34.5KV XLPE cables for Low Voltage Application

[Askarel27]

Contractor has a 34.5kV 1C x 300sqmm Cu/XLPE cable in their warehouse and suggested to used it in a 600V/1kV application. Is this possible?

 

[nkn5]

Its an overkill. but yes. you can use if you can gland and terminate it properly.

 

[dpc]

Sounds like a massive PITA, but permitted by the laws of physics. Amps are amps. Local codes could be another matter.

 

[davidbeach]

You do realize, don't you, that you'll be using 34.5kV splices and terminations since the 600V class fittings aren't listed for use with 34.5kV cable?

 

[waross]

Termination lugs are rated for applied voltage, not cable rated voltage. All the termination lug will see is the 600 Volts and bare copper.
If the cable was to be used at a higher voltage where stress cones were required, then you would probably have to use the 34.5 terminating kits due to the physical size of the cable and approvals.
Still, check with the local inspector. His opinion is the only opinion that matters!

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[squeeky]

Sell the HV cable and use the money to buy the correct one. Compromises will work but may have long term challenges. The correct cable should be lighter, thus the support structures and retaining systems can be smaller and save more money. Terminations can be .LV but what about the glands? You don't say if there is armouring or earthing conductors. More challenges. My recommendation is to use the correct material.

 

[dpc]

To be honest, if I were the local inspector, I probably would find a reason to red tag this. Too much potential for future confusion. NEC requires work to be done in a "neat and workmanlike manner". I think this installation would be a cluster and fail that requirement. There are also requirements that equipment and material be properly installed in accordance with their intended use.

 

[7anoter4]

Another issue it will be shield grounding and the build-up voltage-this depends on the current flowing through and not on voltage. If both ends would be grounded a derating factor could be required.

 

[Mbrooke]

Go for it. Other than 20 times the labor and more expensive splices it is possible to do. I have seen 4.8kv circuits reused like this since the cable was still good (5kv rated) but it would not make sense to pull it out an add new wire.

Just as a note, label, label, and more label whats going on as to eliminate a mix up.