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Safe-T-Alert 35-742 wiring diagram
Flush-mount RV propane and carbon-monoxide alarm. Continuous draw is 108 mA at 12 V. Use an occupied-vehicle supply that stays powered, 14–18 AWG conductors, and a correctly fused circuit with no more than 15 A overcurrent protection. Replace after five years from installation.
- Nominal voltage
- 12 V
- Compatible systems
- 12 V
- Continuous draw
- 0.1 A
Wiring diagram
How the 35-742 is wired.
Open this example in Crimp to use your own parts and cable lengths. Review the assumptions and installation notes as you adapt the circuit.
Cable sizing for this example
Use the diagram as a starting point for your installation. Replace the example equipment and cable lengths with your own, and check the connections against your exact model's instructions.
3 m one way
12 V system
- Wire
- 1.5 mm² · 16 AWG
- Example fuse
- 1 A
- Design current
- 0.1 A
- Voltage drop
- 0.1%
Sized against ABYC E-11. The design current is the part's continuous draw. The length is one way; voltage drop includes an equal-length return.
Run-length and manufacturer assumptions
The editable example uses 3.048 m (10 ft) runs unless a shorter run is stated. Metric overviews round these to 3 m. Adapt the parts and lengths to your installation before choosing cable and protection.
Supporting parts
- 6.1 m total of 1.5 mm² (16 AWG) marine cable
- Terminations for 1.5 mm² cable, matched to the equipment's screw terminals, leads or studs
- 1 A fuse and holder on the positive run
- Heat-shrink, strain relief and terminal boots sized to the cable
Check stud sizes, fuse type, run length and how warm the space gets against the gear you actually have before you order.
Installation notes
Before you install.
Open a question for model-specific guidance and sources.
Verified against the manufacturer's documentation (rev. RV 35 Series installation and operating manual — ©2023), checked 2026-10-01. Manufacturer documentation →
Which alarm and what power does it need?
The 35-742 is the flush-mount member of Safe-T-Alert's RV 35-series propane/CO alarm family. The manual specifications, page 2, give 12 V nominal, ±15%, and 108 mA. The catalog keeps it as a continuous load, approximately 2.59 Ah/day. Use the correct variant and installation environment; this RV alarm is not an ignition-protected bilge device.
How should it be connected?
The installation instructions, page 1, identify red as the house-battery positive feed and black as return. Use 14–18 AWG wire and a properly fused circuit with no more than 15 A overcurrent protection. Fifteen amps is the allowed protection ceiling, not the alarm's current or a requirement to choose that large a fuse. The catalog's 0.108 A terminal envelope expresses normal demand rather than connector capacity.
Keep the supply energized while the vehicle is occupied. When replacing an older two-source alarm, the manual specifically warns against combining its two battery feeds: retain the intended supply and insulate the unused old wire as directed. Do not bridge house and starter batteries through the alarm wiring.
Where should it be installed?
Mount the alarm 4–20 in above the floor and follow the manual's exclusions, including staying at least 12 in from doors, windows and vents. Avoid dead-air spaces, hidden positions behind furniture and locations exposed to contamination or cleaners. A convenient cable route does not make an obstructed location suitable for gas detection.
What tests, alarms and replacement checks matter?
Test weekly and vacuum dust from the cover monthly. The operating instructions, page 2, distinguish the repeating four-beep CO pattern from the continuous-beep gas alarm. Respond to an alarm by following the evacuation and source-investigation instructions; disconnecting its power is not a way to establish safety. Use the test/silence control only as the manual permits.
Record installation date and replace the alarm five years after installation. If that date is unknown, the manual limits service to five years after manufacture. A powered green indicator does not override an expired service life or a fault indication.
Technical reference
Specifications and terminal map.
Check the model, ratings and connection points against your own unit before choosing installation hardware.
Catalog specification
Flush-mount RV propane and carbon-monoxide alarm. Continuous draw is 108 mA at 12 V. Use an occupied-vehicle supply that stays powered, 14–18 AWG conductors, and a correctly fused circuit with no more than 15 A overcurrent protection. Replace after five years from installation.
- Nominal voltage
- 12 V
- Compatible systems
- 12 V
- Continuous draw
- 0.1 A
Terminal map
Catalog connection points, current direction and planning limits. Check the manufacturer's pinout and connector ratings before installation.
+
positive · input
−
negative · input
Sources and sizing method
Equipment specifications. Model details, ratings and terminal roles come from the catalog. Check your unit’s label and current manufacturer documentation for its exact revision.
Example sizing. Sized against ABYC E-11. Boats built to UK or EU rules answer to ISO 13297 — check these figures against it before you build. Results use the example current and run length shown above. Set your actual equipment, lengths and installation conditions in Crimp before choosing hardware.
Read how the sizing worksNext step
Plan your installation with 35-742.
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