A common problem found in old houses is the presence of ungrounded outlets. Either you’re stuck with old fashioned 2-prong outlets that won’t fit your 3-prong devices or someone replaced the old outlets with 3-pronged outlets that don’t have a ground wire.
Important Disclaimer: While I am a licensed contractor, I AM NOT a licensed electrician so before you put any of this information to use check with a local electrician first. Electrical work is nothing to take lightly as you can cause fires or electrocution. Don’t do any of this work if you’re not qualified.
Since the early 1960s most electrical codes have required a ground wire to be run to all outlets and appliances, but prior to that time most wiring was just 2 wires (hot and neutral).
The ground wire provides an alternate path for electricity that may stray from an appliance or product to make it’s way safely back to the breaker or fuse box and exit the building into the main ground connection.
Electricity is like water in that it always chooses the path of least resistance. Without a grounded outlet that path is either through your appliance which will fry your TV, computer, microwave, etc. or in the worst case, through you! You may think that having a surge protect is enough, but surge protectors only work properly when attached to a grounded outlet.
There are two possible ways to fix the issue of ungrounded outlets and I’ll walk you through both of them.
How To Fix an Ungrounded Outlet
The ideal way to repair an ungrounded 3-prong outlet is to establish a continuous electrical path back to the main panel. If the outlet is installed in a metal box and that metal box has metal conduit wiring (BX cable) all the way back to the panel then you can ground your outlet with just a little work.
To make sure you have the right setup, you can use an inexpensive pig-tail electrical tester. With the circuit energized, touch one end of the tester to the hot wire (the smaller slot on the outlet) and one end of the tester to the electrical box. If the tester lights up, the box is grounded. If you get no light then there is no ground and this method won’t work for you. Skip down to Option #2 below.
If the tester lit up then all you need to do is run a bare copper wire from the ground screw on the outlet and attach it to the metal box. This will provide a ground using the equipment already in your house.
If your outlets are installed in a concrete wall there is a possibility of getting a false reading, but for wood frame structures this is a good test. If you are dealing with concrete walls call an electrician to check things out or try Option #2.
Option #2 Install a GFCI
So your house doesn’t have metal cable and you can’t get a grounded outlet that way. All is not lost. There is another option that is not quite as good as an equipment ground but will keep you safe just the same.
You can swap out your standard outlet for a GFCI outlet on any ungrounded outlets to provide protection from shocks and surges; however, you will need to add a sticker to the GFCI outlet that reads “No Equipment Ground” which comes with every GFCI outlet. This lets other folks understand what is happening behind the walls in the future.
A GFCI will “sense” the difference in the amount of electricity flowing into the circuit to that flowing out, even in amounts of current as small as 4 or 5 milliamps. The GFCI reacts quickly (less than one-tenth of a second) to trip or shut off the circuit.
So there you have it. If you have ungrounded outlets you’re not stuck having to pay thousands of dollars for a complete rewire of your house. There are options to keep your family and electronics safe.