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Kyanche t1_iy5fuyy wrote

Reply to comment by redditsux4me in Dashcam install to Subaru Legacy with hidden wires by Rick91981

Is the principle behind these sorts of things being safe that the wires going to the mirror have to be rated for 7.5A because the smallest fuse on that panel is 7.5A? So you can safely wire additional things inline without the risk of running too much current through the wires?

I've always been sketched out at the idea of tapping existing connections because I figured they wouldn't have much available overhead. Heheh. I mean, there's no telling if that mirror isn't already wired with lights and other things that take up the rest of the (presumed) 7.5A circuit?

It'd be much nicer if I could just make a little extension cable instead of sticking tap pins into the connector like that.

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MyMomSaysIAmCool t1_iy5imt6 wrote

You're basically right. If the fuse is 7.5a, then the wires can handle at least that.

Typically automative wiring is a bit oversized, because you can't spec an exact wire size for a circuit's draw. You have to buy the size that supports it, and that may be a bit bigger. For instance, to run 15' of wire to support your 7.5a draw, you'd use 12ga wire. But that wire can handle 10 amps, so you have plenty of reserve.

And the fuses are also a bit oversized, because nobody wants a car that'll constantly pop fuses. The device on that circuit might draw 5 amps or less normally.

Dashcams draw very little power. Google says 0.5a at 5v is typical.

The result is that you have a healthy safety margin built in, and you're not risking much by plugging a dashcam into the circuit.

Empirically, I've done it on 4 or 5 cars at this point, and have never had an issue.

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Kyanche t1_iy5l17o wrote

That's great news, because in our cadillac I so don't want to go digging through the A pillars and dashboard lol. In my Jeep it's simple and there's a gazillion videos of people doing it.

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redditsux4me t1_iy5hge9 wrote

I agree. It would be ideal to have something that just plugs in on-line with the mirror wiring using factory matching plugs, but it's not my product. It's probably a cost saving method since this works reasonably well and securely.

As far as 7.5 amp wiring, unsure on that but. Probably sized to the maximum imagined current draw for a dashcam or radar detector.

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