TRIGA TR-FFT, Installation & Operation Manual

PRELIMINARY: TR-FFT Fire Fighter’s Telephone Manual — LS10309-001TR-E:A  04/28/2021

11

Wiring Specifications

Prerequisites for Installation

2.5  Wiring Specifications

Induced noise (such as, the transfer of the electrical energy from one wire to another wire) can interfere with the telephone 
communication or cause false alarms. To avoid the induced noise, follow these guidelines:
•

Isolate the input wiring from the high current output and the power wiring. Do not pull one multi-conductor cable for the 

entire panel. Instead, separate the wiring as follows:

•

Do not pull the wires from the different groups through the same conduit. If you must run them together, do so for as short 

a distance as possible or use the shielded cable. Twisted, shielded wire on the audio circuits is recommended for the 

maximum protection against EMI and AFI emissions and susceptibility. Connect the shield to the Earth Ground at the 

panel. You must route the high and the low voltages separately.

•

Route the wiring around the inside perimeter of the cabinet. It should not cross the circuit board, where it could induce 

noise into the sensitive microelectronics or pick-up unwanted RF noise from the high speed circuits. See Figure 2.5 on 

page 11 for an example.

•

High frequency noise, such as that produced by the inductive reactance of a speaker or bell, can also be reduced by 

running the wire through the ferrite shield beads or by wrapping it around a ferrite toroid.

2.6  Wire Routing

You must follow the power-limited wiring techniques, which include maintaining a one-quarter inch spacing between the 
power-limited and the non-power limited circuits and separating the high and the low voltage circuits.

.

Figure 2.5  Wire Routing Example

SLC loops

Audio circuits

Relay circuit

Table 2.3  Wiring Specifications

Non-Power-limited Relay Circuit

Power-Limited

Non power-limited wiring 
must be run separately from 
power-limited wiring.