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Class A wiring requires purchase of 4100-5124 Class A Adapter Module
Only TrueAlert appliances and accessories (“devices”) are allowed on these signaling line circuit
(SLC) channels. Refer to Table 4 for a list of compatible TrueAlert devices and to the TrueAlert
device installation instructions for connection details.
Maximum of 63 devices or 75 unit loads per channel. Refer to Table 4 for unit load ratings of
TrueAlert compatible devices. The maximum number of visuals that can be synchronized on one
circuit is 43 for fixed candela and 46 for multi-candela devices. The maximum resistance between
any two visuals is 30 Ohms.
All wiring is supervised and power limited.
All wiring to be twisted pair. Wire must be minimum of 18 AWG (0.82 mm
2
) and maximum
12 AWG (3.31 mm
2
). If shielded pair is used, then the cable shield drain wire must be attached
back to the (–) Terminal at both Class A and Class B ends of this circuit. Only one wire per
terminal position.
Maximum alarm current is 3.0 A per SLC channel. Use alarm current for lowest rated appliance
nameplate voltage. Total alarm current for all 3 channels plus all current draw from AUX power
and option cards must not exceed 9 A.
Supervisory current is 0.20 mA per unit load.
Maximum length of all wire segments added together is 10,000 feet (3,048 m) per channel.
Maximum wire length from panel to any device is 2,500 feet (762 m).
T-Tapping is NOT allowed. Maximum wire distance from panel to appliance farthest from the
panel is the smaller of the values obtained from Table 5 and Table 6. Add the alarm loads of all
the devices on an SLC wire loop and apply to Table 5.
Voltage rating is 24 VDC nominal, 2 V peak-to-peak ripple, maximum.
Overvoltage suppressors are required when wiring leaves the building. Use Simplex Model
2081-9028 for wire distances of up to 1,000 feet (305 m). Use Simplex Model 2081-9044 for long
wire distances and light alarm loads. Note that the 6 Ohm line resistance of Simplex Model
2081-9044 will decrease the distances given in Table 5. Maximum two suppressors between any
device and SLC channel terminals (A or B). See the previous “General Wiring Guideline” section
for information regarding wiring that leaves a building.
Continued on next page
Wiring Class A Circuits
Class A Guidelines
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