I am wiring a 12v dc powered (HES) 660-12V PRE-LOAD Multi-Purpose Lock
and I can't tell which wire was positive and which was ground. When I try both wiring options it seems the lock operates the same. How do I find out whether it will fry if I wire it wrong or is it polarity sensitive?

 

Also, (reference the manual at http://www.hesinnovations.com/Other...ulti-Purpose Locks/02. HES 660 Sell Sheet.pdf ), this lock says to have a "PRE-LOAD VERSION". I have no idea what that means, but it looks like the one I bought is indeed the pre-load version. Any ideas?

 

Does the wire color description on page 3 help?
http://www.hesinnovations.com/Other...cks/06. HES 660 Installation Instructions.pdf

 

I see that it has a red and a black wire, but what I am trying to figure out is if the correct polarity is necessary since I found that it operates when I wire it correctly as well as backwards. I had to extend the wires and connected 2 of the same color wires to the lock, so at the end I cannot tell which one is which. Thats why I need the help.

 

If inverting the power supply will do any damage in the long run you would only know if you open the lock and have a look at the circuit.

Since you already inverted it and it still works it's probably ok. It depends on the component that is used to switch on/off the power elctromagnet.

 

Below is a visual of the lock opened.
Any ideas on how reverse polarity will affect this lock?

 

It's just a solenoid, the polarity doesn't matter.