ARTICLE 810

Radio and Television Equipment

Informational Note: See Informational Note Figure 800(a) and Informational Note Figure 800(b) for an illustrative application of a bonding conductor or grounding electrode conductor.

Part I. General

Scope. This article covers antenna systems for radio and television receiving equipment, amateur and citizen band radio transmitting and receiving equipment, and certain features of transmitter safety. This article covers antennas such as wire-strung type, multi-element, vertical rod, flat, or para‐ bolic and also covers the wiring and cabling that connect them to equipment. This article does not cover equipment andantennas used for coupling carrier current to power line conductors.
Definitions. For definitions applicable to this article, see Part I of Article 100.
Other Articles. Wiring from the source of power to and between devices connected to the interior wiring system shall comply with Chapters 1 through 4 other than as modified by Parts I and II of Article 640. Wiring for audio signal processing, amplification, and reproduction equipment shall comply with Article 640. Coaxial cables that connect antennas to equipment shall comply with Article 820.
Community Television Antenna. The antenna shall comply with this article. The distribution system shall comply with Article 820.
Radio Noise Suppressors. Radio interference elimina‐ tors, interference capacitors, or noise suppressors connected to power-supply leads shall be of a listed type. They shall not be exposed to physical damage.
Antenna Lead-In Protectors. Where an antenna lead-in surge protector is installed, it shall be listed as being suitable for limiting surges on the cable that connects the antenna to the receiver/transmitter electronics and shall be connected between the conductors and the grounded shield or other ground connection. The antenna lead-in protector shall be grounded using a bonding conductor or grounding electrode conductor installed in accordance with 810.21(F).Informational Note: For requirements covering protectors for antenna lead-in conductors, refer to UL 497E, Outline of Investi‐ gation for Protectors for Antenna Lead-In Conductors.
Grounding Devices. Where bonding or grounding is required, devices used to connect a shield, a sheath, non– current-carrying metallic members of a cable, or metal parts of equipment or antennas to a bonding conductor or grounding electrode conductor shall be listed or be part of listed equip‐ ment.

Part II. Receiving Equipment — Antenna Systems

Material. Antennas and lead-in conductors shall be of hard-drawn copper, bronze, aluminum alloy, copper-clad steel, or other high-strength, corrosion-resistant material.Exception: Soft-drawn or medium-drawn copper shall be permitted for lead-in conductors where the maximum span between points of support is less than 11 m (35 ft).
Supports. Outdoor antennas and lead-in conductors shall be securely supported. The antennas or lead-in conduc‐ tors shall not be attached to the electric service mast. They shall not be attached to poles or similar structures carrying open electric light or power wires or trolley wires of over250 volts between conductors. Insulators supporting the antenna conductors shall have sufficient mechanical strength to safely support the conductors. Lead-in conductors shall be securely attached to the antennas.
Avoidance of Contacts with Conductors of Other Systems. Outdoor antennas and lead-in conductors from an antenna to a building shall not cross over open conductors of electric light or power circuits and shall be kept well away from all such circuits so as to avoid the possibility of accidentalARTICLE 810 — RADIO AND TELEVISION EQUIPMENT 810.20
contact. Where proximity to open electric light or power serv‐ ice conductors of less than 250 volts between conductors cannot be avoided, the installation shall be such as to provide a clearance of at least 600 mm (2 ft).Where practicable, antenna conductors shall be installed so as not to cross under open electric light or power conductors.
Splices. Splices and joints in antenna spans shall be made mechanically secure with approved splicing devices or by such other means as will not appreciably weaken the conduc‐ tors.
Grounding. Masts and metal structures supporting antennas shall be grounded in accordance with 810.21, unless the antenna and its related supporting mast or structure are within a zone of protection defined by a 46 m (150 ft) radius rolling sphere.
Informational Note: See 4.8.3.1 of NFPA 780-2014, Standard forthe Installation of Lightning Protection Systems, for the application of the term rolling sphere.
Size of Wire-Strung Antenna — Receiving Station.
1. Size of Antenna Conductors. Outdoor antenna conduc‐ tors for receiving stations shall be of a size not less than given in Table 810.16(A).
2. Self-Supporting Antennas. Outdoor antennas, such as vertical rods and flat, parabolic, or dipole structures, shall be of corrosion-resistant materials and of strength suitable to with‐ stand ice and wind loading conditions and shall be located well away from overhead conductors of electric light and power circuits of over 150 volts to ground, so as to avoid the possibility of the antenna or structure falling into or making accidental contact with such circuits.
Size of Lead-in — Receiving Station. Lead-in conduc‐ tors from outside antennas for receiving stations shall, for vari‐ ous maximum open span lengths, be of such size as to have a tensile strength at least as great as that of the conductors for antennas as specified in 810.16. Where the lead-in consists of two or more conductors that are twisted together, are enclosed in the same covering, or are concentric, the conductor size shall, for various maximum open span lengths, be such that the tensile strength of the combination is at least as great as that of the conductors for antennas as specified in 810.16.
Table 810.16(A) Size of Receiving Station Outdoor Antenna Conductors

