strand

Hello All,

would anyone know anything about water blocked strand or stranding,

many thanks,

Dave.

Hello David,

Water blocked strand is a tricky subject so I will limit this answer to larger conductor, XLPE type products.

Firstly the water blocking media must be a semiconducting, semi-liquid, sticky, rubbery, mastic like, material and it must be applied as individual layers over each of the internal conductor layers, including the king or center wire.

The water blocking mastic is applied at conventional rigid stranders. There are two methods of applying the mastic; flooding and extrusion. I much prefer extrusion as one can precisely meter the amount of the mastic applied. Much care must be taken so as not to overfill the interstitial spaces inside the conductor.

The outer layer must have a heavily overlapped, helical, moisture swellable, semi-conducting tape applied with the direction of pitch the same as that for your the outer conductor layer. The reason for all this is the fact that when a filled, stranded conductor is wrapped around a capstan, its circular profile becomes somewhat oval and the mastic will come out and get on to the capstans. This obviously destroys the extrusion process.

Lots to think about.

Hello Peter,

Thank you for the information, very interesting and yes plenty to think about,

Kind regards,

Dave.