It never fails. At least once a week I inspect a house that has an ungrounded electrical system. These are older homes with receptacles (or outlets, as everyone in my neck of the woods calls them) that only have two slots, and are missing the ‘3rd hole.’ That hole is for the ground conductor of the circuit. The grounding conductor wasn’t introduced until ~1962 in Louisville, KY. So if you live in an older home, that hasn’t been upgraded to modern electrical safety standards, chances are your system is ungrounded too – or at least part of it is. This could be true even if you have modern 3-hole outlets installed. I get a lot of deer-in-headlights looks when I start to talk about this stuff at my home inspections, so let me break things down for you here, and explain what all this means.
Determining if you have ungrounded outlets
Most of the time, you can simply look at your outlets and see if you still have the old ungrounded style or not. If you only see two vertical slots, they are ungrounded. However, I see lots of older houses where folks will replace their outlets with new (modern, 3-hole) outlets to make it easier to plug grounded cords in. Of course, this doesn’t make things “grounded,” you simply lose the frustration of having to use one of those cheater adapters that have the ground pin missing. If you are unsure if your receptacles are grounded, you can pick up a cheap outlet tester and it will tell you if you have a ground connected at the outlet. My receptacle tester that I use during home inspections is way more sophisticated as a circuit analyzer, but in this case essentially reports the same info: is there a ground present at the outlet. You can see an example of this in the picture below. I’m plugged into a 3-hole outlet in a 90 yr old house, but the ground icon (center light) is not lit up. This is an ungrounded 3 hole outlet.
OK, my outlets are ungrounded – Why should I care?
First, let’s briefly run through how electricity in your home works; more specifically, how the outlets work when something is plugged into them. The most important thing to remember is that electricity flows in a circuit, and it’s always trying to get back to the source. The electrons flow from the hot side of an outlet, through the device that is plugged into it (toaster/vacuum/hairdryer/etc), and back through the neutral wire to the panel (or the source.) The device you plug into the outlet completes the circuit between the hot and the neutral wires, and electricity flows through the device to run a motor, heat some coils, or whatever is needed. That is a basic 120v circuit. Pretty simple. Notice I did not bring up the use of a ground wire at all…
The hot wire is connected to the electric panel via a circuit breaker (or fuse, if your system is really old). The breaker is in place to trip (kill the power) if it senses the current flow is too high in the circuit. (This is why it’s important that your breakers be sized correctly for the wire it’s protecting.) If the breaker sees an abnormal amount of current flowing through it, it trips and shuts down the power. When a breaker trips it is known as a fault. The fault must be found and “cleared” before things can return to normal, and you can turn the power back on.
As you can see from the above example, a ground wire is not needed for a 120v circuit to function. In fact, there are lots of things you plug into your electrical system that doesn’t use the 3rd pin at all. Lamps, cell phone chargers, and toasters only have two prongs on their cords. However, there are lots of other items in your home that do utilize the ground as a safety measure. Things like refrigerators, washing machines, computers, and TVs have grounded cords. The grounded cords typically show up on items that have a metal case or have sensitive electronics inside them.
Having a fully grounded electrical system is all about safety. It’s a safety measure put in place for you, your house, and your stuff that is plugged into/connected to your house. In fact, the “ground” we are talking about is technically known as an equipment ground. There are system grounds (power company side of things), and equipment grounds (your house side of things). Everyone around here (and I would imagine many other places) just calls it a ground, so we’ll stick with that.
Grounding is in place to protect us from faults (bad things within an electrical circuit) and damage from lightning strikes. Faults just happen. Electrical motors go bad, wires break, etc. Lightning strikes also get filed under “it happens.” According to NOAA, there are 25,000,000 cloud-to-ground lightning strikes every year. Let’s break down some examples of why equipment grounding and grounded outlets are important to you and the safety of your family.
While not perfect, this video does a good job of explaining the history and progression of the electrical system in homes in the U.S.
When things go wrong
The ground wire in an electric system is in place to send rogue current safely back to the electric panel (or the source). In the event of a problem within the circuit, the ground wire provides a path for the current to safely make it back to the panel to trip the breaker or blow the fuse.
The following are some examples of what can happen when dealing with an ungrounded electrical system – especially ungrounded outlets. What you want to keep in mind is that these things occur when bad things happen. Grounding is not needed when life is good and things are rolling on as they should be. Think of it like an airbag in your car. You can drive all day every day and never need your airbag. It’s when bad things (like a wreck) happen that you sure are happy to have that safety device.
Grounding can save your bacon if things go south one day. There is a good reason the process has been required in homes since 1962. I know some of this sounds scary to folks, and while I don’t want to promote fear, I do like to promote education and respect for something that can kill you in the blink of an eye. But all is not lost. When it comes to getting this issue taken care of, there are options. In future posts, I’ll break down those for you, and explain how all that works. Check back soon…