Protection/comms pilot cables in tunnels

[ItAintMe]

Does anyone have experience using XLPE insulated pilot cables, and if so, what sort of sheath materials have you used? I have a proposal to use fibreglass tapes under Fire resistant PVC in a tunnel, but this is pretty expensive. Is all this necessary? What about just FRPVC? We normally use HDPE sheaths, but want to avoid smoke generation and hopefully have something that is self extinguishing in the unlikely event of a fire in the tunnel.

 

[Elecme]

My experince also was in using HDPE sheath. Elecme

 

[wilber]

If you are wanting NOT to generate smoke in case of a fire, then don't use PVC.
Investigate UL 1685 Standard for cables. This standard defines cables that pass the standard vertical ladder flame tests and carry an "LS" limited smoke rating. They are usually less dangerous fumes in cable that pass this smoke rating.