20.2 Single-phase generators. This type of generator provides 115/230 Vac
single-phase power and will normally provide the FPSS conductor in the cable.
In addition, the ground terminals of the shelter and the generator should be
connected to the shelter's EESS.
20.3 Base or commercial power. When base or commercial power is used,
additional treatment of the subsystem becomes necessary, such as installation
of power-line isolation devices. (See 50.1 for filtering and isolation.) The
FPSS conductor might be provided by the power source, but it may not be below
25 ohms resistance. The ground terminal of the shelter should be connected
to the shelter EESS to provide an earth resistance of 10 ohms or less. This
ensures that a difference in potential does not exist between the FPSS and
the equipment rack, cabinet, and case ground. Power lines should be kept as
short as possible to reduce vulnerability to lightning or electromagnetic
pulse (EMP)/high-altitude electromagnetic pulse (HEMP).
30. RED equipment installation. TEMPEST approved RED equipment for
transportable communications systems provides the lowest level of risk.
However, TEMPEST approved equipment may not be available or may not meet the
operational needs. When nonTEMPEST approved equipment is used, special
treatment, such as installation of power- and signal-line filters or
isolators, is required. The need for additional protective measures should
be determined by the cognizant TEMPEST authority.