Electromagnetic advice for automotive manufacturers and importers

This advice is designed to provide basic guidance to traders. It is not a complete or authoritative statement of the law. Please note that some of the advice we provide to businesses is chargeable.

Advice for manufacturers and importers of after-market products.


This advice is intended to give advice on complying with the law to manufacturers and importers of electronic devices for use in motor cars such as CD players and data systems.

The Road Traffic Act prohibits the use on the road of cars fitted with after-market electric/electronic sub-assemblies (ESA) unless the ESA has undergone type approval in accordance with European Directive 95/54/EC and are marked with the 'e' mark and associated labelling.

It is also illegal to supply such parts if there is reasonable cause to believe they will be fitted to a car in circumstances that would lead to a breach of construction & use requirements.

What is an ESA (Electrical/electronic sub-assembly)?

Typical examples are in-car entertainment equipment such as radios or CD players, accessories such as mobile phone car-chargers and spare parts such as ABS modules. Also included are in-car radios and data transmission systems such as those used in taxis.

All new ESAs must comply with the requirements outlined in this factsheet. This does not affect existing ESAs already in use prior to 1st October 2002.

Which items need to be e-marked?

The following items need to be e-marked: 

  • as a general rule, ESAs intended for fitment to passenger cars must comply.
  • equipment which was not intended for fitting to a vehicle by the manufacturer, but nevertheless which is being installed in a vehicle by an organisation on a commercial basis. For example, a company installing computers in vehicles as a permanent fixture.
  • equipment that is marketed on the basis that it is suitable for installation in a vehicle. For example, a 'travel laptop' advertised as suitable for use in a car and perhaps provided with an adapter to enable use of 12v supply.
Which items do not need to be e-marked?

The following items do not need to be e-marked: 

  • equipment not 'intended for fitment to a vehicle', for example, a laptop computer or video camera, which is designed for domestic use. So a private person modifying or installing electronic equipment in their own vehicle would not be required to obtain type approval.
  • passive equipment. This means equipment that cannot emit or be affected by electromagnetic emissions. This includes spark plugs and 'passive' antennae.
  • equipment that can only be used while the vehicle is incapable of moving. This includes equipment such as a tyre inflator powered from the cigarette lighter. If the equipment is mains-powered equipment installed in a vehicle and intended to be powered by mains power or a generator, then it does not require approval because it cannot be used in the moving vehicle.
  • equipment not permanently fixed to the vehicle AND self-powered (can be removed without tools) if it does not use the vehicle power supply but has its own battery. For example, a handheld mobile phone.
  • equipment not permanently fixed to the vehicle and powered using the vehicle power supply, but connected by means of a separate interface that is approved to the requirements of the Automotive Directive. This interface unit could be an adapter or transformer, and would be tested with a representative piece of equipment connected to it. That means that an in-car charger for a mobile phone must be approved to the Directive but the mobile phone itself does not need approval. However it may require a CE mark according to other non-automotive legislation.
  • vehicle manufacturers' spare parts, identical to those fitted as original equipment on production vehicles are exempt if they were included in a vehicle that has already been type approved to the Automotive Directive. But pattern parts are not exempt.
  • spare parts intended for older passenger cars. Cars produced before 1 January 1996 may be retrofitted with non-compliant equipment. It is recommended that relevant spare parts should be labelled as unsuitable for newer cars, or labelled specifically for the cars they are intended for in order to reduce the likelihood of inappropriate supplies. 
  • 'one-off' equipment. The Automotive Directive is a type-approval Directive. This means that one item is tested as being representative of a particular 'type' of product, and further items manufactured in line with the approved 'type' may be sold without further testing. This does not cover the situation where one unique item is produced by a person not normally engaged in the business of manufacturing electronic equipment for sale. Such equipment does not require e-marking. Where a professional produces a one-off ESA, the individual circumstances would have to be considered. The professional installer would be advised to use approved components if possible or at the very least CE marked components.
  • equipment installed in their own vehicle by persons who are able to demonstrate competence (for example radio amateurs). However, equipment designed by a commercial producer for use by radio amateurs is not exempt.
  • ESAs intended ONLY for fitment to other types of vehicle (trucks or buses) do not have to comply in the UK but this may not be the case in other European Union countries. In such cases, the ESA may be refused sale or entry into service.
  • mobile machinery (for example mobile cranes, off-road construction plant) and equipment intended for fitment to motorcycles and agricultural tractors do not have to comply, although similar requirements are likely to be introduced for motorcycles in the future.
  • vehicles which are new or improved types constructed for tests or trials, or vehicles equipped with new or improved equipment, are exempt from certain aspects of the Construction and Use Regulations while they are being used for tests or trials. Therefore, prototype ESAs are not required to be E-marked.
  • you may have seen car components marked with an 'E' mark. This relates to a UN system of approval and in relation to EMC compliance, only applies to European counties which are not part of the EU. Inside the EU it is the 'e' mark which applies.

