Un-grounded 3-prong Outlets in an older home

One of the issues which I see frequently during a home inspection are ungrounded 3-prong outlets.  We see often in older homes here in the Cincinnati area.  What likely occurs is the homeowner goes around to all of the ungrounded (originally wired) 2-prong outlets in the home, and takes the 2-prong receptacles off, and install newer 3-prong receptacles in their place.  So what are the concerns with this, and is it a small issue or a big one.  Can it be corrected easily or should you as a buyer start running away from this house?

I would begin by saying that while this is something important to address (meaning fix it), it’s also relatively easy to correct, and generally not something that would not concern me if I discovered it in a home I was going to buy.

Here is a quick primer on electricity.  It always runs in a loop, and is always looking to take the path of least resistance back to the earth or ground.  Before the 1960’s, wiring run through our homes (also referred to as circuits), had two wires,  a hot and neutral, usually wrapped in cloth sheathing.   Electricity runs in through the hot wire and comes back out the neutral wire.  If for some reason, the insulation around these wires were torn or frayed, electricity could seep out, and cause damage such as fire, or could shock or kill someone through electrocution.  Knowing that electricity is always trying to take the easiest path, (the path of least resistance) back to the earth, electricians figured out that by adding a 3rd wire to the system, a ground wire that is a relief of sorts, or an emergency exit for any electricity that leaves its original circuit of the hot and neutral wires.  The ground wire, provides the rogue electricity its easiest path to get back to the earth, and prevents electricity from racing uncontrollably through a human being, or an appliance like a computer or vacuum cleaner.  Since the mid 1960’s most of the wiring installed in homes is a 3-wire grounded cable, which contains the hot, the neutral and a bare copper ground wire.  With this new wiring, the actual receptacles changed from the 2-prongs, which had a terminal for the hot and the neutral wires only, to the 3 prongs, which has terminals for both the hot and neutral lines, and now a terminal for the ground wire.

So,  what is the answer to the question about what to do when we find ungrounded 2-prong receptacles?  For starters, any outlets in what are considered a wet area, should be grounded.  Wet areas are exactly what you think; kitchens, bathrooms, garages, the exterior of home, or an unfinished basement.   These outlets should be grounded, so in an older home, running a newer 3-wire circuit to these rooms is required.  In older homes that means replacing the old ungrounded 2-wire circuit, with a modern 3-wired grounded circuit run from the panel to its final location.   There is another solution which is acceptable, and that’s installing a GFCI or Ground Fault Circuit Interrupter type outlet.  You are probably familiar with these outlets as they have two buttons on them which read TEST and RESET.   It’s a spring loaded device that measures any imbalance of electricity (electricity that is seeping out of its circuit), and trips the circuit within a fraction of a second.   You may get a slight shock, but the flow of electricity is cut almost instantly preventing a painful, or even sometimes  fatal shock.  GFCI’s  is a topic onto itself and I’ll write about that in another article.

In the non wet areas such as the bedrooms and living rooms, most of the things that we plug in, such as lamps, clocks, or iPhone chargers don’t have an equipment ground, which is the round prod below the two prongs on a cord, and doesn’t matter if the receptacle is grounded or not.  Leaving the older style 2-prong receptacles on ungrounded circuits in these areas is acceptable.  The homeowner should be aware that this is a non-grounded outlet, and that is okay.  As I mentioned above, what a lot of people mistakenly do, is  take off the 2-prong receptacle, and install a 3-pronged receptacle in its place.  Remember, the actual grounding occurs through having the 3rd bare copper wire.  Just replacing the 2-prong with a 3-prong receptacle doesn’t change the fact that the circuit (the 2-wire system) is ungrounded.  The 3-prong receptacle is falsely giving the appearance (or illusion) of being grounded when in fact it’s not.

So what is the solution?  Basically there are two, (there may be more than 2), but the two which I point out are the obvious choices.  One is to take all the ungrounded 3-prong receptacles located in non-wet areas (bedrooms and living rooms), and replace them with 2-prong receptacles.  You can still buy 2-prong outlets at Home Depot or Lowe’s.  This is the easier and less expensive option of the two acceptable fixes.  You now know that the outlets are ungrounded, and they are identified by being a 2-prong receptacle.   The second solution is to rewire the receptacle with a newer, grounded (3-wire circuit).  This is more involved as it requires running a new wire from the electrical panel up to the room or rooms where you want to have grounded circuits.  This is more labor intensive, as you are talking about fishing wires throughout the house, which entails drilling holes in floors, and punching holes in the plaster or drywall walls and ceilings to get the wires to their desired place.   It’s hard to put a price on the cost, because a number of factors come into consideration.  The length of the wire that has to be run, the access involved, the number of holes required (both to be made and to be patched later) all vary.  Running a circuit or two through a house is not going to cost tens of thousands of dollars, but it will probably start in the high hundreds (think $400-$600) for one circuit, and go up from there depending on how many you want added.

The take away from this article.  Ungrounded 3-prong outlets in older homes (homes built prior to 1965) are quite common.    I’m more surprised when I don’t find them in an older house than when I do.   It is relatively easy to fix by installing the proper 2-prong receptacles back where they once were.  The other solution, which is costlier, is to have the wiring updated entirely, thereby having newer grounded, 3-prong circuits in your older home.


Rob Wetterstroem is an ASHI certified Home Inspector, and the owner of American Verified Home Inspections.  AVHI is a multi inspector firm located in Cincinnati, OH. 

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