Treebeard's Stumper 10 January 2003

Plugged In

Many holiday toys need power from batteries or plugs. Batteries are DC direct current, and you better get the plus and minus right. Household electricity is AC alternating current with no plus and minus, but the plugs are still complicated. There are 2-prong unpolarized plugs that go in either way. There are 2-prong polarized plugs that only fit one way. And there are 3-prong grounded plugs that give no choice, along with GFI "ground-fault interrupt" sockets. People lived with simple unpolarized plugs for many years. Why do we need polarized and grounded plugs and GFI sockets now? Are the "cheater" adapters dangerous?

Left to right, the photo shows a few electrical plugs and sockets I found at home:

• 3-prong 220 volt polarized socket: Note the "L"-shaped bottom hole is the key so a plug can only fit one way. High-voltage 220 volt and 3-phase are another stumper!
• 2-prong unpolarized plug: Both prongs are the same on this old extension cord. Fits anything.
• 2-prong polarized plug: Note the left prong is wider than the right prong, which is the same as the old 2-prong unpolarized plug. These fit into grounded sockets only one way, and they don't fit into old unpolarized sockets or extension cords without a cheater.
• 3-prong grounded plugs: These are becoming standard. The narrow prongs are both the same. It's interesting to think which items have these grounded plugs and which still don't.
• GFI (Ground-Fault Interrupt): Do these expensive wall sockets add another layer of protection? From what?
• "Wall wart" power pack: Most seem to have 2-prong unpolarized plugs. This is handy if you need to plug two of them into one outlet, since you can point them in different directions to fit the space.
• 2-prong unpolarized socket: New plugs won't fit these old sockets and extension cords without help. Are they dangerous?
• 3-prong grounded socket: It's getting hard to find anything else. Note the top-left slot is wider than the right, so polarized plugs can only fit one way; but the old 2-prong plugs can go either way. That's my stumper. Does it really make a difference?

A 2-prong unpolarized plug will fit either way into a polarized or grounded socket or extension cord. But a polarized or grounded plug won't fit into an unpolarized socket unless you help it with a cheater. It says something that I couldn't find an adapter at home, but I know these common fixes:

• Plug a 3-prong grounded plug into a 2-prong extension cord, and maybe shave down the socket so it fits.
• File down the wide prong on a polarized plug so it will fit into an unpolarized socket or extension cord.
• Cut the round ground pin off a 3-prong grounded plug so it will fit into an unpolarized socket or extension cord.
• Use a 3- to 2-prong adapter, with or without the extra screw-in ground wire.

Are these cheats really dangerous, even though AC power has no plus and minus polarity, and we've lived with unpolarized plugs and sockets for so many years?

I thank David Riehm for this stumper idea. As a bonus stumper, why do these all these plugs have holes drilled in the prongs?!

Answer

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