The making of FP200 Gold

It is 9am Monday morning and we arrive at the Prysmian factory in Bishopstoke near Eastleigh, in Hampshire. This 46-acre manufacturing site first opened in 1967 and is now the home of FP cable, as well as the world-renowned fire test lab. We are here to meet the engineering experts involved in the making of FP200 Gold – their most famous fire resistant cable and find out how these special cables are made.  

Our first stop is at the copper rod. The engineers tell us the start of any cable is the electrical conductor, and here we see the copper rod taken from the reel and drawn down to the right size. It can be drawn down to a wide range of wire diameters depending on which final conductor size is required. The copper resistance and elongation are measured, recorded, and verified according to British Standards. This is to ensure the copper wire meets the criteria.

Following these initial tests, we come to the insulation line. This is where the Prysmian composite insulation Insudite is applied. Insudite has been specially developed by Prysmian for its range of FP cables and is formulated to provide the best combination of fire resistance, electrical performance, and physical strength. Insudite is tough, durable, and highly damage resistant – which makes it ideal for all installations. In particular, those where there is the potential for third party damage to the cable after first fix. Prysmian conducts its own compound development, especially for fire resistant and low smoke materials.

At this stage, each of the cable components undergo further testing. During these tests, engineers look at a variety of elements including potential imperfections (such as holes caused during extrusion), check the insulation performance, and measure the dimensions. Checking dimensions is important as there is a specification to meet. For efficiency, Prysmian strives to meet the minimum insulation thickness. Prysmian control increasingly fine tolerances so the customer receives the high quality, reliable cable they expect. Concentricity of the conductor within the insulation is key to achieving the best material efficiency.

Following the success of these tests, we move on to the next line where the components will be assembled to form the cable. The engineers use a tandem process, which makes the assembly extremely efficient. The insulated cores are fed directly to the sheathing line and the uninsulated circuit protective conductor (CPC) is combined. They are wrapped together in a SZ formation. A longitudinal aluminium tape is then applied and formed around the cable components, which was our patented construction for 21 years. We discovered that it was invented even before the British Standard specification was written! It then goes through the extruder head for final sheathing.

The compounds used in the sheath are also Prysmian compounds. FP200 Gold was originally a PVC cable in the late seventies, but as the regulations changed, we developed more new materials, and we now use Low Smoke Zero Halogen (LSOH) sheathing. The main driver towards LSOH products was the tragic Kings Cross London Underground fire in 1987. LSOH cables give very little smoke, produce no hydrogen chloride gas in a fire but especially reduce the spread of flame, so they are specified for public areas.

The complete cable has now formed and is undergoing further tests. These are the same as the tests conducted during the insulation stage. This is to confirm that the cable has not been corrupted during the manufacturing stages. We now see the marking applied to the cable. Here, specific details describing what the cable is, its size, brand, etc are embossed or indented on the outer sheath. Engineers tell us this is far less messy than printing the details and confirm that the cable marking and manufacturing happen at the same time!

The cable is now ready for its final checks. The whole cable is electrically tested to the relevant British Standard. This is to ensure the cable is as expected and is of the highest quality.

We now come to the final leg of the cable’s journey – the coiling room. Here, the large manufacturing drums are cut and coiled onto reels ready to be shipped to the wholesaler.

However, for another batch of FP200 Gold, the day is not over yet. A sample is being taken to the Fire Test Lab. This is where Prysmian test for fire resistance. Over 1,500 fire tests are conducted here every year to check existing cables and new developments. Prysmian uses the fire test lab for research and development to get the most reliable and high-performance materials for its cables. The sample will undergo at least five different tests including smoke, acid gas, and flame propagation.

Samples are also sent to BASEC and LPCB, according to the routine testing schedule in the British Standard. Prysmian FP cables are subjected to a minimum of eight tests a year this way.

It is now the end of the day, and we visit the warehouse where we see stacks of FP200 Gold reels ready to leave the factory.

Prysmian has been researching and developing high-quality, efficient fire performance cables for decades, making it a trusted brand for specifiers. Find out more about Prysmian FP cables: https://uk.prysmiangroup.com/markets/trade-and-installers/fire-performance-cables.