EMC squared

From 20 July 2007, all fixed installations must comply with the essential requirements of the Electromagnetic Compatibility (EMC) Directive, which was introduced to ensure that installations do not interfere with other equipment, in particular radio and telecommunications equipment.

The directive aims to prevent instances of interference on systems such as air traffic control, essential healthcare services, data services or audio visual services, as the consequences of interference can sometimes be disastrous, even sometimes a matter of life and death.

For example, there have been cases recorded where hospital equipment has malfunctioned as a result of interference from nearby installations.

Who and what is affected?

The directive covers all commercial and industrial sites, including national infrastructure such as electrical, telecommunications, data, road and railway networks, as well as m&e installations within buildings, not just in the UK but also throughout Europe.

As a minimum, compliance will normally involve assessing the electromagnetic environment to ensure that the EMC elements of the equipment are appropriate, and following the equipment supplier’s instructions for EMC-compliant installation, operation and maintenance.

For more complex installations, simply using CE-marked equipment is not sufficient, with contractors being required to use good EMC engineering practices throughout.

This responsibility does not lie solely with the contractor but also with the client – the owner of the fixed installation – requesting the work. The owner can nominate someone else to be the responsible person for the installation, and this can be the contractor.

Get agreement from the client to pay any additional costs incurred as a result of these practices being carried out

However, recompense for being the responsible person will need to be taken into account.

Contractors therefore need to fully understand the new directive and what it means for them, as any failure to do so could result in additional work, along with complicated contractual and cost implications.

The new regulations now incorporate fixed installations and mean that the designers and contractors must ensure they have applied the best engineering practices within their installation.

This can mean additional expense for both new installations and modifications to existing ones.

Consequently, the ECA is concerned that some clients will be keen to offload the responsibility for EMC and its documentation onto contractors. The ECA advises its members to clarify such areas of responsibility before commencing work in order to avoid any future contractual disputes.

Get it in writing

All installations must be appointed with a responsible person, who will control the configuration of the installation and keep all EMC documentation available for inspection throughout the duration of the installation’s operational life.

The ECA strongly recommends that contractors obtain mutually acceptable responses in writing at the earliest possible opportunity to:

The ECA strongly recommends contractors obtain mutually acceptable responses in writing at the earliest possible opportunity to establish who is the named ‘responsible person’

• establish who is the named ‘responsible person’ for the project or fixed installation;
• gain clarification on which of the good EMC practices the contractor is being expected to employ and the resulting documentation required by the client;
• get agreement from the client to pay any additional costs incurred as a result of these practices being carried out.

Identify problems early

The ECA also advises members to start by identifying any interference problems that could happen to their designs, so that they can be dealt with in advance as part of the normal design specification process.

The proper layout and routeing of cables can significantly contribute to the good EMC of an installation, so this should be taken into careful consideration during the cable specification and/or the interface design stage of the project or installation.

The later in the design cycle that incorporating EMC is left, the harder and more costly it becomes to implement.

Consequently, incorporating EMC requirements into the design from the outset will save time and money, reduce returns and warranty costs, and will reduce the possibility of liability claims.

In essence, to avoid difficulties, contractors should make sure that their skill-sets are regularly updated in order to cope with the increasing complexity surrounding the equipment they are required to install.

The new version of the EMC Directive places increased responsibility on the industry, and failure to comply could result in prosecution.

Thus it is imperative that electrical installers know exactly what is expected of them and how they should manage their contracts to reflect and incorporate these added demands.