Material
Less Than 11 m (35 ft)11 m to45 m (35 ftto 150 ft)
Over 45 m(150 ft)Aluminum alloy,191412hard-drawn copper

Copper-clad steel,201714bronze, or other
high-strengthmaterialMinimum Size of Conductors (AWG) Where Maximum Open Span Length Is
Clearances — Receiving Stations.

Outside of Buildings. Lead-in conductors attached to buildings shall be installed so that they cannot swing closer than 600 mm (2 ft) to the conductors of circuits of 250 volts or less between conductors, or 3.0 m (10 ft) to the conductors of circuits of over 250 volts between conductors, except that in the case of circuits not over 150 volts between conductors, where all conductors involved are supported so as to ensure perma‐ nent separation, the clearance shall be permitted to be reduced but shall not be less than 100 mm (4 in.). The clear‐ ance between lead-in conductors and any conductor forming a part of a lightning protection system shall not be less than1.8 m (6 ft). Underground conductors shall be separated at least 300 mm (12 in.) from conductors of any light or power circuits or Class 1 circuits.Exception: Where the electric light or power conductors, Class 1 conduc‐ tors, or lead-in conductors are installed in raceways or metal cable armor.Informational Note No. 1: See 250.60 for grounding associated with lightning protection components — strike termination devices. For further information, see NFPA 780-2014, Standard for the Installation of Lightning Protection Systems, which contains detailed information on grounding, bonding, and spacing from lightning protection systems, and the calculation of specific separation distances using the sideflash equation in Section 4.6.Informational Note No. 2: Metal raceways, enclosures, frames, and other non–current-carrying metal parts of electrical equip‐ ment installed on a building equipped with a lightning protec‐ tion system may require bonding or spacing from the lightning protection conductors in accordance with NFPA 780 -2014, Standard for the Installation of Lightning Protection Systems. Separa‐ tion from lightning protection conductors is typically 1.8 m (6 ft) through air or 900 mm (3 ft) through dense materials such as concrete, brick, or wood.
Antennas and Lead-ins — Indoors. Indoor antennas and indoor lead-ins shall not be run nearer than 50 mm (2 in.) to conductors of other wiring systems in the premises.Exception No. 1: Where such other conductors are in metal raceways or cable armor.Exception No. 2: Where permanently separated from such other conduc‐ tors by a continuous and firmly fixed nonconductor, such as porcelain tubes or flexible tubing.
In Boxes or Other Enclosures. Indoor antennas and indoor lead-ins shall be permitted to occupy the same box or enclosure with conductors of other wiring systems where sepa‐ rated from such other conductors by an effective permanently installed barrier.

Electrical Supply Circuits Used in Lieu of Antenna — Receiving Stations. Where an electrical supply circuit is used in lieu of an antenna, the device by which the radio receiving set is connected to the supply circuit shall be listed.
Antenna Discharge Units — Receiving Stations.
1. Where Required. Each conductor of a lead-in from an outdoor antenna shall be provided with a listed antenna discharge unit.Exception: Where the lead-in conductors are enclosed in a continuous metallic shield that either is grounded with a conductor in accordance with 810.21 or is protected by an antenna discharge unit.
2. Location. Antenna discharge units shall be located outside the building or inside the building between the point of entrance of the lead-in and the radio set or transformers and as near as practicable to the entrance of the conductors to the building. The antenna discharge unit shall not be located near combustible material or in a hazardous (classified) location as defined in Article 500.
3. Grounding. The antenna discharge unit shall be groun‐ ded in accordance with 810.21.
Bonding Conductors and Grounding Electrode Conductors — Receiving Stations. Bonding conductors and grounding electrode conductors shall comply with 810.21(A) through 810.21(K).

