BT Laboratories open their doors to commercial EMC testing

Introduction

The EMC Engineering Group has grown from two engineers in 1985 to 14 at the present time. They are involved not only in testing products, but developing new methods, and have a major involvement in international standards work. As BT no longer manufactures products, the work of the laboratory has now evolved into assessing integrated systems offered by the company as turnkey solutions.

Latest Developments

BT has always performed some EMC testing for other companies, but in the past this has been largely for manufacturers supplying products to BT. The increased capacity has allowed BT Laboratories to offer testing more widely, to other manufacturers in the IT and telecommunications fields.

Services Available

A benefit for manufacturers using the laboratory is the wide experience and knowledge of the BT test engineers in these fields, particularly in the exercising of the equipment to maximise emissions and in understanding failure modes. Additionally, the capability of the laboratory, providing specialist test, exercising, and support equipment such as call senders, and artificial ears (to measure the level of breakthrough on audio circuits), means that the manufacturer has to bring less equipment with him to support the testing. Power supplies commonly used in telecommunications systems such as -48 V are readily available, as are single phase supplies at 230ÿV 50 Hz (and the three-phase equivalent) and 110 V 60 Hz.

Naturally, for an organisation dealing with equipment connected to long wires in exposed locations, lightning protection is an area of specialism, and testing can be performed to all the international requirements.

Competence and confidentiality are assured by the United Kingdom Accreditation Service's NAMAS accreditation. The laboratory is the only accredited EMC facility in East Anglia. In addition, the laboratory is registered with the FCC in the USA, and holds AUSTEL accreditation.

The laboratory prides itself on its comprehensive reports, and also its flexibility, so that if failures are found, the accredited testing can be stopped and investigations carried out into the cause of the failure. Solutions can be offered to fix the problems. Thus the laboratory offers not only "MoT" style testing for compliance to harmonised standards, but also a diagnostic service. The latter is of course not under NAMAS accreditation.

The need for site surveys of the electromagnetic ambient for proposed installations has been growing, and a dedicated site survey vehicle has been acquired. This is used to characterise the environment prior to equipment being installed, and can also be used to perform in situ emission measurements.

Further information is available from: Dave Standley, Senior EMC Engineer
Tel: 01473646053, or e-mail: