Cable Shield Type

[gordonl]

I'm ordering some 35 & 15kV cable, and I've gnerally required wire shield in the past to acheive the required current and time rating for clearing ground faults on my system.

A manufacture has proposed a "heavy" tape shield this time around, which meets the above requirement.

Does anybody have any info on the characteristics of a tape versus wire shield? I'm wondering if there are any mechanical advantages to one over the other.

 

[SphincterBoy]

GordonL, make certain you run a separate (full) copper neutral conductor near or in the same conduit or tray!

It is probably best if this separate neutral conductor is
insulated, to prevent corrosion in wet areas.

The tape shield cables do no handle fault current as well
as the stranded neutral types, necessitating the separate neutral conductor.

I really don't know the advantage(s) of using the tape
shield over the stranded neutral types.

Also, try to use EPR insulation.........based on years of
experience.

 

[gordonl]

I'm installing on a three phase, three wire, resistively grounded system. There will be a seperate bonding conductor installed, but not full capacity.

 

[busbar]

Some Info at:

http://www.kerite.com/

PDF format /sections:
Technical Data / Application Support technical_data_application_support.pdf
Installation Data / Installation Support installation_data_installation_support.pdf
Also

http://www.kerite.com/catalog/catalogfiles/ground_methods_power.htm

http://www.okonite.com/engineering/index.html

Shielding Currents

http://www.okonite.com/engineering/shielding.html

Shielding Discussion

http://www.okonite.com/engineering/shielding-currents.html

http://www.pirelli.com/en_42//cables_systems/catalog/cable_category.jhtml?itemid=900006

 

[RJF]

I've used a lot of tape shielded 5 and 15 KV cable in resistance grounded MV systems - they work fine as long as the tape is heavy enough to handle the ground fault current magnitude for the time it takes to clear the fault. Kerite, Okonite, Pirelli etc should all be able to provide their cable shield ratings. I have used some cables with wire shielding - seems to work ok with one excpetion. We had some of this cable going to 4.16 KV motors where the cables had to pass through a conduit seal. The sealing material pressed on the cable and caused the wires to migrate inward which eventually resulted in a failure. As in any shielded cable installation it is important to watch the bending radius and to properly terminate the cables.

 

[stevenal]

I believe termination is a little more involved. Terminations will require a tape shield adapter.