Correct – System Sensor SP2R1224MC and SP2W1224MC User Manual

Page 2

Figure 2. Speaker Voltage and Power Selection:

25.0V

70.7V

1/2W

1/4W

25.0V

70.7V

1/2W

1/4W

CORRECT

SW1

SW
1

INCORRECT

Table 1. Sound levels for each transformer power tap:

2 W

1 W

1/2 W 1/4 W

Reverberant

(dBA @ 10 ft.)

2 W

1 W

1/2 W 1/4 W

Anechoic

(dBA @ 10 ft.)

CAUTION

Signal levels exceeding 130% rated signal voltage can dam-
age the speaker. Consequently, an incorrect tap connection
may cause speaker damage. This means that if a 25V tap
is selected when a 70.7V amplifier is being used, speaker
damage may result. Therefore, be sure to select the proper
taps for the amplifier voltage/input power level combina-
tion being used.

Table 2. Strobe current draw measurements – 12/24
Volt applications:
NOTE: All models were only tested at the 8-17.5 and 16-33
Volt-FWR/DC limits. This does not include the 80% low-
end or 110% high-end voltage limits.

Model No.

Candela

Setting

FWR Operating

Current–Strobe

(mA RMS)

DC Operatng

Current–Strobe

(mA RMS)

12V

24V

12V

24V

SP2R1224MC

Speaker/Strobe

112

127

15/75

135

127

158

160

110

208

209

EXAMPLE: Assume you have 10 devices on a zone and
each requires 50 mA average and 2000 Ft. of 14 AWG wir-
ing (total length=outgoing+return). The voltage at the
end of the loop is 0.050 amps per device × 10 devices × 3
ohms/1,000 ft. × 2000 ft =3 volts drop.
The same number of devices using 12 AWG wire will pro-
duce only 2 volts drop. The same devices using 18 AWG
wire will produce 8 volts drop. Consult your panel manu-
facturer’s specifications, as well as SpectrAlert’s operating
voltage range to determine acceptable voltage drop.
Note: If class “A” wiring is installed, the wire length may be
up to 4 times the single wire length in this calculation.
Installation
All wiring must be installed in compliance with the Na-
tional Electrical Code (NEC) and applicable local codes as
well as special requirements of the authority having juris-
diction, using the proper wire size. This also includes all
applicable NFPA Standards, ANSI/UL 1480, UL 1971 and
NEC 760.
Electrical
1. Connect the speaker/strobe as shown in Figure 1. Keep

in mind that even though the speaker and strobe are
a single mechanical unit, they are electrically indepen-
dent and require separate power sources.

NOTE: Do NOT loop electrical wiring under terminal

screws. wires connecting the device to the control panel
must be broken at the device terminal connection in or-
der to maintain electrical supervision.

Figure 1. Electrical connections:

TO NEXT

STROBE OR EOL

INPUT FROM

POWER SUPPLY

INPUT FROM

AMPLIFIER

TO NEXT

SPEAKER OR EOL

STROBE

SPEAKER

NOTE: Supply power for strobe must be continuous for
proper operation.
2. See Figure 2 as an example of how to select a

⁄

Watt

input when a 25 volt amplifier is being used. Notice that
the header, SW1, has two shunts. One shunt is used to
select either 25 or 70.7 volts input. The other shunt is
used to select input power of

⁄

, 1 or 2 Watts. Table 1

lists the UL reverberant and anechoic output sound levels
for each power tap on the SP2 series speaker/strobes.

D900-29-00

I56-1809-009R

A0101-00

A0102-00

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