Automotive Electromagnetic Compatibility


Automotive electromagnetic compatibility is no longer regulated by European directives and instead is now legislated for by UNECE Regulation 10.

UNECE is the United Nations Economic Commission for Europe which is the body which has responsibility for implementing global trade agreements within Europe. Car manufacturing is now a global business and so the common requirements and standards go much wider even than the European Economic Area.

UNECE Regulation 10 requires manufacturers to gain type approval for all vehicles, electronic sub assemblies, components and separate technical units. Products that have direct control of the vehicles must not emit EMC emissions above the limits and must be immune to interference levels stated in the Regulation. Products without direct control only have to meet the emission requirements. The Regulation contains 3 groups of tests, narrow band emissions, broad band emissions and immunity tests, and their acceptance levels. Certain types of equipment are exempt from certain tests. Equipment for caravans and motor homes that operate when the vehicle is in use are included, but those that only operate when the vehicle is parked or are powered independently are excluded.

The Regulation is enforced by a different body in each member state. In the UK, the responsible body is the Vehicle Certification Agency (VCA), which is an agency of the Department for Transport. The VCA practices worst case selection prior to testing. Testing must be conducted by an authorized lab or be witnessed by the VCA, for example if the manufacturer has their own test facility. VCA assessors will also examine quality control systems. Approved products should carry an 'e-mark' accompanied by a number which identifies the Member State that granted the type approval.

:!: related to the Electromagnetic Compatibility Directive - click here to download a flowchart to help you identify which directive applies.

History and Purpose

Regulation 10 replaced The Automotive Electromagnetic Compatibility Directive 2004/104/EC (AEMCD) in November 2014. The AEMCD was one of the Article 100a directives which are intended to promote free trade throughout the European Union and the wider EEA.

Prior to enactment of the AEMCD, electrical equipment intended for use in motor vehicles was covered by the EMC Directive. However, the application of the EMC Directive to vehicles is complicated by a number of other pre-existing directives and so an anomalous situation where components and STUs were CE marked but the complete vehicle was not was common.

More significantly, the Electromagnetic Compatibility Directive is not primarily concerned with safety. The automotive industry was concerned that neither the standards nor the attestation procedures under the EMC Directive were adequate to ensure safe operation in vehicles where compatibility with (for instance) engine management and braking systems are critical for the safety of passengers.

On the basis of these concerns, the industry successfully lobbied the Commission to introduce new measures which removed components and sub-systems for road vehicle applications from the scope of the EMC directive and introduce a new single market regime which allows for different standards and a stricter attestation procedure.


The Regulation requires manufacturers to gain type approval for all vehicles and electronic sub assemblies (ESA’s).

This means that any device, or a part of the vehicle (whether it is an original part or an after market part) needs to be approved before it can be sold.

The Regulation contains a flow chart which helps to identify ESA's within its scope. Entirely passive items such as spark plugs, cables and passive antennae are excluded, as is any equipment which only operates when the vehicle is immobilised (i.e. when the handbrake is on). Items which do not connect to the vehicle wiring is generally also excluded, as are items intended for connection via standard interface which is itself already approved.

The Regulation also covers 'Rechargeable Electric Energy Storage Systems' (REESS) which are charging systems intended to provide energy for electric propulsion of the vehicle.


In essence, the requirements of the Regulation are very simple - it states that products that have direct control of the vehicle must not emit electromagnetic emissions above the limits set out in the Regulation and that products must be immune to the interference levels stated in the Regulation.

Products that have no effect on the direct control of the vehicle are require only to meet the emissions requirements.


In the UK, the enforcing authority is the Vehicle Certification Agency (VCA) which is an agency of the Department for Transport. Each EU member state has their own body responsible for enforcing the Regulation but the general structure of testing and approval is the same.

Complying with the Regulation

The EMC tests in are separated into three groups;

  • Narrow Band emissions
  • Broad Band emissions
  • Immunity tests

Definitions of the levels above which emissions are defined as unwanted or below which pollution and noise are accepted are specified in the Regulation. (An academic point, but one worthy of note nonetheless, is that this approach is different from that of the CE marking directives where the requirements are contained in standards rather than the Regulation itself).

There are exemptions from some of the tests for certain types of equipment:

  1. If the equipment does not have a electronic oscillator with an operating frequency greater than 9 kHz, it is considered to comply with the narrow band emission requirements without further testing.
  2. Vehicles which do not have electrical or electronic systems or ESAs involved in the direct control of the vehicle do not require immunity testing.
  3. ESAs which are not involved in the direct control of the vehicle do not need immunity testing.
The Approval Process

Application The manufacturer should apply to the VCA for the work to be done. If an independent test house is to be used then contact with the test house should be made direct, but a letter to the VCA should still be sent, stating which test house is to be used. (Test houses designated as ‘Technical Services’ can handle this aspect of the approval on behalf of clients so as to provide a ‘one stop shop’ service.)

