etc., are connected to the chassis. The equipotential plane is then terminated to the earth electrode subsystem
and to the main structural steel via multiple connections, to assure personnel safety and a low impedance path
for all frequencies and signals. It is again emphasized, however, that care must be taken not to create loops
which can couple signals from one system to another.
The equipotential plane also offers the following additional advantages;
Any "noisy" cable or conductor connected to the receptor, i.e., receivers, modems, etc., through or
along such a ground plane will have its field contained between the conductor and the ground plane. The noise
field can be "shorted out" by filters and bond straps because the distance between these "transmission line"
conductors is very small. Shorting out the noise field has the desirable effect of keeping noise current from
flowing over the receptor case and along any antenna input cables.
Filters at the interface terminals of equipment can operate more effectively when both terminals of
their equivalent "transmission line" are available. As in a, above, a large conducting surface makes it possible
to contain the field carried by the offending conductor, in such a way that it can be more easily prevented from
A large conducting surface may also shield or isolate rooftop antennas from noisy cables below it.
188.8.131.52 Types of Equipotential Planes. Conducting materials that can be utilized for equipotential planes are
(a) a copper grid embedded in the concrete floor such as a computer floor, (b) a subfloor of aluminum, copper,
phospher bronze screen or sheet metal laid underneath the floor tile or carpet or (c) a ceiling grid above the
equipment. Additional data and information on each of these planes can be found in para 184.108.40.206.1 of Vol II.