Sheilded Cat-5E Ground Loop - Myth or Reality?


I'm in the process of managing cabling for a large install (500-ish runs)
and a vendor came to me with a story about the creation of ground loops in
running sheilded+gounded cat-5e in large installations.

Does anyone have any experiences they would like to share regarding this?



Christopher K. Neitzert / 0xC10D222F /

While working at a previous employer, I had the privilege of hiring
Ralph Morrison to look at grounding in our facility. I spent some
time with Mr. Morrison talking about different methods used in
large installations. It was a great learning experience. If you
don't know Mr. Morrison, check out a few of his books on the subject.

The short answer is follow the equipment manufacturer's directions and
the local electrical code (usually the NEC in the USA). If you are
unsure, you need to ask the manufacturer and a licensed professional for
recommendations for your specific situation.

The problem is there are many theoretically correct answers. There
are lots of methods which will work under specific conditions. But
will go tragically wrong when those conditions aren't met.

BICSI, Telecommunications Cabling Installation Manual

NFPA 70, National Electrical Code

IEEE Std 1100, IEEE Recommended Practice for Powering and Grounding
Sensitive Electronic Equipment

IEEE Std 142, IEEE Recommended Practice for Grounding of Industrial and
commercial Power systems

Mil HDBK 419, Grounding, Bonding, and Shielding for Electronic Equipment
and Facilities

Federal Information Processing Standards Publication 94, Guideline on
Electrical Power for ADP Installations (A bit out of date, but explains
where some of the weirder stories come from)

The following are a bit dry, but if you want definitive information

TIA/EIA-568-A, Commercial Building Telecommunications Cabling Standard

TIA/EIA-569-A, Commercial Building Standard for Telecommunications
Pathways and Spaces

TIA/EIA-570-A, Residential and Light Commercial Telecommunication Wiring

TIA/EIA-607, Commercial Building Grounding/Bonding Requirements for

TIA/EIA-758, Customer-Owned Outside Plant Telecommunications Cabling

IS0/IEC 11801, Generic Cabling for Customer Premises