How To Upgrade Two-Prong Receptacles -The Right Way
Before 1947, the National electrical code had no grounding receptacle requirements. Even then, only laundry appliance circuits required a grounding type receptacle. In 1956, the NEC adds basements, porches and other areas where someone using the receptacle may be in contact with the ground.
In 1959 we get the additional requirement for kitchen sink receptacles to be grounded, and then in 1962 the national electric code effectively requires all receptacles to be three-prong plugs with an equipment ground.
The progression of grounding receptacle requirements follows a very similar progression to gfci receptacle requirements.
Here in Richmond we have a ton of older homes. The average age of the home we inspect is 40 years old, but we do hundreds of inspections a year on homes older than that.
Older homes have two wire systems – one hot wire (aka ungrounded wire, live wire, or black wire) and one neutral wire (aka grounded wire, or white wire)
The hot wire carries the electricity to the electrical devices, and the neutral wire carries the electricity back to main electrical panel.
Older electrical outlets were ungrounded outlets with with only two prongs – one for the hot wire, and one for the neutral wire.
What is the grounding wire for?
The ground wire bonds all metal non current carrying components together and back to the main panel. In the event of ground faults, this wire carries the flow of electricity back to main panel allowing the circuit breaker to trip.
Without a ground wire present, non current carrying metal components, such as the metal frame of an appliance, will hold current during a fault, until it becomes grounded. If a homeowner touches the frame, and is grounded, the electricity will flow through them also known as an electrical shock.
Upgrading 2-prong outlet to a 3-prong outlet
You can’t simply replace two-prong receptacles with three-prong receptacles with no consideration for how the third prong will be addressed.
There are two options that are fairly cost prohibitive.
- You could rewire the whole house. Older two wire systems can be replaced with newer three wire systems. This would obviously be very invasive and expensive.
- You could run seperate grounds to each electrical box. Running a new ground wire is cheaper than rewiring the whole house, but there are specific code requirements that make this expensive and impractical.
Aside from rewiring or running separate ground the National Electrical Code gives us some more cost effective options for replacing old two-prong outlets.
“406.4(D)(2) Non–Grounding-Type Receptacles. Where attachment to an equipment grounding conductor does not exist in the receptacle enclosure, the installation shall comply with (D)(2)(a), (D)(2)(b), or (D)(2)(c).
(a) A non–grounding-type receptacle(s) shall be permitted to be replaced with another non–grounding-type receptacle(s).
(b) A non–grounding-type receptacle(s) shall be permitted to be replaced with a ground-fault circuit interrupter-type of receptacle(s). These receptacles or their cover plates shall be marked “No Equipment Ground.” An equipment grounding conductor shall not be connected from the ground-fault circuit-interrupter-type receptacle to any outlet supplied from the ground-fault circuit-interrupter receptacle.
(c) A non–grounding-type receptacle(s) shall be permitted to be replaced with a grounding-type receptacle(s) where supplied through a ground-fault circuit interrupter. Where grounding-type receptacles are supplied through the ground-fault circuit interrupter, grounding-type receptacles or their cover plates shall be marked “GFCI Protected” and “No Equipment Ground,” visible after installation. An equipment grounding conductor shall not be connected between the grounding-type receptacles.
Informational Note No. 1: Some equipment or appliance manufacturers require that the branch circuit to the equipment or appliance includes an equipment grounding conductor.
Informational Note No. 2: See 250.114 for a list of a cord-and-plug- connected equipment or appliances that require an equipment grounding conductor.”
A is not really what anyone is looking for. It (obviously) allows you replace two prong receptacles with two prong receptacles (duh). Your new receptacle would be prettier than your old receptacle, with no added functionality.
B and C are very similar and amount to adding GFCI (ground fault circuit interrupter) protection to those circuits.
Simply put the NEC allows you upgrade old two prong receptacles to three prong receptacles, without adding a ground wire, if you add GFCI protection to those circuits AND label those circuits appropriately.
The easiest way to accomplish this is to add GFCI breakers to the breaker box. This eliminates the need to find the first receptacle in each circuit. However, if your box won’t accommodate those breakers, you will need to install GFCI outlets.
NOTE: A GFCI outlet protects all the outlets downstream of it. You do not need to replace each receptacle with a GFCI outlet – only the first one in the circuit.
How NOT To Upgrade Your Receptacles
- Don’t just replace your old receptacles with three prong receptacles without addressing the fact that you don’t have a third wire. This leaves inhabitants prone to electric shock.
- Don’t bootleg the grounds. This is a safety hazard that also leaves everyone prone to electric shock. 120 volts of electricity at 15 amps has a strong bite.
- Don’t use a cheater plug. This can damage sensitive electronics.
The Bottom Line
The grounding wire is an important safety feature of your home’s electrical system. There are code approved methods to upgrade your home with new three-prong receptacles. It is always a good idea to consulted and hire a licensed electrician when considering electrical upgrades.