ANSI-J-STD-607-A Harger Lightning & Grounding
The purpose of this presentation is to give the user a better understanding of the requirements set forth by ANSI-J-STD-607-A, Commercial Building Grounding (Earthing) and Bonding Requirements for Telecommunications.
This standards specifies the requirements for a uniform telecommunications grounding and bonding infrastructure that shall be followed within commercial buildings where telecommunications equipment will be installed.
Telecommunications
All forms of information that are conveyed within the building, for example voice, data, video, environmental control, security, audio, etc.
Telecommunications Grounding Infrastructure
Telecommunications Grounding Infrastructure Small Building Scope
Main Elements of Telecomm Grounding and Bonding Structures
Telecomm Main Grounding Busbar (TMGB)
Telecomm Bonding Conductor (TBC)
Telecomm Bonding Backbone (TBB)
Telecomm Grounding Busbar (TGB)
Grounding Equalizer, (Formerly TBBIBC)
Telecommunications Main Grounding Busbar (TMGB)
Serves as the dedicated extension of the building grounding electrode system for the telecommunications infrastructure.
Also serves as the central attachment point for the telecommunications bonding backbone (TBB) and equipment.
Typically 1 per building.
TMGB Requirements
Have minimum dimensions of ¼” thick, 4” wide and variable in length
Be listed by a nationally recognized testing laboratory
Shall be insulated from its support by a minimum of 2”
Located so that it is accessible to telecommunications personnel
The busbar shall be cleaned prior to fastening of conductors and an anti-oxidant should be applied to the contact area to control corrosion and reduce contact resistance.
Connections to TMGB/TGB
Mechanical Connection
Surface Preparation
Antioxidant Applied
Panel Board Alternating Current Electrical Ground (ACEG)
Metallic Raceways
TBC
TBB
Panel board
Where a panelboard (electrical power panel) is located in the same room or space as the TMGB that panelboard’s alternating current equipment ground (ACEG) bus (when equipped) or the panelboard enclosure shall be bonded to the TMGB.
The TMGB shall be as close to the panelboard as practicable and shall be installed to maintain clearances required by applicable electrical codes.
The standard does not specify what size conductor to use when bonding the panel board to the TMGB. We recommend a minimum of #6 AWG and a maximum length of 13’.
Conductor Connections to the TMGB
The connections of the bonding conductor for telecommunications and the TBB to the TMGB shall utilize exothermic welding, listed compression lugs, suitable and equivalent one hole non-twisting lugs, or other irreversible compression type connections. Two-hole lugs are preferred.
The connections of the bonding telecommunications equipment to the TMGB shall utilize exothermic welding, listed compression lugs, or other irreversible compression type connections. Two-hole lugs are preferred.
2-Hole Compression Lugs
Although they’re only recommended by the standard and not required, we strongly advocate their use
2-hole lugs offer more surface area than a 1-hole lug
2-hole lugs are much less apt to loosen over time versus a 1-hole lug Compression Lugs
Trim insulation back so that bared conductor is slightly longer than barrel.
Insert conductor so that it Butts up against end of barrel. View this thru inspection port.
2 crimp minimum
Make sure end of conductor remains at end of barrel; make first crimp, repeat crimping process.
2 Crimp Minimum
Metallic Raceways/Equipment Racks
All metallic raceways for telecommunications cabling located within the same room or space as the TMGB shall be bonded to the TMGB. However, for metallic pathways containing grounding conductors where the pathway is bonded to the grounding conductor, no additional bond to the TMGB is required.
Locate an area on the rack or raceway to attach a bonding conductor. This location should have adequate access while providing minimal obstruction to rack mounted equipment.
Remove any paint, oxidation and dust from the surface using a grinding tool.
Apply a generous coating of aluminum Antioxidant Joint Compound to the mounting surface.
Attach bonding conductor using a two-hole compression lug and stainless steel hardware.
Wipe off any excess antioxidant material.
The primary protector grounding conductor shall be connected to the TMGB. This conductor is intended to conduct lightning and ac fault currents from the
telecommunication primary protectors. A minimum of 300 mm (1 ft) separation shall be maintained between this insulated conductor and any dc power cable, switchboard cable, or high frequency cables, even when placed in rigid metal conduit or EMT.
