With so many cable materials, sizes, applications and specifications in existence around the world, controlling and managing standards is complex. In this section we aim to make understanding them easier, by summarising the main standards, who produces them, why and what they do:
British Standards – BS https://www.bsigroup.com/en-GB/
The British Standard (BS) 7671 is the national standard for electrical wiring and installation safety in the UK. It’s also known as the IET Wiring Regulations, currently on its 18th Edition. The regulations are produced jointly by the British Standards Institution (BSI) and the Institution of Engineering and Technology (IET). They are designed to act as guidance for electrical systems designers, electrical contractors and electrical engineers, amongst others. The aim is to protect people and property from electrical hazards, like fires and shocks and ensure that electrical work is safe and effective.
BS 7671 covers the design, installation, and maintenance of electrical systems, the selection and installation of electrical wiring, the protection of electrical systems from damage, testing and inspection of electrical systems, and requirements for earthing and bonding.
A copy of BS7671 can be sourced from the BSI website here https://knowledge.bsigroup.com/search?query=BS7671
European Standards – CENELEC https://www.cencenelec.eu/
CENELEC is the European Committee for Electrotechnical Standardisation, an association that brings together the National Electrotechnical Committees of 34 European countries, which are:
All 27 European Union (EU) countries, the UK, Iceland, Norway, Switzerland, Serbia, Turkey and North Macedonia.
CENELEC also has cooperation agreements with Canada, China, Japan, South Korea, Russia and an informal agreement with the USA.
CENELEC committees develop European Standards for cables, insulated conductors, flexible cords and associated accessories.
For details of how to source European Standards, visit the CENELEC website here
https://www.cencenelec.eu/european-standardization/european-standards/obtaining-european-standards/
International Standards – IEC https://iec.ch/
The International Electrotechnical Commission (IEC) controls the publication of cables standards worldwide, which are recognised, but not exclusively adopted by a majority of countries. Many countries retain their own national cable standards as well.
Full affiliate members of the IEC include:
Algeria, Argentina, Australia, Austria, Belarus, Belgium, Brazil, Bulgaria, Canada, Chile, China, Columbia, Croatia, Czech Republic, Denmark, Egypt, Finland, France, Germany, Greece, Hungary, India, Indonesia, Iran, Iraq, Ireland, Israel, Italy, Japan, Korea Republic of (South Korea), Libya, Luxembourg, Malaysia, Mexico, Netherlands, New Zealand, Norway, Oman, Pakistan, Philippines, Poland, Portugal, Qatar, Romania, Russian Federation, Saudi Arabia, Serbia, Singapore, Slovakia, Slovenia, South Africa, Spain, Sweden, Switzerland, Thailand, Turkey, Ukraine, United Arab Emirates, United Kingdom, United States of America.
In addition, there are 22 associate members:
Albania, Bahrain, Bosnia & Herzogovina, Cuba, Cyprus, Democratic People’s Republic of Korea (North Korea), Estonia, Georgia, Iceland, Jordan, Kazakhstan, Kenya, Latvia, Lithuania, Malta, Moldova, Montenegro, Morocco, Nigeria, Sri Lanka, The Former Yugoslav Republic of Macedonia, Tunisia and Vietnam.
IEC standards cover low voltage, medium voltage and high voltage power cables and cable accessories for a wide range of applications.
There is growing harmonisation between IEC and CENELEC standards. Specifying IEC cables may allow for improved access to cable types (for instance, in the event of urgent maintenance it may be challenging to procure a niche national standard cable but an IEC cable providing comparable performance may be suitable).
In many cases national standards are more stringent than IEC standards, so when using IEC standard cables they must also comply with national wiring regulations.
IEC International Standards can be sourced from the IEC website here:
https://webstore.iec.ch/en/products/?p=1&f=eyJkYXRlUmFuZ2VzIjp7fSwidGVybXMiOnsidHlwZSI6eyIxIjpbIklTIl19fSwidmFsaWRPbmx5Ijp0cnVlLCJwdWJsaWNhdGlvbklkcyI6bnVsbCwic2hvd1RyZiI6dHJ1ZSwiZGlzcGxheU1vZGUiOiJncmlkIn0=
Fire performance tests
The purpose of fire performance tests is to verify that a cable will continue to maintain electrical functionality for a certain period of time in simulated fire conditions. Such cables are used to provide power to fire prevention and control systems. There are several different fire performance tests for cables:
BS EN 50200 – Fire Performance standard – for small cables
BS EN 50200 – is the method of test for resistance to fire of unprotected small cables for use in emergency circuits. The test includes direct flame at a temperature of 842°C with mechanical shock to the back board on which the test cables are mounted. There is an additional separate test included in Annex E covering a water, fire and mechanical shock element. Results for 30, 60 and 120 minutes fire resistance are recorded.
BS6387 – British Fire Performance test – for medium-sized cables
BS6387 covers cables with a diameter of up to 20mm. The standard describes three tests which the cable must pass – C, W and Z. The tests are conducted on a special fire test rig and the cable is energised to 600V. The cable’s electrical continuity is indicated by a series of light bulbs connected via fuses. A failure is indicated by the fuse blowing and the light failing on the bulbs.
BS8491 – Fire Performance standard – for larger cables
BS8491 is the British Standard test for cables with a diameter greater than 20mm.The test involves subjecting a cable to radiation via direct impingement, corresponding to a constant temperature attack of 842oC; to a direct mechanical impacts force of approximately 10N; and to direct application of a water jet simulating a firefighting water jet.
IEC 60331 – International Fire Performance standard
The International standard for Fire Performance tests is IEC 60331. It covers a number of individual test methods (Parts) for different cable types:
Part 1: Fire with shock at a temperature of at least 830°C for cables of rated voltage up to and including 0.6/1kV and with an overall diameter exceeding 20mm.
Part 2: Fire with shock at a temperature of at least 830°C for cables of rated voltage up to and including 0.6/1kV and with an overall diameter not exceeding 20mm.
Part 3: Fire with shock at a temperature of at least 830°C for cables of rated voltage up to and including 0.6/1kV tested in a metal enclosure.
Part 11: Apparatus – Fire only at a flame temperature of at least 750°C
Part 21: Procedures and requirements – Cables of rated voltage up to and including 0.6/1kV
Part 23: Procedures and requirements – Electric data cables
Part 25: Procedures and requirements – Optical fibre cables
Parts 21, 23 and 25 cover fire-only conditions at a flame temperature of at least 750 °C.
What voltages are used in different countries and why?
Most countries use two types of voltage. Residential voltage (called single phase in the UK) is designed to be enough to power appliances while still being safe to use. The second is called three-phase voltage, which is generally used in power transmission. It has higher voltage to power larger machines in industrial settings.
Electricity was pioneered from more than one source, which meant that voltages were not standardised from the outset. Consequently, different countries selected different voltages to best suit their needs, resulting in two main voltage ranges – 100-127V used in North America and parts of Asia and 220-240V, used in most of Europe and Australia.
