P/N 1036525-EN • REV F
7 / 8
Smoke detectors may not always activate and provide
warning early enough.
Smoke detectors only activate when
enough smoke reaches the detector. If a fire starts in a
chimney, wall, roof, on the other side of closed doors, or on a
different level of the property, enough smoke may not reach
the detector for it to alarm.
Smoke detectors are a significant help in reducing loss, injury,
and even death. However, no matter how good a detection
device is, nothing works perfectly under every circumstance
and we must warn you that you cannot expect a smoke
detector to ensure that you will never suffer any damage or
injury.
Current studies have shown smoke detectors may not awaken
all sleeping individuals. It is the responsibility of individuals in
the household that are capable of assisting others to provide
assistance to those who may not be awakened by the alarm
sound, or to those who may be incapable of safely evacuating
the area unassisted.
Model numbers
Figure 12: Model number codes
Features
B
6.5 to 20 VDC operation for Two-wire devices
B
6.5 to 33 VDC operation for Four-wire devices
C
8.5 to 33 VDC operation
E End-of-line
relay
H
Isolated rate-of-rise and fixed temp. sensors
R Auxiliary
relay
S
85 dBA sounder
XT Multiple criteria algorithm, rate-of-rise and fixed temp. sensors
Style
N New
style
Wiring
2 Two-wire
4 Four-wire
Product ordering
Model Description
Alarm
current (mA)
Reverse
polarity (mA)
521NB
Two-wire, photoelectric, 6.5 to 20 VDC, S09A
20
–
521NBXT
Two-wire, photoelectric, 6.5 to 20 VDC, fixed temperature and rate-of-rise heat, S09A
20
–
521NC
Two-wire, photoelectric, 8.5 to 33 VDC, S10A
20
–
521NCXT
Two-wire, photoelectric, 8.5 to 33 VDC, fixed temperature and rate-of-rise heat, S10A
20
–
521NCRXT
Two-wire, photoelectric, 8.5 to 33 VDC, fixed temperature and rate-of-rise heat, aux. relay, S11A
25
–
521NCSXT
Two-wire, photoelectric, 8.5 to 33 VDC, fixed temperature and rate-of-rise heat, temporal-three
sounder, S10A
30 13
541NB
Four-wire, photoelectric, 6.5 to 33 VDC
20
–
541NBXT
Four-wire, photoelectric, 6.5 to 33 VDC, fixed temperature and rate-of-rise heat
20
–
541NCSRXT
Four-wire, photoelectric, 8.5 to 33 VDC, fixed temperature and rate-of-rise heat, aux. relay,
temporal-three sounder
35 13
541NCSXTE
Four-wire, photoelectric, 8.5 to 33 VDC, fixed temperature and rate-of-rise heat, built-in end-of-
line relay, temporal-three sounder
45 28
541NCSRH
Four-wire, photoelectric, 8.5 to 33 VDC, isolated fixed temperature and rate-of-rise heat, aux.
relay, temporal-three sounder, nonlatching LED with automatic reset
35 13
541NCRXT
Four-wire, photoelectric, 8.5 to 33 VDC, fixed temperature and rate-of-rise heat, aux. relay
25
–
541NCXTE
Four-wire, photoelectric, 8.5 to 33 VDC, fixed temperature and rate-of-rise heat, built-in end-of-
line relay
25 –
541NCSXT
Four-wire, photoelectric, 8.5 to 33 VDC, fixed temperature and rate-of-rise heat, temporal-three
sounder
30 13
Wiring
Style
Features
