Receptacles: Bootleg Grounds

Dated 2-prong ungrounded receptacle

All about bootleg grounds

The outlets in our homes are a necessary component of modern living.  Our culture is dependent on readily available access to power.  Ever since we harnessed electricity, we have witnessed the ongoing evolution for safety.  Safety, it would seem, does come without a price.  And bootleg grounds, unfortunately, are one way of avoiding that expense.

Part of the issue that comes with owning an older home is that the three-prong cords on electrical devices will not jive with older pre-1960 two-slot receptacles.  To begin with, one way to deal with this is to use an “adapter” similar to the one pictured below.   This device lets you connect your three-pronged appliances into older two-slot receptacle outlets.  So what’s the problem?  The problem is you have effectively cut out the safety mechanism the grounded electrical system provides along that third prong. 

Grounded to ungrounded plug adapter

Folks who renovate older homes for resale “flippers” know that those old two-slot relics are a turn-off for today’s homebuyers.  Their solution?  They simply upgrade all the receptacles in the home to three-slot receptacles with shiny new cover plates.  Flippers that have some sense recognize that the third slot adds necessary shock protection for the homeowner.  Yet they don’t fully understand how it works or why it’s needed.

What should they do? 

Modern 3-prong grounded receptacle

If they swap out to three-slot receptacles, the new ones need a ground wire run to each receptacle.  As a more cost-effective option, they can utilize a GFCI device for the start-of-run receptacle on that circuit.  As you can imagine, those solutions can be rather expensive. Enter the unscrupulous flipper.  The cheap-and-dirty option is to install the new receptacles with no ground connection at all. However, this is easily detected by an inexpensive three-light plug tester available at any hardware store, similar to the one shown below. These testers can easily detect when there is no ground connection present.  Many inspectors will rely solely on those three-light testers for verifying a receptacle is correctly wired. Unfortunately, there is a way to trick those testers into showing a receptacle is grounded when it actually is not. Electricians call it a “bootleg ground” or more accurately a “false ground”.

Basic three-light receptacle tester

How do you bootleg a ground? 

Please do not use this as a tutorial.  Essentially, by using a short “jumper” wire, one can connect the ground screw on the receptacle to one of the neutral screws.  This connection will deceive the basic three-light tester. How?  For starters, the tester can only recognize a crude difference in resistance.  More simply put, the tester senses the new ground slot can accept the flow of electricity.  The problem lies in that it cannot determine if the ground and neutral are isolated or traveling along the same path.

The blue wire is the bootleg jumping the ground to the neutral terminal.  This is an illegal configuration.

A seasoned inspector can sniff out bootleg grounds.  Our first clue is a recently updated older home.  Next, we check the interior of the electrical panels.  Afterward, we look for older wiring, usually determined by the sheathing or conductor materials.  If we find issues there, it’s with good reason that we keep looking.  Last but not least, finding a lack of grounding conductors in the panel along with brand-new shiny three-pronged receptacles is a dead give-away.

What do we do then? 

What’s the bottom line? 

The wiring configuration of bootleg grounds can cause serious issues.  From electrical shock, fire, or damage to equipment that utilizes a ground path while in operation. The electric shock potential exists since the ground prong in a cord is connected to the metal frame of the appliance. With a false ground, the frame becomes energized since it is being directly connected to the neutral leg.  Any grounded object that makes contact with the frame will result in current flow through that object. If that grounded object is a person, death becomes a very real possibility.

When it comes to safety in your home, the condition of your electrical system should take priority.  The problem is that most electrical problems aren’t obvious.  The other problem is most homeowners aren’t savvy enough to know what to look for.  You can certainly go out and buy all the equipment to do it yourself.  If you have the technical aptitude and are comfortable assuming that risk, by all means, you can have at it.  Although, wouldn’t it be easier and cheaper to just hire a professional that already has the skillset and the equipment?  Yeah, you know it is.  If you suspect an issue with your electrical system, or if you think you could benefit from a home inspection, schedule with us today!