ that contains a fire suppression liquid.

 

Electrical fires are not only caused by DIY installers, faulty equipment or poor install methods. Appliances cause a large amount of fires, most notable the fridge that was the reported cause of the tragic events at Grenfell Tower in 2017 where 71 people lost their lives. Use them in the manner they were intended, protect them from water, and make sure you register them with their manufacturer when you purchase them to be notified of any product recalls. Don’t leave electric heaters unattended and keep them away from curtains. Ensure they are kept in good working order, check cables for fraying and any signs of burning or scorching. If a fuse blows, make sure you replace it with one of the same rating. A 13a fuse in a thin cable won’t protect it, and could cause a fire. If the fuse keeps blowing, it’s because there’s a problem – get it fixed or replace the appliance.

 

Overloaded extension leads are also a large cause of fires both in the home and at work. Avoid plugging in high powered devices (as a general rule, things that produce heat such as kettles, heaters, cookers use the most power) into extension leads, this useful calculator will help, but is also complicated by the fact lots of extension leads on sale now are not rated at 13a. Some 10a and 5a leads are available, and are cheaper as they use thinner cable, but should only ever be used for low powered equipment such as IT or audio/visual equipment & lamps. It is recommended that extension leads are never used as a permanent fixture, however we all know this isn’t practical, so be careful.

 

Fires are not only started in the home or office. In January 2018 a fire broke out on the rooftop of Trump Tower in New York, a 58-story skyscraper built in 1983 by the man who went on to become the 45th President of the USA, Donald Trump. It was reported to be caused by an electrical box in a cooling tower and rooftops of large buildings often contain a large amount of plant, most notably air conditioning systems. In this instance, it was actually spotted by the Secret Service who monitor the building for threats and it was dealt with quickly and easily by the FDNY with 3 minor injuries to crew working at the blaze. We’ve not all got the Secret Service monitoring our buildings, but it goes to show that early detection is important in all cases, and this can be done in residential, commercial and industrial environments by the use of fire detection systems, allowing a small fire to be tackled with appropriate extinguishers or the building to be safely evacuated while you wait for Fire & Rescue. Plant rooms and areas are always a risk as they contain lots of equipment, are mostly left unattended and have high ambient temperatures.

 

Avoiding electrical fires should be something considered at all points of a building or electrical installations life; at the design phase, while being built/installed, during use and maintenance and also, often overlooked, during a change of use that may mean existing systems are no longer suitable.

Push switch

Part M Switches and Sockets

Since it’s introduction in 2004, Part M of the building regulations aims to make it easier for people with a disability to use and access buildings. You may have noticed that buildings now have ramps, wider doors, railings and more to allow easier access. Electrically, Part M is concerned with switches, sockets and other controls. The implementation of Part M will not only help people with disabilities, it can also aid the elderly, hard of hearing or visually impaired. Primarily, it’s focus is on commercial buildings with some slight differences between dwellings & non-dwellings.

Part M contrasting colours

Part M Socket
Part M socket with green contrast switches for use on a dark wall/background

Part M states that to aid visually impaired people, the colour of electrical accessories should contrast the wall so that they can be easily identified. On top of this, the actual switches on the faceplates should further contrast so they stand out. If you’re using all white switches and sockets on white or magnolia walls then you’re not compliant.

Rocker switch positioning

If you have a look at most standard double sockets, the two switches are often arranged next to each other in the middle of the socket. To people with limited dexterity or the visually impaired, it can be hard to differentiate between the two. Part M double sockets have the switches arranged at each side of the faceplate, aiding ease of use. These are known as ‘outboard rockers’.

Positioning on the wall

Part M outlines recommended outlet positions for items such as light switches, sockets, TV outlets and other controls such as thermostats. The exact end users should be taken into consideration for this, as wheelchair users would require lower light switch positions and possibly higher socket positions than other users.

Wide switches

Part M Light Switch
Wide switch for users with limited dexterity or visually impaired people
Rather than using normal sized light switches, to help visually impaired or users with limited dexterity, special wide switches can be fitted to make the job of turning lights on & off much easier.

Locating plug sockets

Locating plug sockets
Locating plug socket with V groove to allow easy location of the earth pin. Available in Part M dark grey with white switch, all white and in single and double configurations.

Some plug sockets are designed with a special V shape that allows the earth pin of the plug to be easily located & let down to the correct hole. If you’ve ever tried to plug an appliance in behind a piece of furniture you’ll know how difficult this can be – this is what visually impaired people go through on a daily basis. These sockets can also help people who suffer from hand tremors, or just for sockets that are going to be hidden behind wardrobes, racking, shelving or other large pieces of furniture that aren’t easily moveable.

Applications

All commercial or industrial buildings, with particular focus on public buildings and the healthcare sector.

Give us a call

For a free, non-obligation quote, get in touch to book an initial site survey.

0330 223 16 55

Lines are open during office hours, Mon-Fri 08:30-17:00. Out of hours, leave us a voicemail and we’ll get back to you, or email us here.

Find out more about Part M and your obligations by downloading the pdf documents from the Planning Portal here.

Hotel Key Card Switches

Hotel Key Card Switches

Improve energy saving in your hotel, B&B or guesthouse

Hotel Key Card switches improve energy saving by working as the main switch in a hotel room. They’re easily operated by the guests, with lights and electric heating only becoming operational when the guest enters the relevant card into the switch. This saves energy by stopping the room being necessarily lit, heated or cooled when it isn’t occupied. When the card is removed, the switch can be set to let the power stay on for a pre-defined amount of time (from 10 seconds to 5 minutes) .

Glow in the dark

The switches come with a small LED indicator, allowing guests to easily find the switch in the dark, so no additional lighting is needed to be fitted. The switches are designed to fit standard key card sizes of 85.60 mm × 53.98 mm, which is the same as a credit or debit card.

Switching ability

The switches are designed to switch up to a 6 amp inductive load or a 10 amp resistive load, meaning that they can be retro-fitted to nearly all rooms with ease. Larger loads such as air-con systems can also be controlled via the use of a contactor.

Looking the part

The switches come in a range of finishes, meaning that it won’t look out of place with your existing faceplates. Styles include white, chrome, stainless steel, brushed steel, polished brass, matt black, black nickel and more. With access to the full range of light switches, power and media sockets from the Click range, if you wanted to add these as part of a full refurbishment we can make sure everything matches perfectly.

How much will I save using hotel key card switches?

This really depends on your occupancy rate. The average hotel room has a 65% occupancy rate & of that, the guest is in the room for around 40% of the time. If you are currently heating, cooling, or lighting the room for the large periods of time nobody is in it, then you should see savings of more than the cost of installation.

Applications

Hotels, guesthouses, serviced apartments, bed & breakfasts, offices

Give us a call

For a free, non-obligation quote, get in touch to book an initial site survey.

0330 223 16 55

Lines are open during office hours, Mon-Fri 08:30-17:00. Out of hours, leave us a voicemail and we’ll get back to you, or email us here.

Get a Quote