The Regulations apply to equipment intended for installation in vehicles but do not address the question of how that equipment is installed. Installers should be aware whether the type of equipment they are installing needs to be e-marked. Whether or not the equipment is required to be e-marked, it needs to be installed in accordance with equipment and vehicle manufacturer recommendations and any relevant Codes of Practice, so that vehicle electronic systems are not put at risk. Specialist advice should be sought if there is any doubt about this.


A compliant product is required to be e-marked. Unlike CE marking, which can be self-certified, to obtain an e-mark a product must be witness-tested by a Technical Service appointed by the VCA (Vehicle Certification Agency), which is an Executive Agency of the Department for Transport. The VCA will issue the approval certificate and approval number, which must be marked on the product. As these requirements apply across Europe, manufacturers and importers can alternatively approach type approval bodies in other European Member States.

Who is affected?

Manufacturers of electrical or electronic parts or aftermarket accessories intended for fitment to vehicles after first registration, installers of these items in vehicles, operators of vehicle fleets and purchasers of these items are all affected.

Manufacturers of equipment should ensure all relevant equipment they produce complies.

Installers of equipment should check whether the type of equipment they are installing needs to be e-marked.

Purchasers of equipment should ensure any equipment they purchase is e-marked, if necessary.

How do I obtain approval?

The UK Approval Authority for automotive approvals is the Vehicle Certification Agency (VCA) based in Bristol. However, they do not have EMC test facilities, therefore testing may either be performed by a VCA authorised test house (Technical Service) or the VCA will witness the testing at an acceptable laboratory of your choice.


'Legacy' equipment means equipment which was second-hand on 1 October 2002 or sold as new before that date. Often this old equipment is transferred to new vehicles, such as sirens and light bars used by the emergency services.

Legacy equipment does not need to be e-marked and may be installed in any vehicle, new or old, after 1 October 2002. However, the installer must still exercise due care to ensure the installation does not compromise road safety.

Any new equipment sold after 1 October 2002, of a 'type' that was already on sale before 1 October 2002, is NOT legacy equipment however and must be approved (if applicable).

Enforcement will be carried out by local Trading Standards Officers, at the point of sale, and by the police on vehicles in use.

A vehicle user found operating with non-complaint equipment would technically be invalidating his insurance and could be prosecuted in the event of an accident.

The supplier of non-compliant equipment or a workshop which fitted non-compliant equipment could be prosecuted.

Future changes

A new Automotive EMC Directive (2004/104/EC) has now been published. New vehicles and components must comply with the new Directive from 1st July 2006 (for manufacturers) and 1st July 2009 (for retailers). e-marking will not be required under the new Directive for non-immunity related aftermarket accessories, but manufacturers will need to self-certify compliance with the requirements for emissions and conducted transients and obtain a certificate from the automotive authorities certifying that their products are not related to immunity and do not need type approval.