Is 12V supply wire to USB outlets rated for 15A?
Does anyone know if the wires to the USB outlets in a Coleman Light (17rx) camping trailer are rated for 15Amps? This would be a 14 (or optionally a 12) gauge wire. Acceptable answers might be:
"yes"
"no"
"it uses an xxx gauge wire" or
"don't trust it so run a new wire all the way to the battery with your own fuse."
Bonus points if there is another fuse box I haven't found yet and you can tell me where it is.
Here is the background to explain why I am obsessing over this so much.
For residential wiring the wire between the outlets and its breaker MUST be rated for the full amps of the breaker. If there is a short circuit then that wire is responsible for conducting enough current to trip the breaker. If the wire is too light for the breaker then the wire can get hot, might melt off the insulation, and could ignite a fire. This is one of the items a building inspector looks for.
My Coleman Light 17rx has a 15A fuse on the one circuit that seems to cover all the lights and USB ports and who-knows what else. This strongly suggests but does not prove to my satisfaction that the supply wire gauge to the USB ports will handle 15A.
What might an upgrade need?
-- A USB-C with PD 4.0 supplying 20V at 30W draws 3AMPs and for left and right sockets this is 6Amps.
-- A 40W device at 12V is 3.33Amps and for left and right that is 6.6Amps.
A rating of up to 10Amps might be safest. This is still under 15Amps.
If the supply wire is rated only for a couple of iphones, left and right, that's only 4 amps. The supply wires might only be rated for, say, 5Amps. That's a non-started. I sure wish I knew what they were rated for.
My friends Sprinter van conversion actually has lighter gauge supply wires all over. These are all protected by smaller fuses in separate fuse blocks located around the van. I have found no evidence for such in my Coleman Light.
so your missing the most important thing. how long is the wire? depending on the length 15amps on a 12V wire could be anywhere from a 16ga wire to a 8ga wire.
so under 4 feet you can use a 16 ga, 4 to 10 feet a 14ga, 10 to 12 a 12ga, 12 to 16 a 10ga, and 16 to 24 8ga.
most wire, except maybe cheep stuff will have the ga written on the outside of the insulation so you just need to pull enough wire to see the stamps. if its cheep you can use a set of wire strippers to get an idea what size it is.
with rv's you trend to see a lot of daisy chaining so the wire will leave the fuse box and go to every light and end up at a 12V outlet. rv's don't fall under the building code, and is the wild west. you won't fund drawings and two rv's made on the same day by different shifts could have slight variations in how the wires are run, but newer stuff is better as they have [premade harnesses they just slip in place and wire up. so really you need to turn every 12V thing on, then pull that fuse and see what all goes out. that will tell you what is on that line.
