Grounding balls into 34.5 kv switchgear

[Chad12]

I am a "by the book" power system service manager. I do not have an opinion on the proper way to perform electrical work, I follow established procedures and standards. I recently began a project, installing grounding balls into 34.5 kv switchgear to make grounding easier. I did the first three sets personally, then had a service tech take over. We are only able to do about three sets each outage. On the third outage, an engineer (EE) instructed the service tech to use aluminum foil (Reynolds wrap) at the cable termination, then do a standard 69kv tape over the top. I went mental. I know some of these "old school" tricks were used in the past, but these never fly on my projects. My questions are:

1. If we are going to use something shouldn't a mesh wrap be the only acceptable thing?

2. If we can eliminate all air voids by doing a thorough tape job is mesh even needed?

3. Can someone point me to the IEEE or NEC standard for aluminum foil? (I know, I know....)

Thanks all!!


Chad

Chad Snyder
Director of Operations
American Power Technology

http://www.ampowertech.com

 

[wareagle]

I do not believe you will find the answer in the NEC or IEEE. I think the procedure for terminating cable should come from the MFG. I do not think AL tin foil is an approved method for use in this process. If that termination fails and someone is injured then the fur will
fly.

 

[ssn596]

What is the Reynolds wrap going to do? I only did 12.5 Kv connections so I am not sure about 34K.

Dan Bentler

 

[tinfoil]

This is ironic, given my username, but...

Tinfoil (or any other extranaeous material) should NEVER be used in a modern termination. Between the cable mfr and the termination mfr, the required stuff should be well established (and likely provided in the termination kit)

You are probably aware that not all terminations work on every type of cable. The termination mfr is usually quite careful to stipulate what types (and diameters) of cables that they are certified for.

 

[tinfoil]

BTW, to answer the question about the purpose of the tinfoil, before the days of semi-con built into the cables, the tinfoil was thought to evenly distribute electrical stress, similar to the extra layers that are intoduced into bushings

 

[Zogzog]

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