If you're not sure if it's wired right, here's a simple test: stick your finger in it. To ensure an accurate result, you'll need to compensate for geography. In the Americas: if your arm jerks around a bit and you feel funny, you did it wrong. In Europe, it's even easier. Just check if you're dead or just dead inside like usual. If you're dead, you need to swap the wires around. For India and Africa, don't bother with the test at all, there's no enforced electrical code anyways.