| Full title | Information technology. Telecommunications bonding networks for buildings and other structures |
| Publisher | ISO and IEC, joint technical committee ISO/IEC JTC 1/SC 25 |
| Current edition | Edition 1 (2015-10) with Amendment 1 (2019-02) and Amendment 2 (2025-07). Consolidated as Edition 1.2, 2025-07 |
| Status | Current. ISO lists no newer edition under development |
| Related standards | BS EN 50310, ISO/IEC 14763-2, ANSI/TIA-607-E, IEC 60364-4-44, IEC 60364-5-54, ITU-T K.27 |
What it covers
ISO/IEC 30129 sets requirements and recommendations for the design and installation of bonds between electrically conductive elements in buildings and other structures. It applies during construction or refurbishment of buildings where telecommunications equipment is to be installed.
The aims are to:
- Minimise d.c. and a.c. potential differences in telecommunications networks caused by electromagnetic disturbance, power transients and other causes, to reduce the risk of equipment malfunction. This also reduces the risk to equipment and its cabling from electrical hazards
- Give the telecommunications installation a reliable signal reference, which improves immunity from electromagnetic interference (EMI)
It applies to the premises covered by ISO/IEC 14763-2, such as residential, office, industrial and data centre buildings. Telecommunications centres (operator buildings) are covered by ITU-T K.27 instead.
It does not apply to power supply distribution above AC 1 000 V. EMC requirements and safety requirements for power installations are outside its scope.
It is written for building architects, owners and managers, and for designers and installers of electrical and telecommunications cabling.
Structure
| Clause or annex | Subject |
|---|---|
| 4 | Conformance |
| 5 | Overview of bonding networks and equipment distribution |
| 6 | Selecting the bonding network approach: assessment, network types, performance and d.c. resistance measurement |
| 7 | Common features: protective bonding conductors, main earthing terminal (MET), entrance facility, conductors, connections, cabinets and racks, documentation |
| 8 | Dedicated telecommunications bonding network |
| 9 | Local bonding networks used with protective bonding networks (star and ring) |
| 10 | Local bonding networks used with dedicated telecommunications bonding networks |
| 11 | Mesh bonding networks, supplementary bonding grid, system reference potential plane and access floors |
| Annex A | Maintenance of bonding network performance, including galvanic corrosion (normative) |
| Annex B | Bonding conductor cross-sectional area (normative) |
| Annex C | Alternative terminology (informative) |
Key technical content
Conformance route
An assessment to Clause 6 is required first. Based on the result:
- Backbone and building entrance bonding either uses the protective bonding network, if it delivers the performance required, or meets Clause 8 for a dedicated network
- Local bonding meets Clause 9 or Clause 10, or a mesh bonding network is used to Clause 11
- Clause 7 applies to all telecommunications bonding networks
- Conductor cross-sectional areas meet Clauses 7 to 11 as amended by the region-specific application of Annex B
- Local regulations, including safety, are met
Clause 6 includes d.c. resistance requirements for protective bonding networks and for dedicated networks, and d.c. resistance measurements.
Components of a dedicated network
| Term | Abbreviation | Definition (summary) |
|---|---|---|
| Primary bonding busbar | PBB | Connected to the MET. Used to attach bonding backbone conductors and equipment bonding conductors |
| Secondary bonding busbar | SBB | Bonding point for systems and equipment in the area served by a distributor |
| Telecommunications bonding conductor | TBC | Conductor between the PBB and the MET |
| Telecommunications bonding backbone | TBB | Connects the PBB to its SBBs. Not intended as a fault current return path |
| Backbone bonding conductor | BBC | Interconnects telecommunications bonding backbones |
| Telecommunications equipment bonding conductor | TEBC | Connects a PBB or SBB to a supplementary bonding network, rack bonding conductor or item of equipment |
| Rack bonding busbar | RBB | Attachment point within a cabinet, frame or rack |
Clause 8 also covers bonds to continuous conductive pathway systems and to structural metal. Bonding conductors are specified either for d.c. resistance control or for impedance control.
Mesh bonding
The standard describes four general types of bonding network: star, ring, local mesh and mesh. Clause 11 covers the mesh isolated bonding network (MESH-IBN), with a single point of connection, and the mesh bonding network (MESH-BN).
How it relates to other standards
| Standard | Relationship |
|---|---|
| BS EN 50310 | European counterpart. EN 50310:2016 transposed ISO/IEC 30129 with minimal editorial changes and adopted its title |
| ISO/IEC 14763-2 | Planning and installation of premises cabling. Leaves bonding networks to ISO/IEC 30129. ISO/IEC 30129 applies to the premises it addresses |
| ANSI/TIA-607 | North American bonding standard. Revision C (2015) changed its terms to harmonise with ISO/IEC 30129 |
| IEC 60364 series | Electrical installation rules for protective bonding and earthing, referenced normatively |
| ITU-T K.27 | Bonding in telecommunications centres, outside the scope of ISO/IEC 30129 |
What it means in practice
- The standard does not mandate a dedicated network in every case. The Clause 6 assessment decides whether the existing protective bonding network is adequate.
- A dedicated network connects to the electrical installation at the main earthing terminal through the TBC. In the UK, electrical safety earthing and bonding are covered by BS 7671.
- Projects in Europe usually call up EN 50310 (BS EN 50310 in the UK). Projects specified to the ISO/IEC 11801 and 14763 series may call up ISO/IEC 30129. Check which one the contract names.
- Annex A (normative) covers periodic activity to maintain bonding network performance, so record the bonding network in the installation documentation.
Related reading: BS 7671 Amendment 4: PoE and ICT earthing.