Worst case selection The VCA practices worst case selection prior to testing in order to reduce the amount of testing needed across the range of a product types. A meeting should be held between the VCA (or the Technical Service who will act as a proxy for the VCA) and the manufacturer in order to consider the products to be tested, the tests to be carried out, and the date and venue for the testing.

Testing The VCA does not have its own EMC test facilities. Instead, they have accredited many laboratories both in the UK and abroad. A full list can be found on the VCA web site.

Organisations that are authorised as Technical Services can handle the whole process for the manufacturer. They will give the manufacturer a price for the complete test including the VCA fees for the issue of the approval certificate.

Tests carried out at laboratories that are not Technical Services must be witnessed by the VCA.

If the manufacturer wants the VCA to act as the Technical Service, they can witness the test work being carried out at any of the laboratories listed. The manufacturer takes out a job number with the VCA and will be responsible for making the test booking with the test laboratory, paying the test laboratory and paying VCA for witnessing the test and issuing the approval certificate.

These arrangements allow the manufacturer to choose the test house that they want to use and then to arrange with them for relevant reports and information documents to be sent to the VCA. The VCA then issue the approval certificate and document package.

If a manufacturer has their own EMC test facilities then the VCA can witness tests on site, without the involvement of any other test house. This will require a formal appraisal of the manufacturer’s test facility by the VCA.

Conformity of production

Type approval requires the testing of a sample and inspection of the documentation for the technical specification. It also requires conformity of production - confirmation that the manufacturer can consistently produce products to the approved specification.

To do this the VCA quality assessors will examine the quality systems in place in the factory. The approach follows established quality system principles as in ISO 9002. Certification to ISO 9002 will normally be accepted in place of factory assessments, though control plans dealing with issues specific to type approval activities may be needed in addition.

Marking requirement, the "e mark"

The Regulation has a different approval mark from the CE mark directives. Instead of the CE logo, products approved to the Regulation should carry the ‘e’ mark. This mark consists of a rectangle surrounding the letter 'e' followed by the distinguishing number of the Member State which has granted type-approval.

The marking must also include, in the vicinity of the rectangle, the four-digit sequential number, referred to as 'base approval number', preceded by two figures indicating the sequence number assigned to the most recent major technical amendment to the Regulation. (The test house or Technical Service will advise the manufacturer of this number during the approval process.)

If an electrical or electronic system has been approved as part of a whole vehicle test then that system does not require “e” marking. The same system sold as a spare part will also not require “e” marking. It is, however, recommended that the packaging bears the “e” mark.

Non original-fit equipment e.g. aftermarket products, and ‘pattern’ replacement parts, will need to be “e” marked.

ESAs will also require “e” marking. This includes in-car entertainment systems, cigarette lighter socket connected electrical devices (including mobile phone chargers) and after-market alarm systems.

The EEC type-approval mark must be affixed to the main part of the equipment in such a way as to be clearly legible and indelible.

Machinery Directive and Automotive EMC

The Machinery Directive sets out essential health and safety requirements for “machinery”.

Products covered by the Machinery Directive must meet the requirements of the relevant Directives and be ‘CE’ marked. The generic EMC Directive generally applies to products covered by the Machinery Directive.

However, machinery intended to be fitted to a road vehicle can be considered to be a vehicle component, therefore if the vehicle falls within the scope of Regulation 10, the machinery fitted to that vehicle may also fall within the scope and consequently be governed by the Regulation.

In certain cases, e.g. non-road mobile machines such as construction or agricultural machines, the whole vehicle will have been designed as a piece of mobile machinery. Such vehicles fall outside the scope of the Regulation and hence will have to comply with the 'normal' EMC Directive.

Equipment in caravans and motor homes

Equipment that is intended for vehicles and operates when the vehicle is in use should comply with Regulation 10. Equipment which is powered independently from the vehicle supply and which can only be used when the vehicle is parked should comply with the EMC Directive.


The bad news for manufacturers of products within the scope of the Regulation is that they need to have every piece of apparatus approved by the VCA and this means having it tested. On the other hand, if the product can work independently from the vehicle, then it may also come under the EMC Directive. Often, it will be possible to combine the testing and save some of the cost.

Most manufacturers of automotive electrical products have little to fear from the Regulation and type approval should be straightforward so long as they take a logical approach to the requirements and maintain accurate records.

The Vehicle Certification Agency are the UK Government agency which enforces the Regulation. Their website includes several useful documents including a list of test houses and Technical Services. s

Further advice

As with all directives and regulations, the actual requirements for any piece of equipment are complex and dependent on not only the design but also the type of user, the intended use and sometimes even what is claimed in the instructions or sales literature.

Conformance are not an EMC test laboratory, nor do we specialise in EMC related design. We do, however, know several people who are specialists and we're happy to recommend reputable test laboratories to clients where testing is actually necessary.

We also have extensive experience of applying the requirements of the Regulation and CE marking equipment as part of a package where (as is usually the case) Regulation 10 is only one of several requirements which have to be considered.

For further advice specific to your products, please contact us at Conformance and we will be pleased to discuss your needs.

autoemc.txt · Last modified: 2016/11/08 15:59 by Nick Williams
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