TCI Library www.telephonecollectors.info
AT&T Private Pay Phone Plus
February, 1988
For outside installations, or when an electric ground is not available, attach a ground wire to
one of the following grounds:
1. The ground post of a telephone company installed station protector if permitted by
local electrical code.
2. Power Service Ground -- This includes the grounding electrode conductor, metallic
service raceways and conduit, and the service equipment enclosure.
3. Grounded Metal Water Pipe -- The pipe must be electrically continuous, and in direct
contact with the earth for 10 feet or more.
4. Grounded Building Steel -- Ground directly to the system of a building (e.g. a ring
ground).
5. Concrete Encased Ground -- An electrode consisting of at least 20 feet (total length) of
steel reinforcing bars or rods, 1/2-inch diameter minimum, set in at least 2 inches of
concrete that is in-direct contact with moist earth.
6. Where none of the above electrodes are available, one or more of the following made
electrodes must be used:
a. Local metal underground system or structure.
b. Rod and pipe electrodes. Driven electrodes must have at least
8 feet of length in
contact with the soil.
c. Plate electrodes.
WARNING
When one of the above made electrodes is used, the ground cond:.Jcto. of b:>th !he
telephone and electrical pow er systems must be attacl:ed to ~he tsme grcund
connection.
Grounding the Electrical Service
Electrical service must be grounded according to local electrical codes. In addition, for
outdoor installations the 110-volt outlet must be bonded to the phone's ground.
:he bcncil.1g
can consist of any of the following:
• Use of a metal 110-volt outlet box mounted
i11 or ta the phone enclosure.
• For 110-volt wiring run in meta'. conduit, c:innect a grm;nd wire from the conduit to the
phone's ground. Buried or underground conduit is effectively grounded.
• Extending the green wire ground from the 110-volt outlet box to the phone's ground. This
method should only be necessary when plastic outlet boxes are used or if the 110-volt
outlet is located indoors.
Grounding the Telephone System
The telephone company will install a station protector that grounds the telephone line in
case of overvoltage (such as lightning). For outdoor installations, a station protector must be
located at or near (within 3 feet horizontally) the AT&T Private Pay Phone
Plus. If the
telephone company's station protector is not within 3 feet of the phone, an additional station
protector using gas tubes must be installed at the phone. AT&T enclosures have provisions
for mounting a station protector. The protector ground must be connected to the phone's
ground.
Connect the line terminals of the protector and the telephone line to a modular connecting
Owner Manual
Page 20
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