When the outside plant cable in the TEF incorporate a cable shield isolation gap, the cable shield on the building side of the gap shall be bonded to the TMGB.
In buildings where the backbone cable incorporates a shield or metallic member, this shield or metallic member shall be bonded to the TMGB or TGB.
Bonding Conductor for Telecommunications
The bonding conductor for telecommunications shall bond the TMGB to the service equipment (power) ground.
The bonding conductor for telecommunications shall be, as a minimum, the same size as the Telecommunications Bonding Backbone Conductor (TBB).
Telecomm Bonding Conductor (Bond to Electrical Service Ground)
Telecommunications Bonding Backbone (TBB)
The TBB is a conductor that interconnects all TGBs with the TMGB
Originates at the TMGB extends throughout the building using the telecommunications backbone pathways, and connects to the TGBs in all telecommunications rooms and equipment rooms.
TBB Function
The intended function of a TBB is to reduce or equalize potential differences between telecommunications systems. While the TBB will carry some current under ac
power ground fault conditions, it is not intended to provide the only ground fault return path.
TBB Material Requirements
The TBB shall be a copper conductor. The minimum TBB conductor size shall be a No. 6 AWG. The TBB should be sized at 2 kcmil per linear foot of conductor length up to a maximum of 3/0 AWG.
The TBB may be insulated; if the TBB is insulated, the insulation shall meet the fire ratings of its pathway.
The sizing of the TBB is not intended to account for the reduction or control of electromagnetic interference.
TBB Installation Requirements
The TBB conductors should be installed without splices.
Where splices are necessary, the number of splices should be a minimum and they shall be accessible and located in telecommunications spaces. Joined segments of a TBB shall be connected using exothermic welding, irreversible compression-type connectors, or equivalent.
Conductor Sizing
Applies to TBB, GE & TBC
TBB no-no’s
The interior water piping system of the building shall not be used as a TBB.
The metallic cable shield shall not be used as a TBB.
Grounding Equalizer
Conductor that connects elements of the telecommunications grounding infrastructure. (Formerly TBBIBC).
Interconnects multiple TBB’s on the top floor and every 3rd floor in between
Follows same sizing requirements as the TBB.
Telecommunications Grounding Busbar (TGB)
The TGB is the grounding connection point for telecommunications systems and equipment in the area served by that telecommunications room or equipment room.
The TGB shall have minimum dimensions of ¼” thick by 2” wide and variable in length.
Shall be listed by a nationally recognized testing laboratory.
Connections to the TGB
The TBBs and other TGBs within the same space shall be bonded to the TGB with a conductor the same size as the TBB.
Where a panelboard (electrical power panel) is located n the same room or space as the TMGB that panelboard’s alternating current equipment ground (ACEG) bus (when equipped) or the panelboard enclosure shall be bonded to the TMGB.
The TGB shall be bonded to the GE where required (Top Floor and every 3rd floor in between).
All metallic raceways for telecommunications cabling located within the same room or space as the TGB shall be bonded to the TGB
Connections of the TBB and the GE to the TGB shall utilize exothermic weld connections, listed compression two hole lug connectors, suitable and equivalent one-hole non-twisting lugs or other irreversible compression type connectors. Two-hole connectors are preferred.
Other Attachments to the TGB
Multiple TGBs may be installed within the same telecommunications room to aid in minimizing bonding conductor lengths and terminating space. In all cases, multiple TGBs within a room shall be bonded together with a conductor the same size as the TBB or with splice bars.
In buildings where the backbone telecommunications cabling incorporates a shield or metallic member, this shield or metallic member shall be bonded to the TGB where the cables are terminated or where pairs are broken out.
Short metallic pathways (e.g. wall and floor sleeves) are not required to be bonded.
Bonding to the Metal Building Frame
In a metal frame (structural steel) building, where the steel framework is readily accessible within or external to the room; each TGB and TMGB shall be bonded t the vertical steel metal frame using a minimum No. 6 AWG conductor.
When practicable because of shorter distances and, where horizontal steel members are permanently electrically bonded to vertical column members, the TGB may be bonded to these horizontal members in lieu of the vertical column members.
Summary
For over the past hour, we have presented a large amount of information concerning grounding and bonding, hopefully some of it was informative. If there are other issues you would like addressed, please contact us. Thank you for your time.