GFI 8/27/21

Science with Richard Bleil

My father was, well, I guess an electrical engineer is as closely as you can describe it.  He graduated high school and immediately went to serve in the military during the Vietnamese war where he was a fighter mechanic with the Air Force.  Back then, it was not common to go to college, but rather, those with aptitude were picked up by major companies who trained them at technical jobs.  The employee expected to be with a good company for their entire career and the company was expected to take care of their employees with insurance that also covered their families, retirement and so forth. 

Dad went to work for NCR (National Cash Register) and received what would be today the equivalent of a technical training.  He went to school where they studied a series of books that were developed by NCR specifically for the training.  In the book it covered electronic components, circuitry, and even soldering.  When I was very young (maybe middle school?) he gave the books to me.  They were easy to understand, so yes, I can read an electronic schematic, solder, heck, I can even read a resistor.  I studied how each component worked and what they did, and it’s all useless today.  Today, circuits are mostly computer chips (which I’ve also studied), and nobody repairs circuit boards anymore.  If a circuit board fails, it’s just replaced. 

So, yes, I understand circuits (including digital), although I lack the experience to design them like my friend Mitch does.  But I know the difference between direct current (DC) circuits and alternating current (AC).  And yet, this week (as of the writing of this post), I’ve learned something new that I, frankly, never really thought about.

Let’s talk a bit about DC versus AC circuits.  I’ll end with AC since this is really the purpose of today’s post.  Direct current is a flow of electrons, always in one direction, from the anode of a power source (usually a battery) to the cathode.  The chemicals in the anode are undergoing oxidation, meaning they’re giving up electrons, while reduction (meaning the gaining of electrons) occurs with the chemicals at the cathode.  The anode and cathode are separated in the battery, so the only way for the electrons to get from one side to another is through a circuit where it will do work along the way.  Think about running chores.  Today I went to a home improvement store, a restaurant for lunch, a pet store, my mailbox location, a grocery store and back to home.  The carport at my home would be the battery, the work would be what I accomplished at each location, but in order for the circuit to work, it must be continuous.  If, say, a bridge was washed out on the circuit, I would not have been able to make it.  (It’s not a great analogy, since I could have cut my chores short.)  This is how a circuit works.  There must be a continuous path from the anode (negative post) to the cathode (positive post) or the electrons cannot travel since the roads for them are all one way.

In alternating current, the same thing happens, but the electrons move back and forth.  Even though there is no anode or cathode, the circuit must still be complete, both beginning and ending at the power source.  If the circuit is not complete, the electricity cannot flow.  But, even though the electrons don’t really go anywhere (just back and forth) in an alternating current, sometimes there can be an unfortunate buildup of electrons.  It’s not, but you can think of, for example, static electricity.  If you have static electricity, you know that it can discharge through your body when you touch something metal like a doorknob.  This sudden discharge can damage circuits, so alternating circuits also include a pathway to “ground”.

Ground is just that.  When that static electrical discharge goes through your body, it’s traveling to the ground under your feet.  The earth is a huge dump of electrons, so when there is an imbalance (like in the thunderstorm outside of my window right now), those excess electrons want to return to the earth, or ground.  In an alternating circuit, this is more or less a safety release.  Okay, that’s a bit simplistic, but it’ll work for this discussion.

I’m in a very old house.  There are basically two types of wall plugs, two-prong and three-prong.  The third in the three-prong plugs are the ground prongs.  This means that there is a wire or cable connected to something that goes to the earth.  In new homes, there is literally a rod driven into the earth specifically for the ground wires.  This house was built before that practice was common, and yet, I have some three-prong plugs.

As it turns out, I had two types of three prong plugs.  Some of them were functional.  There is a wire (I can show it to you when you visit if you should so desire) that goes from my upgraded circuit breaker box and attached, with good electrical connection, to a metal pipe in my plumbing.  This isn’t that ground in new houses, but it works because plumbing does eventually go through the earth to the water company.  The others is a bad habit in some older homes where somebody just replaced the two-prong plug with three without a true ground.

This (very dangerous) practice is done to avoid the two-to-three prong adapter plugs.  Those adapter plugs all have this funny little green metal loop, and while it’s not great, this is also a ground if, indeed, the adapter is installed as it is supposed to be.  The idea is to remove the screw on the outlet plate and put the screw through that loop when you screw it back into the wall.  The metal screw does make contact with the adapter, which creates a “ground” by connecting the adapter to the metal in the wall.  It’s not great, but it’s better than nothing, but replacing a two-prong plug with three without proper grounding is dangerous because when the circuit needs that ground, it just isn’t there.  This could result in damage to your electronics, or worse, a fire as had clearly happened at one of the plugs in my house prior to me moving in. 

I had an electrician visit this past week (as of the writing of this post).  I knew that some of the electric had been upgraded in this house, but not all of it.  I was hoping to discover what it would take to upgrade the rest.  Enter the GFI plugs. 

You know the GFI plugs.  Usually, you will find them in bathrooms, and maybe (like mine) kitchens.  These are all three-pronged plugs and have their own built-in circuit breaker.  These are the plugs with the buttons, a “test” and “reset”.  These plugs can be grounded, but don’t necessarily have to be.  This blew my mind. 

Here’s how they work.  If the plug senses the device needing a ground, it just trips the little built in circuit breaker.  Most circuits rarely use the ground, and usually only need it when pulling too much current.  So, if the third plug builds even the slightest charge buildup, the circuit breaker trips, and the plug turns itself off.  It’s not a true ground (although they can also be installed with a ground), but it is a safety device to prevent electrical surges.

I learned about this because my electrician didn’t want to pull a ground wire.  To be fair, that would have been very expensive indeed, but what I didn’t know is that they make GFI circuit breakers for the circuit breaker box.  He located the circuit breakers for the rooms that had two (and improperly installed three) prong plugs, and simply put those GFI breakers right in those circuit breaker locations. 

So am I safer now?  Yes, of course I am.  As it turns out, there’s more work that needs to be done (if I choose to sell this house), but for now, even though they’re not truly grounded, these plugs are now ground protected.  And, yes, this is all approved and certified and blah blah blah.  But, for now, I’m sleeping at least a little bit better. 

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