Is the Pi 2's power input polarity sensitive?

[utopianemo]

I'm using the Pi 2 to make an emulation machine. For various reasons(including creating a soft reset protocol and using LEDs external to the Pi's logic), I am using a beefy power supply and running the two conductors to a micro USB male jack.

At the last minute, I realized the polarity might actually matter and by reversing the positive and negative leads to the micro USB jack, I could have instantly fried my Pi 2. I don't care for fried Pi.

Anyone here able to tell me whether polarity matters at the Pi 2's input?

[W. H. Heydt]

Yes.

[drgeoff]

My understanding is:

1. No RPi models will work with reversed polarity.

2. Models A and B can be damaged by reverse polarity.

3. The + and 2 models have protection against reverse polarity.

[mahjongg]

+5V and GND should not be reversed (and cannot be when adhering to USB standards).
Doing so will immediately destroy your PI on older models, but newer models have protection (ideal diodes) to prevent this! see partial schematic of B+.

all the metal connector shells on a PI are connected to ground, so with a multimeter its easy to identify which power cable wire is connected to GND.

[ame]

Yes.

[utopianemo]

+5V and GND should not be reversed (and cannot be when adhering to USB standards).
Doing so will immediately destroy your PI on older models, but newer models have protection (ideal diodes) to prevent this! see partial schematic of B+.

all the metal connector shells on a PI are connected to ground, so with a multimeter its easy to identify which power cable wire is connected to GND.

Wow. Don't know why I didn't think of that. Thanks!