Rookie mistake - forgot to mark polarity

[bunsen Member Find all posts View Profile Close bunsen]

So, I thought I'd be clever and fit an Andersen plug to a Thumper air compressor as it come with alligator clips. I made a mental note to mark the polarity on the cable as both leads are black, but I got carried away and that mental note vanished! :-(

I've done a bit of Googling, and I'm not the first one to make the mistake in doing this exact same exercise (other rookie was a Paj owner), however he took the gamble and it paid off. I'm not so gutsy.

Can anyone shed some light on what safe options I have?
- Not overly keen on opening up the compressor
- Don't want to buy another one
- Don't want it to blow up in my face, or damage the car

TIA!

[Guest Close Guest]

+ve wire usually has:
- writing on it or is striped.
- is switched.
- is fused.

The last 2 will require opening up the covers, etc.

[bunsen Member Find all posts View Profile Close bunsen]

Thanks. I did find a thread where someone had opened up the compressor and I'm guessing the +ve goes directly to the fuse.

[Hally Senior Member Find all posts View Profile Close Hally]

If you have a multimeter or know someone with one check which cable is earthed to the compressor via a continuity test.

[bunsen Member Find all posts View Profile Close bunsen]

I pulled it apart and traced the cable from the switch and fuse. Tested it out and all good.
Thanks again!