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TAPE SHIELD

TAPE SHIELD

TAPE SHIELD

(OP)
Can anyone tell me what the advantages are for using high voltage undergound cable with a tape shield?

RE: TAPE SHIELD

Are you wanting to know why medium voltage and higher cables are shielded or the advantages of a tape shield over a wire shield or Unishield?

RE: TAPE SHIELD

(OP)
The later........why tape shields are preferred vs. wire shields.

RE: TAPE SHIELD

For the voltages I work with (15KV and below) the method of shielding has not made any difference over the years.
The cable companies do, however, on their web sites tell you why their type is better.
Check out the following references:
Why tape is better:
http://www.southwire.com/processGetArticle.do?commonId=7d2e5f7f22eb4010VgnVCM1000002702a8c0____

Why Unishield is better:
http://www.generalcable.com/NR/rdonlyres/3822E679-352D-49AF-8431-C5D7DD408302/0/INS0042R0601.pdf


http://www.nexans.ca/egy/tecdoc/4.htm

RE: TAPE SHIELD

(OP)
Thanks TestBeforeTouch!

We are upgrading several substation underground feeders, and I remember some years back when the contractor installed tapeshield concentric neutral MV cables, and I never knew the reason why, other than we had to install a separate neutral conductor since the tapeshield cable does not handle fault current well.

I've often wondered if it was to suppress 60+ Hz noise from interfering with phone and/or cable lines which may lie in the same trench as the MV cable.

RE: TAPE SHIELD

Some of the differences between tape and concentric neutral shielding may be application derived:

1) Concentric neutral (either full or 1/3 ampacity) may be most commonly installed in utility distribution systems where single phase loads REQUIRE neutral capacity, URD= Underground Residential Distribution

2) It there is an overjacket (URO) over the concentric strand (which is often done to prevent corrosion of the concentric strands, depending on soil or conduit conditions) I believe it is a code  (NESC?) requirement to include another bare neutral/ground wire if the the cable is installed in joint trench with other voltage class systems.

3) there has been some customer reluctance to use corrogated strand shield, possibly the customer I am aware of had problems with the conductors coming out of the cable during installation.

4) Most industrial installations will not use the jacket as a common neutral (current carrying neutral sharing duty with ground wire) but will install a separate ground wire.

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