20/12/2019
This article was co-athored by Dr John Ford, Technical Lead Mechanical/Electrical UK, Envista Forensics
The risk of electric shock or electrical fire has led to many instances of electrical goods being recalled by the manufacturer.
This article focuses on electrical consumer units (consumer units), sometimes still referred to as fuse boxes, which distribute the main electrical supply entering a property to individual circuits. As an integral part of any building requiring electricity, we consider some of the potential fire hazards and product liability risks that consumer units can pose.
Consumer units are made to exacting standards to meet legislative requirements and so it is important that they are installed by a qualified professional. They contain circuit breakers and earth leakage devices that detect fault currents and trip to protect the premises and its occupants from electrical overloads, electric shocks and electrical fires. As such, they contain numerous electrical connections which are screw terminals, where metal tubes are encased in an insulating block with a set screw at each end of each tube to hold and thus connect the conductors.
Each one of these connections represents a point where for various reasons loose connections can occur causing a high resistance and possibly arcing. This is when electrical current flows between two conductors separated by air whose insulation has broken down.
Some of these connections are made by the manufacturer of the consumer unit before supply, but many are made by the electrician who installs the consumer unit. From experience, loose connections can be because:
The most common effect of a high electrical resistance connection will be localised heating around the connection. On a high current circuit, even a small unwanted resistance (of the order of an ohm) can result in the dissipation of hundreds of watts of power at the joint. This will quickly damage the insulation of cable or the connection and can result in electrical arcing, burning and ultimately a fire.
In recent years, there have been several product recalls on miniature circuit breakers (MCBs) and residual current breakers with over-current (RCBOs) that are contained in consumer units, which have been implicated in consumer unit fires and/or relating to other safety concerns. However, it is reported that the estimated average success rate for electrical product recalls in the UK (i.e. products that are returned to the manufacturer) is currently only between 10% and 20%.
Electrical equipment is covered by its own sector-specific regulations as well as the General Product Safety Regulations (GPSRs). Under the GPSRs, a producer or distributor who is found to have placed an unsafe product on the market can face a fine of up to £20,000, up to 12 months' imprisonment, or both.
Manufacturers and retailers of consumer units have a responsibility to ensure that their products meet safety requirements. An action for breach of contract, for negligence or strict liability under the Consumer Protection Act 1987 (the CPA) can be brought for death, personal injury and private property damage caused as a result of the alleged product defect.
Hufford v Samsung Electronics (UK) Limited [2014] demonstrated the threshold that a claimant must reach to show that a product was defective under s.3 of the CPA. In this case, the claimant was able to show that the damaging fire began around the product in question, but could not prove that the product itself was the catalyst for that fire. The court deemed there was insufficient evidence to discharge the claimant's burden to show that the product was defective and found in favour of the defendant.
Manufacturers of consumer units must ensure their products meet the required safety standards and have effective product recall procedures in place should the need arise. Manufacturers should also provide clear instructions for instalment, maintenance and replacement by a qualified professional. Finally, consideration should be given to obtaining expert advice in the defence of a product liability claim, to examine whether the cause of any alleged damage was due to the product itself or potentially the electrician who installed it, or both, or perhaps some other unrelated cause.
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