In my purchased RV9 I have Aero LED Pulsar 12V LED wing tip NAV/Strobes and an Aero LED Sundial synced. The average amperage for the wings is 1.2 with a peak of 9.9. For the Sundial it's .52 with a peak of 4. The wire is 22 gauge M27500-22TG3T14, a 3 conductor cable with tin coated Cu Round shielding. AC 43.13-1B says the fuse for 22 gauge wire should be 5 amp. I keep blowing the 5amp fuse after several hours of flight. Is the combined peak amperage of the three strobes (13.9) too much for the 5A fuse and the 22 gauge wire and is that what is likely blowing the 5amp fuse? If I connect the tail strobe wire to the white light in the tail to get it off the same wire as the wing strobes will that help? What if I just disconnect the sync wire so they flash on their own and there isn't a combines peak of 13.9? Or what if I just disconnect the tail strobe? Or do I need to rewire with 18 gauge wire which takes a 10 amp fuse? Or might I have a power to ground problem with a stray wire strand?
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Strobes Blowing 5A Fuse
- Thread starter 932WT
- Start date
PilotjohnS
Well Known Member
Yup
From your description, it seems your fuse is too small. Whether or not you can just change the fuse tom a larger size or you need to rewire depends on the exact wire schematic. From your description, it is hard to tell how many wires you have going where. If you could post a wire diagram or schematic, that would be helpful.
From your description, it seems your fuse is too small. Whether or not you can just change the fuse tom a larger size or you need to rewire depends on the exact wire schematic. From your description, it is hard to tell how many wires you have going where. If you could post a wire diagram or schematic, that would be helpful.
Carl Froehlich
Well Known Member
You should have used 3 conductor 20 gauge shielded wire - and a 10 amp breaker (or fuse). 22 gauge wire is just too small for this application.
For the wire conductors:
- Strobe
- Nav
- Sync
- Shield is common ground for the Nav and Strobe.
Carl
For the wire conductors:
- Strobe
- Nav
- Sync
- Shield is common ground for the Nav and Strobe.
Carl
Last edited:
Thank you. The current wire is 22 gauge 3 wire shielded. I guess that's too small as well? It is wired as you describe. Common ground. Sync and power. The power goes to the switch then the fuse at the bus bar. Until I rewire with a bigger gauge, what if I wire the tail strobe power to the white tail position light to get it off the strobe circuit?
The only correct fix is in post #3. However: if you run the tail strobe off the tail nav light power, and flash the wingtips alternately (not together), the peak load should be a bit lower than 5 amps, which is marginally acceptable. Note that legally you now must run the nav lights all the time, to get power to the tail strobe (‘anti-collision’) light, which is required to be on all the time per the far’s. Probably should change cockpit switch labels to indicate this. You also are now unable to turn off the tail strobe ‘in the interest of safety’ without turning off the nav light - an awkward, unsafe, and illegal operation at night. Best to wire it correctly.
Carl Froehlich
Well Known Member
20 gauge is fine. Keep in mind you have three 20 gauge wires to the strobe and nav breakers - so in effect more current capability than a single 18 gauge wire.
Carl
Carl
