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Guide to Separation of Network Cabling from EMI Sources


This standard titled “Commercial Building Standard for Telecommunications Pathways and Spaces” is a joint publication of ANSI/TIA/EIA. Its current version (ANSI/TIA/EIA/-569-B) was published in October 1, 2004 and describes EMI aspects in Article 10.3 “Horizontal pathway separation from EMI sources”.

The scope of the standard's requirements is as folows:

10.3.1 Separation between telecommunications and power cables
Co-installation of telecommunications cable and power cable is governed by applicable electrical code for safety. For minimum separation requirements of telecommunications cable from typical branch circuits (120/240V, 20A), Article 800-52 of ANSI/NFPA 70 (Ref D.3) shall be applied, for example:

  • separation from power conductors;
  • separation and barriers within raceways; and
  • separation within outlet boxes or compartments.

10.3.2 Other related requirements
The following additional requirements shall also be met:
  • the building itself shall be suitably protected from lightning (see ANSI/NFPA 780 (Ref D.4));
  • surge protection shall be applied at the electrical service entrance (see Article 280 of ANSI/NFPA 70 and section 9.11 of ANSI/IEEE (Ref. D1));
  • ANSI/TIA/EIA – 607 Commercial Building Grounding and Bonding Requirements for Telecommunications shall be followed; and
  • faulty electrical wiring shall be corrected (see section 7.5 of ANSI/IEEE 1100).

10.3.3 Reducing noise coupling
In order to further reduce noise coupling from sources such as electrical power wiring, radio frequency (RF) sources, large motors and generators, induction heaters, and arc welders, the following additional precautions should be considered:
  • Increased physical separation.
  • Electrical branch circuit line, neutral, and grounding conductors should be maintained close together (e.g., twisted, sheathed, taped, or bundled together) for minimizing inductive coupling into telecommunications cabling.
  • Use of surge protectors in branch circuits that can further limit the propagation of electrical surges. Follow guidelines in section 9.11.2 of ANSI/IEEE 1100.
  • Use of fully enclosed, grounded metallic raceway of grounded conduit or use of cable installed close to a grounded metallic surface that will also limit inductive noise coupling. Refer to clause of ANSI/TIA/EIA – 607 and section 9 of ANSI/IEEE 1100.

The original version of this standard contains a special table titled “Separation of Telecommunications Pathways from <= 480 V Power Lines”. This table was deleted from the current version of the standard, but, nevertheless, remains an important and conservative reference.

Condition Minimum Separation Distance
<2 kVa 2-5 kVa >5kVa
Unshielded power lines or electrical equipment in proximity to open or nonmetal pathways. 127 mm
( 5 in)
305 mm
(12 in)
610 mm
(24 in)
Unshielded power lines or electrical equipment in proximity to a grounded metal conduit pathway 64 mm
(2.5 in)
152 mm
(6 in)
305 mm
(12 in)
Power lines enclosed in a grounded metal conduit (or equivalent shielding) in proximity to a grounded metal conduit pathway. - 76 mm
(3 in)
152 mm
(6 in)


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