Hardware Installation
ACX 780/781 Installation Guide 5
When lightning strikes in the area of the installation, it drastically
changes the potential of the earth. Since properly grounded Andover
Controls units respond to changes in potential more rapidly than poorly
grounded electrical systems, a poorly grounded building tries to reach
ground through the Andover Controls system. The surge of current can
destroy electronic components on the controller board.
Surges of much lower potential than lightning also impact the reliability
of Andover Controls equipment.
Inspecting the Ground
You can check your ground as follows:
1. Check your ground by first inspecting the building power distribution
panel for earth ground termination. If the ground termination is any of
the following, it is not adequate and must be corrected:
• Does not exist.
• Is connected to a corroded or galvanized pipe.
• Is connected using a small gauge wire thinner than 14 AWG (16
or 18AWG, for example, or less than 2.5 mm
2
).
2. Be sure your Andover Controls cabinet is connected to the ground
with a copper conductor that terminates at the distribution panel.
Environmental Requirements
The ACX 780/781 operates in rooms with temperatures ranging from 32
to 120°F (0° to 49°C) and with humidity between 10 and 95%,
noncondensing.
Special Wire for Card Reader Inputs
We recommend five-conductor, 22-gauge (0.35 mm
2
) shielded wire for
wiring card reader inputs.
Table 1 shows the various card brands and the maximum length for #18
gauge wire (1.0 mm
2
), then for #22 gauge wire (0.35 mm
2
).
Technical Manuals Online! - http://www.tech-man.com
To Next Page
Loading...
