How urgent is it to resolve two-prong problems?

Question

I have read How do I use three-prong appliances when my outlets are mostly two-prong?.

I have recently moved into a house that has some two-prong and some three-prong outlets.

The place in the kitchen where the refrigerator fits has a two-prong outlet. The house had no refrigerator in it when we moved in. When the new refrigerator was delivered, the delivery person said to go to the DIY store and buy a little adapter. The first couple of days, I ran a heavy duty extension cord over to a three-prong outlet, but when I had time to go buy some adapters, I switched to that method, because I was concerned about the cord being a tripping hazard, as it had to cross the kitchen floor right where the door to the basement and garage opens.

We also have a microwave oven, a chest freezer, and a computer running on adapters. They are all on different circuits except the microwave and the fridge which share a circuit. I know this because yesterday we mapped the circuits by turning on all the lights and then flipping the circuits one at a time and observing the results.

We are planning to resolve the problem at some point. How quickly should we do that? Within one week or one month?

Answer 1

For older appliances and such, pre-electronics, it's only a safety issue and even then, only under the worst case scenarios. The National Electric Code is all about those worst case scenarios however, hence the requirement. I'm not minimizing the safety aspect, I'm just saying that people survived for a LONG time with 2 prong outlets.

That said, the OTHER issue (which was not really an issue when the change was made) is that electronics, or more specifically anything that uses a "Switch Mode Power Supply" (SMPS), needs to have a solid reference to ground so that it can deal with what's called "Common Mode Noise" created by the power supply itself. Now virtually EVERYTHING you see with any sort of electronics in is has a little SMPS, all of them creating CM noise on the line. With no reference to ground, that noise builds up, potentially degrading the life of your electronics. So the longer you wait to fix it, the shorter the life of your computers, TVs, phones, "smart" appliances etc.

But per that other thread, in a lot of cases, older houses were wired with what's called "BX" cable; flexible metal covered conductors, and that was grounded, then the outlet and switch boxes were steel as well, all connected together. So if that's what you have, AND you have a metal screw (not plastic as they are now) holding the cover plate on, you WILL get a ground connection by using those adapters and attaching them via that metal screw.

Here is a better thread illustrating this concept.

What is the purpose of the "grounding" tab/wire on a 3-prong to 2-prong adapter?