National Electrical Code Tips: Article 810, Radio and Television Equipment
- Article 810 seems to cover just about everything to do with radio and television equipment [810.1]. What specifically does it not cover? That would be equipment and antennas used for coupling carrier current to line conductors.
- Two new subsections were added with the 2014 NEC. 810.6 provides requirements for antenna lead-in surge protectors. These must be listed for the use and properly bonded or grounded. 810.7 provides requirements for grounding devices. These two subsections really form a set.
- The requirement for secure supporting is repeated throughout the NEC, most notably for raceway. This is really part of good workmanship [110.12]. Notably for the systems covered by Article 810, outdoor antennas and lead-in conductors must be securely supported [810.12]. This does not mean anything else in the system doesn't also fit this requirement. If you install something electrical, it must be securely supported. Period.
- Receiving stations must meet several requirements, including size of wire-strung antenna [810.16], size of lead-in [810.17], and clearances [810.18]. These are in Part II, which takes up (by page count) about half of Article 810.
- The requirements for receiving stations are mostly about the mechanics of things and there's nothing new here. For example, the bonding and grounding electrode conductors must be protected where exposed to damage [810.21(D)]. That protection rule is perhaps the most common one in the NEC. If you install anything electrical, it must be protected from damage. We know this, because the protection clause appears with all sorts of installations. It's really an Article 110 thing.
- The bonding conductor and/or grounding electrode conductor must be run in as straight a line as possible [810.21(E)]. This is the same rule we apply to lightning protection downconductors, and for the same reason (high frequency energy traveling on the skin of the conductor). This rule also appears in Article 800 and other places in the NEC.
- Oddly enough, there are requirements for the antenna systems of citizens band transmitting and receiving stations even though by law radios operating on this band are limited to 4 watts. These requirements are in Part III. It may simply be the CMP lumped in all such radios, regardless of band (e.g., 2 meter, 10 meter, 11 meter, 12 meter).
- Part IV provides the requirements for interior installation at transmitting stations. There are now only two subsections. The first is about clearances [810.70]. The second [810.71] has three requirements.
- The first requirement of 810.71 is that the transmitter is to be enclosed in a metal frame or grill and separated from the operating space by a barrier or other means [810.71(A)]. All metallic parts must be bonded. The second requirement is for bonding all external metal handles and controls accessible to personnel, ensuring they are effectively connected to the equipment grounding conductor if the transmitter is powered by the premises wiring system [810.71(B)]. If it's powered by some other means, bond and ground per 810.21.
- The third and final requirement of 810.71 that all access doors have interlocks [810.71(C)]. These must disconnect all voltages over 350V between conductors when any access door is opened.