Circuit Checks - Polarity - How?

It's easy to check polarity at an outlet. Most home supply stores sell a device that can be used to test the wiring in an outlet for less than $10.

If you check an outlet with a polarity tester and the unit shows an improper condition, have a qualified electrician inspect the electrical system. Polarity testers have a disadvantage in that they do not catch all potential problems. They can be used to confirm that something is wrong with a system, but they can seldom be used to confirm that the system is okay.