What you need to know about meter tails

In recent years there have been an increasing number of reports of fires involving consumer units, sometimes caused by loose terminations at the consumer unit. As well as adhering to guidance and practical advice produced by Electrical Safety First and BEAMA on achieving safe and reliable connections, understanding key details about meter tails is essential. 

A spotlight on meter tails

Meter tails are typically designed and manufactured to British Standard BS 6004 which covers PVC insulated and PVC sheathed cables for voltages up to and including 300/500 V, for electric power and lighting. The most common meter tails by far used in domestic installations is 6181Y.

Traditional meter tails feature 7-strand conductors and are still used substantially. In modern installations, however, 6181Y 19-strand meter tails – sometimes called “flexi tails” – are increasingly used. The two cables have a blue sheath with blue insulation, and a brown sheath with brown insulation. The 7-strand tails both have a grey outer sheath, and one has brown insulation, and the other has blue insulation.

The Electrical Safety First/BEAMA guidance highlights that, during research carried out by Electrical Safety First, using 19-strand meter tails gave a more reliable connection than using the conventional 7-strand tails. As a result, the use of 19-strand cable is recommended to increase safety. 

Additionally, the same research revealed that flattening the strands of the conductor before terminating resulted in a reliable connection. Further advice on best practice can be found here.

The case for 19-strand meter tails

So, why do 19-strand conductors provide more reliable connections? These cables offer several benefits, including: 

1. Greater pliability

   They are less rigid than the 7-strand version, allowing for improved pliability.   

2. Improved reliability and safety in screwed connections 

   There is reduced mechanical stress at the connection points as the strands securely bend around the screw when they are installed. This provides more secure terminations.

3. Reduced risk of arcing 

   As distribution boards expand and contract between seasons (summer and winter e.g.), rigid cables can loosen and can lead to poor connections. This can result in issues inside the property such as flickering lights and increased risk of fire.

These benefits ensure 19-strand meter tails are more reliable in the long term. 

Are meter tails double insulated? 

A common misconception about meter tails is that they are double insulated, however, this is not technically correct. The 6181Y meter tail is PVC insulated, and PVC sheathed. This means it has an inner insulation layer for electrical protection and an outer sheath for physical protection – as defined in BS 6004. The sheath does not provide an additional layer of electrical insulation so, describing these cables as “double insulated” is incorrect.

Prysmian 6181Y 19 Strand

Immagine

Prysmian designs and manufactures 6181Y 19-strand. This low voltage single core cable features an insulated stranded copper conductor with an additional PVC sheath insulation for physical protection.    

Prysmian 6181Y 19-Strand is fully compliant with BS 6004 and has been tested to BS EN 60332-1-2, which assesses the vertical flame propagation of single electric or optical fibre cables.

Using CableApp

To confirm the correct cable size for a new installation, CableApp can help. CableApp is an easy-to-use cable calculator tool developed by Prysmian to help professional electricians find efficient and precise cable solutions for any project. 

CableApp is fully compliant with the latest wiring regulations, BS 7671 (18th Edition), so you can be sure your installations will be secure, reliable, safe, and compliant.

In short, using 6181Y 19-strand cables, manufactured in accordance with BS 6004, provides greater pliability, secure terminations and improved reliability compared to the 7-strand version. By selecting Prysmian high-quality meter tails and following best installation practices set out by Electrical Safety First and BEAMA, electricians can ensure safe, reliable and efficient electrical systems for their clients.