Electrical Grounding and Polarization

You guys and gals doing your own electrical work, pay attention to grounding and polarization for safety reasons. With some of the shoddy manufacture of (usually) small appliances, it’s common for insulation to crack or come loose so that, in the worst case, a live wire is making contact with the metal part of the device. If you happen to touch the metal, a shock is in store.

A grounding wire picks up this errant power and dumps it into a ground which can be a major pipe or a grounding connection that goes into the footer of the house. The ideal way is to connect it to the power panel., which in turn is grounded. When it’s done this way, the power that’s short-circuited is routed to the circuit breaker or fuse which does its job and cuts power to the outlet. In the ancient days, dropping an appliance like a hair dryer into a bathtub with someone in it would have disastrous consequences. With grounding, that danger is minimized if not eliminated.

So if you repair an appliance yourself, watch that all the wires are well insulated and the grounding circuit is intact and properly connected. While you are at it, be sure that the polarization is kept straight. A polarized outlet is designed so that a polarized plug can go into the socket in one way. One side is wider than the other.

Why is polarization important? An electric current comes from the live wire into the appliance and back to the source on the neutral wire. In an appliance, the on/off switch is connected to the live wire. If you have it connected the wrong way, the switch may be off but power wire is still connected. This is not a good idea. Polarization avoids the problem by forcing the plug to go in so that when the switch is off, the power is cut.

To be sure a circuit is polarized properly, you should invest in a receptacle analyzer which you plug in and it tells you if the receptacle is correctly wired. It’s not an expensive piece of equipment and if you plan to do any electrical work, it’s one of those tools you should have. In another blog piece, later on, I’ll go over the various electrical tools available and what they can do for you.