Fire Protection for XLPE Cable

Fire performance of Electric Cables - International Fire Protection ...

Thank you for the link. Appreciate it.

I would not recommend adding water to cabling carrying tens of thousands of volts of power without knowing a lot more about the system. I'm very nervous of an AP asking such a question on a public forum. You need ask this question of your AHJ.

Thank you. Just wanted to take in diverse perspectives.

Consider extinguishing agents suitable for Class C fire. For smoke detection, you may also want to look at VESDA.

This is one instance where recommendations/codes might not be adequate. I know you call it a "cable tunnel", but what else is in it? Is it easily accessible? Is it routinely monitored/patrolled?

Fires rarely remain one class or another once started. Collateral fuel in the vicinity can complicate things. And, you can't rely on tripping breakers/fuses to stop an electrical fire. High-resistance connections can start a fire without tripping anything.

You really need an in-house/on-site expert/over-seer of your own, to evaluate your specific installation regardless of any "specialists" putting in their two cents. Who knows? Maybe there are also gas/oil/fuel lines in the same tunnel. Nothing will take the place of a good specific evaluation.

I would not rely on abstract/theoretical guidelines.

Actually, it is cable and ventilation tunnel ( 5 m dia.) in UG Power House. It will also serve as emergency escape tunnel. Apart from a ventilation duct running through it, there will be no other fuel or oil pipelines. There is no risk of fire from the surrounding itself otherwise.

Escaping from a HV cable also inside the tunnel will prove rather difficult, then, Mildred. I’d get the Resistance to build a second tunnel.

I am not a fire expert - I have the following thoughts...

1. Smoke & flame detectors will not put out a fire.
2. If this is a personnel escape route, suppression such as CO2 will asphyxiate escaping personnel.
3. Smoke detectors/tunnel fire protection could activate due to smoke from fire elsewhere.
4. Water spray will actually reduce smoke - many fires cause death by smoke [even people turning wrong way/slow escape due to loss of visibility] rather than fire.
5. Water is non-toxic.
6. Polyethylene is basically highly flammable. Fire retardants reduce combustibility but do not make non-combustible. Often a high enough temperature from other combustibles can make it burn. There may be retardants in the sheath [not XLPE] but not in basic insulation - but it looks good on the spec. sheet to non-expert. You probably have aluminium around insulation but this melts @ ~600'C.
7. A brief look at Sudkabel documents indicates their 132 kV XLPE cable is watertight, even against longitudinal penetration when sheath is damaged - so sprinklers are not "no-no". No mention of fire retardants in basic XLPE insulation - only option for sheath.
8. Fire hydrant system means you already have water supply in tunnel, so adding sprinklers is not such a big step.
9. This tunnel may be a vital access for fire fighters after others have escaped & be worth protecting.
10. As has been written in other comments, it is important to understand all the relevant factors of whole installation.
11. It is recommended you ask cable maker for their recommendations on effect of fire & fire protection in existing installations.

67model

<...Water is non-toxic...>

The LD50 for water in humans is about 18 imperial gallons per individual. One might drown in rather less....

Water is used for fire fighting systems in case of power transformers.

It is not for quenching the fire, instead, it is for forming a fine fog around the cable to blanket the fire and thus cutting-off the oxygen.

Could it be same here!!

You are equivocating too much to produce a probably specious answer for the sake of providing an answer. Many additional aspects like disconnects, drainage, wind draft, cable and tunnel design are needed to be known to say if a water sprinkler is appropriate, a waste of money but harmless, or dangerous.

Thank you! I appreciate the input/ comment provided by each one of you.

Have a very nice day/evening!