PE safety and antenna bonding

when to bond, and when not to bond

A lot of hobby literature gets this wrong because it collapses several different things into one word: ground. RF ground is not the same thing as protective earth (PE), and static or DC continuity is not the same thing as protective bonding or lightning bonding.

EN IEC 60728-11:2023 is a safety standard (not an antenna-performance handbook). ITU-T K.71 is the in-force recommendation for customer antenna installations, and ITU-T K.56 is the in-force recommendation for radio base stations. EN IEC 60728-11:2023 was approved by CENELEC from IEC 60728-11:2023 without modification.

This article discusses bonding logic and installation cases as defined in EN/IEC and ITU texts. Always follow your national adoption and local inspection requirements, and use a qualified electrician for any work on the building earthing system.

Why the word “ground” causes so much confusion

To make matters worse, product literature often uses the same generic ground symbol for very different purposes. So the first rule is simple: do not confuse RF continuity with PE bonding.

ITU-T K.71 makes this explicit: “The following shall not be used as a bonding conductor ... the outer conductor of any coaxial cable.” That one sentence is the antidote to a huge amount of “the braid is grounded anyway” folklore.

What the EN/IEC text actually distinguishes

EN IEC 60728-11:2023 does not treat every antenna installation the same. Its structure already shows that the decision depends on context: separate clauses exist for buildings equipped with an LPS and buildings not equipped with an LPS, and it has a dedicated section called “Earthing and bonding of the antenna system.” It also includes Figure 9: “Areas of antenna-mounting in or on buildings, where earthing is not mandatory.”

That is the opposite of the simplified claim that every antenna automatically needs the same earthing response.

Antennas in the attic

For an antenna installed inside an attic, and not on a separate outdoor mast or structure, the key question is whether it sits in what K.71 calls “inherently protected sites (protected from direct strikes).” In K.71 clause 9.2.1, where an LPS does not exist and is not required, the necessary protection is against contact with mains conductors.

That does not mean “do nothing under all circumstances.” K.71 clause 8.2 says protection against contact between the antenna (or associated cabling) and a phase conductor can be achieved either by bonding the antenna system to the main earthing bar/terminal or by adequate isolation. Where adequate isolation cannot be maintained, the installation should be bonded to the building earthing system.

So the driver here is electrical safety and clearance from live conductors ... not a blanket “antenna = lightning downconductor” rule.

Antennas outside, but not on a separate metallic structure

For antennas outside the building envelope but not mounted on a separate metallic mast, tower, or support structure, there is still no blanket rule in these texts that an extra bond must be added simply because the object is an antenna.

EN IEC 60728-11 keeps separate pathways for buildings with an LPS and buildings without an LPS. K.71 adds the critical decision points: whether an LPS exists, whether an LPS is required, whether the antenna is in a protected volume, and whether there is metallic support structure that must be bonded as structure.

A separate mast or tower near the building is its own case

K.71 explicitly treats “antenna on a separate tower” as a distinct scenario and provides a decision flow (including whether the building has an LPS and what protection objective applies). The practical takeaway is not “bond everything everywhere all the time,” but “identify the installation case first.”

Antennas on metallic masts, towers, and support structures

The situation changes the moment the antenna is installed on a metallic mast, tower, feeder tray, or comparable structure.

K.56 is very clear for tower sites: feeder cables (the waveguide and the external conductor of coaxial cables) shall be bonded to the metallic tower (or feeder tray) near the antenna, and bonded again at the bonding bar near the feed-through window. It also requires the feeder tray to be bonded to the tower, and the metallic tower legs to be bonded into the earthing system.

K.71 follows the same engineering logic for customer sites: bond the mast/support structure, and bond the cable screen/shield at defined points ... using a proper bonding conductor routed directly, avoiding loops.

The antenna is a concept, not just a structure

This is where HF practice exposes the weakness of oversimplified advice. On many HF systems (EFHWs, long wires, multiband loops, terminated antennas, and similar installs), a meaningful part of the coax can become part of the radiating or counterpoise system.

In those cases, “bond the antenna” is not a useful instruction. The right question is: what exactly are you bonding, and at what point does that metal stop behaving as the antenna and start behaving as support or feeder hardware?

The standards themselves point in the right direction: K.71’s figures show bond points at the mast, the cable shield at defined locations, the MET/MEB, and the LPS. K.56 does the same at the tower, feeder tray, feeder cable, and bonding bar. That is why, in HF practice, a bond on the house side of the first non-radiating section (or on the house side of the system’s choke/bond point) can be sensible when a bond is actually required.

Why simplified dipole advice breaks down on HF

A dipole is the simplest proof that the phrase “just add a safety ground to the antenna” is often meaningless on HF. Which side do you ground? Both legs are the antenna. Ground one side and you unbalance it. Ground both sides and you no longer have an antenna.

For dipoles, doublets, and other two-arm HF antennas, the practical answer is often not a crude PE jumper to the radiator, but controlled static bleeding on both arms (symmetrical bleeder or RC paths) without randomly converting the feed system into another radiator.

The coax shield is not the bonding conductor

One of the most important sentences in K.71 is also one of the most ignored: the outer conductor of any coaxial cable shall not be used as a bonding conductor ... a specific bonding conductor shall be used.

This is the nuance many installs miss:

• You can bond from the coax outer conductor at prescribed points ... but you do it using a real bonding conductor.
• You do not treat the braid itself as the bonding conductor. DC continuity is not a substitute for a compliant bonding path.

That single distinction explains why so many ad-hoc “safety ground” installations are bad in two ways at once: they are poor RF practice and poor bonding practice. Random extra rods or random jumpers can introduce loops, noise, or unwanted current paths while still failing to provide the deliberate protective bonding strategy the standards describe (direct routing, shortest path, loop avoidance).

A practical checklist that matches the standards

• Start by classifying the install: inside protected volume (e.g., attic), outside on building, or on a separate mast/tower.
• Check the building’s LPS situation: exists / required / not present and not required.
• Identify metalwork that is structure: mast, tower, feeder tray, metallic supports ... those are bonding targets.
• Bond prescribed points, not radiators: use defined shield/mast bond points with a proper bonding conductor.
• Keep RF behavior in mind: in HF systems, place bond points where the feed system is intended to behave as feed/structure, not as radiator/counterpoise.

Conclusion

The right rule is not “always bond the antenna,” and it is not “never bond the antenna.” The right rule is to separate antenna behavior from protective bonding.

For antennas inside an attic or other protected part of the building, start by asking whether the site is inherently protected and whether the real risk is accidental contact with mains conductors. For antennas outside, start with the building’s LPS situation and whether the antenna is in a protected volume. For antennas on metallic masts, towers, trays, or other support structures, bond the structure and the prescribed feeder bond points. And in all cases, do not treat the coax shield itself as the bonding conductor.

EN IEC 60728-11 and ITU-T K.71/K.56 all point to the same conclusion: the bond belongs to the safety strategy and the support/feed system ... not automatically to the active HF radiator.

Useful code anchors

• EN IEC 60728-11:2023 ... Figure 9; clauses 11.2.2, 11.2.3, and 11.3.
• ITU-T K.71 (06/2011, in force) ... clauses 8.2, 9.2.1, 9.2.2, 9.3, and 9.4.1 (including the “outer conductor shall not be used as a bonding conductor” statement).
• ITU-T K.56 (05/2021, in force) ... clauses 7.2.1, 7.2.3, 7.3, and 8.1.1.
• Referenced by the above ... IEC 60364-5-54 (protective/bonding conductor requirements) and IEC 62305 (lightning protection system design and separation distance concepts).

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