When performing a home inspection on an older home, the inspectors at HomePro Inspections often encounter ungrounded two-prong outlet receptacles or ungrounded three-prong outlet receptacles. If it's a two-prong outlet, we will usually discuss with our client that it is ungrounded. If we find a three-prong outlet that is ungrounded (does not have a ground wire), we mark this as a defect needing correction.
Two-prong and 3-prong outlets
Code changes
The National Electrical Code (NEC) has continuously reviewed the evolution of electrical development and installation to establish safety standards since the publication of the first edition of codes in 1897. An update to the code in 1947 required that circuits supplying electricity to laundry appliances had to be grounded. In 1956, an additional code change mandated that grounding was required for basements, porches, and other exterior areas where the potential for ground contact was likely. Requirements for the grounding of kitchen sink receptacles were added in 1959, and in 1962, a code update mandated the grounding of all outlets. Since then, codes have continued to evolve, and the safety of our home’s electrical systems has improved dramatically.
Older Homes
We have many older homes here in Southeast Minnesota, and most of these homes have the older two-wire systems, where one wire is hot (ungrounded) and the other is common (grounded). The hot wire brings electricity to the electrical appliance or device, and the neutral wire returns electricity to the electrical panel.
Older homes will have two-prong outlets, which only have the hot and the neutral wire. Back in the mid- to late-60s, when appliances started providing chords with three-prongs, it was common for people to swap out their old two-pronged outlets with three-prong outlets.
This was a quick and easy fix; however, it was an unsafe fix. The problem is that even though it looks like a grounded three-prong outlet, there is no ground wire in these old homes. The house I grew up in had two-prong outlets. I remember that around 1970, when my dad was doing some remodeling, we went through and installed three-prong outlets everywhere in the house. He was tired of having to find a “cheater” every time he wanted to plug in an appliance with a three-prong cord into a two-prong outlet.
“Cheater plug”
The Ground Wire
What exactly is a ground wire? The ground wire is used to ‘bond’ all metal non-current-carrying components back to the main panel. If a ground fault occurs, this wire will direct or carry the electrical flow back to the main panel, allowing a fuse to break or a circuit breaker to trip. An ungrounded outlet has no path back to the panel and may result in an electrical shock.
How do you upgrade a two-prong outlet to a three-prong outlet?
As we have seen in many older homes, people simply replaced the old two-prong outlet with a new three-prong outlet. However, addressing the lack of a ground wire to the third prong requires further attention.
One option is to completely rewire the house, removing the older two-wire system and replacing it with a new three-wire system. Unless you're doing a complete remodel of the house, however, this is an extremely expensive and cost-prohibitive task.
The National Electrical Code provides more cost-effective options for replacing old two-prong outlets other than rewiring or running a separate ground.
2017 Code Language:
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 cord-and-plug-connected equipment or appliances that require an equipment grounding conductor.
Evaluating Your Options
Option A states that you can replace your old 2-prong outlets with new 2-prong outlets. This does not add additional protection or functionality to your electrical system, but the new outlets will look, well, new.
Options B and C are very similar, and they add GFCI (ground fault circuit interrupter) protection to those circuits.
Basically, if there is GFCI protection on those circuits, the NEC permits upgrading old two-prong outlets to three-prong outlets without adding a ground wire and by appropriately labeling those circuits as "GFCI Protected" and "No Equipment Ground."
Summary
The ground wire is the most critical safety feature of your home’s electrical system, but there are code-approved options if you want to upgrade your old two-prong outlets to three-prong outlets. We recommend that you contact a reputable licensed electrician for options on how to make these upgrades. In the end, you want your home and family to be safe.
At HomePro Inspections, our home inspectors are trained to inspect all areas of the home. Your home inspection report documents any issues found and recommends their resolution by you or a qualified professional.
Visit our website to learn more or to schedule your home inspection in the Rochester, Owatonna, and Faribault, MN areas. Contact us today at (507) 202-8942 or by email, and you can use our convenient online “Schedule Now” feature to schedule an appointment.