Material. The bonding conductor or grounding electrode conductor shall be of copper, aluminum, copper-clad steel, bronze, or similar corrosion-resistant material. Aluminum or copper-clad aluminum bonding conductors or grounding elec‐ trode conductors shall not be used where in direct contact with masonry or the earth or where subject to corrosive conditions. Where used outside, aluminum or copper-clad aluminum conductors shall not be installed within 450 mm (18 in.) of the earth.
Insulation. Insulation on bonding conductors or ground‐ ing electrode conductors shall not be required.
Supports. The bonding conductor or grounding elec‐ trode conductor shall be securely fastened in place and shall be permitted to be directly attached to the surface wired over with‐ out the use of insulating supports.Exception: Where proper support cannot be provided, the size of the bonding conductors or grounding electrode conductors shall be increased proportionately.
Physical Protection. Bonding conductors and grounding electrode conductors shall be protected where exposed to phys‐ ical damage. Where the bonding conductor or grounding elec‐ trode conductor is installed in a metal raceway, both ends of the raceway shall be bonded to the contained conductor or to the same terminal or electrode to which the bonding conduc‐ tor or grounding electrode conductor is connected.
Run in Straight Line. The bonding conductor or ground‐ ing electrode conductor for an antenna mast or antenna discharge unit shall be run in as straight a line as practicable.
Electrode. The bonding conductor or grounding elec‐ trode conductor shall be connected as required in 810.21(F)(1) through 810.21(F)(3).
1. In Buildings or Structures with an Intersystem Bonding Termination. If the building or structure served has an inter‐ system bonding termination as required by 250.94, the bonding conductor shall be connected to the intersystem bonding termination.•
2. In Buildings or Structures with Grounding Means. If thebuilding or structure served has no intersystem bonding termi‐ nation, the bonding conductor or grounding electrode conductor shall be connected to the nearest accessible location on the following:
  1. The building or structure grounding electrode system as covered in 250.50
  2. The grounded interior metal water piping systems, within1.52 m (5 ft) from its point of entrance to the building, as covered in 250.52
  3. The power service accessible means external to the build‐ ing, as covered in 250.94
  4. The nonflexible metallic power service raceway
  5. The service equipment enclosure, or
  6. The grounding electrode conductor or the grounding electrode conductor metal enclosures of the power serv‐ ice
  A bonding device intended to provide a termination point for the bonding conductor (intersystem bonding) shall not interfere with the opening of an equipment enclosure. A bond‐ ing device shall be mounted on nonremovable parts. A bond‐ ing device shall not be mounted on a door or cover even if the door or cover is nonremovable.(3) In Buildings or Structures Without an Intersystem Bonding Termination or Grounding Means. If the building or structure served has no intersystem bonding termination or grounding means as described in 810.21(F)(2), the grounding electrode conductor shall be connected to a grounding electrode as described in 250.52.
Inside or Outside Building. The bonding conductor or grounding electrode conductor shall be permitted to be run either inside or outside the building.
Size. The bonding conductor or grounding electrode conductor shall not be smaller than 10 AWG copper, 8 AWG aluminum, or 17 AWG copper-clad steel or bronze.
Common Ground. A single bonding conductor or ground‐ ing electrode conductor shall be permitted for both protective and operating purposes.
Bonding of Electrodes. A bonding jumper not smaller than 6 AWG copper or equivalent shall be connected between the radio and television equipment grounding electrode and the power grounding electrode system at the building or struc‐ ture served where separate electrodes are used.
Electrode Connection. Connections to grounding electro‐ des shall comply with 250.70.

Part III. Amateur and Citizen Band Transmitting and Receiv‐ ing Stations — Antenna Systems

Other Sections. In addition to complying with Part III, antenna systems for amateur and citizen band transmitting and receiving stations shall also comply with 810.11 through 810.15.
Size of Antenna. Antenna conductors for transmitting and receiving stations shall be of a size not less than given in Table 810.52.
Size of Lead-in Conductors. Lead-in conductors for transmitting stations shall, for various maximum span lengths, be of a size at least as great as that of conductors for antennas as specified in 810.52.
Clearance on Building. Antenna conductors for trans‐ mitting stations, attached to buildings, shall be firmly mounted at least 75 mm (3 in.) clear of the surface of the building on nonabsorbent insulating supports, such as treated pins or brackets equipped with insulators having not less than 75-mm (3-in.) creepage and airgap distances. Lead-in conductors

Table 810.52 Size of Outdoor Antenna Conductors

Minimum Size of Conductors (AWG) Where Maximum Open Span Length Is

(C) Size of Operating Bonding Conductor or Grounding Elec‐ trode Conductor. The operating bonding conductor or grounding electrode conductor for transmitting stations shall not be less than 14 AWG copper or its equivalent.

Material

Less Than 45 m (150 ft)

Over 45 m

(150 ft)

Part IV. Interior Installation — Transmitting Stations

Hard-drawn copper 14 10

Clearance from Other Conductors. All conductorsCopper-clad steel, bronze, or other high- strength material14 12inside the building shall be separated at least 100 mm (4 in.) from the conductors of any electric light, power, or signaling circuit.
attached to buildings shall also comply with these require‐ ments.Exception: Where the lead-in conductors are enclosed in a continuous metallic shield that is grounded with a conductor in accordance with 810.58, they shall not be required to comply with these requirements. Where grounded, the metallic shield shall also be permitted to be used as a conductor.
1. Entrance to Building. Except where protected with a continuous metallic shield that is grounded with a conductor in accordance with 810.58, lead-in conductors for transmitting stations shall enter buildings by one of the following methods:
  1. Through a rigid, noncombustible, nonabsorbent insulat‐ ing tube or bushing
  2. Through an opening provided for the purpose in which the entrance conductors are firmly secured so as to provide a clearance of at least 50 mm (2 in.)
  3. Through a drilled window pane
2. Protection Against Accidental Contact. Lead-in conductors to radio transmitters shall be located or installed so as to make accidental contact with them difficult.
3. Antenna Discharge Units — Transmitting Stations. Each conductor of a lead-in for outdoor antennas shall be provided with an antenna discharge unit or other suitable means that drain static charges from the antenna system.Exception No. 1: Where the lead-in is protected by a continuous metallic shield that is grounded with a conductor in accordance with 810.58, an antenna discharge unit or other suitable means shall not be required.Exception No. 2: Where the antenna is grounded with a conductor in accordance with 810.58, an antenna discharge unit or other suitable means shall not be required.
4. Bonding Conductors and Grounding Electrode Conductors — Amateur and Citizen Band Transmitting and Receiving Stations. Bonding conductors and grounding elec‐ trode conductors shall comply with 810.58(A) through 810.58(C).
1. Other Sections. All bonding conductors and grounding electrode conductors for amateur and citizen band transmit‐ ting and receiving stations shall comply with 810.21(A) through 810.21(C).
2. Size of Protective Bonding Conductor or Grounding Elec‐ trode Conductor. The protective bonding conductor or grounding electrode conductor for transmitting stations shall be as large as the lead-in but not smaller than 10 AWG copper, bronze, or copper-clad steel.
Exception No. 1: As provided in Article 640.Exception No. 2: Where separated from other conductors by raceway or some firmly fixed nonconductor, such as porcelain tubes or flexible tubing.
General. Transmitters shall comply with 810.71(A) through (C).

Enclosing. The transmitter shall be enclosed in a metal frame or grille or separated from the operating space by a barrier or other equivalent means, all metallic parts of which are effectively connected to a bonding conductor or grounding electrode conductor.
Grounding of Controls. All external metal handles and controls accessible to the operating personnel shall be effec‐ tively connected to an equipment grounding conductor if the transmitter is powered by the premises wiring system or groun‐ ded with a conductor in accordance with 810.21.
Interlocks on Doors. All access doors shall be provided with interlocks that disconnect all voltages of over 350 volts between conductors when any access door is opened.

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