I’m sure everyone has heard the term “ungrounded” thrown around before when talking about outdated electrical wiring, but does it really mean when an outlet has no ground? And what are the potential dangers and repair options when you find this type of wiring in your home?
As early as 1962, building officials began to enforce the new changes in the National Electrical Code requiring all new homes to have three-prong outlets installed. This was due to the increase in home appliances, many of which came equipped with three-prong cords rather than the two-prong cords you may be used to seeing on lamps and smaller appliances.
The best way to understand the importance of a ground wire within an electrical system is to remember that electricity always follows the path of least resistance. The installation of a ground wire, which corresponds to the third prong of an appliance cord, provides a fail-safe path of low resistance for electricity to travel. This is crucial in reducing both shock hazards and fire hazards. If there is a fault on that wire, like a short caused by a loose connection, that stray current will now travel down the low resistance path of the ground wire. When these faults occur on ungrounded systems the path of least resistance may instead be the person plugging in the faulty cord, resulting in an electrical shock. In addition to shock hazards, ungrounded outlets can present potential fire hazards due to the arcing of faulty electrical components that produce a tremendous amount of heat when that current cannot be safely carried away by a ground.
There are several fixes that can be used to accommodate outdated electrical systems with ungrounded outlets. First of all, never assume that an outlet is properly grounded just because it has three prongs. Until a licensed electrician has had a chance to test the outlet for a ground it can be possible for the outlet to have been installed incorrectly on the old wiring. Also never use an adapter to plug a three-prong cord into a two-prong outlet. The manufacturer put the third prong on that appliance for a reason, most likely because the appliance is capable of drawing enough current to where a fault on an ungrounded outlet could be extremely dangerous.
The best option to repair an ungrounded outlet is to have a licensed electrician rewire it entirely to include the proper ground. If this is absolutely not an option for some reason then the National Electrical Code specifies two other acceptable methods when dealing with ungrounded outlets. You can replace it with a two-prong receptacle so that only appliances that don’t require a ground can be used. However, this is not a good option for two reasons. One is that it limits you to only using appliances with two-prong cords. The other is that it does not prevent someone else from using one of those awful adapters that no one should ever use. So although two-prong outlets are still acceptable in the eyes of the code, they are not a good option.
The other slightly better option is to replace the ungrounded outlet with a Ground Fault Circuit Interrupter. These are the outlets with the TEST and RESET buttons commonly installed in kitchens, bathrooms, and unfinished/outdoor areas. Although this will not provide you with a ground, it will provide you with an added layer of protection in the event a shock occurs. The GFCI receptacle will sense an imbalance in the current path during a shock and trip the outlet before the shock can continue. Don’t forget that if you are using this method, you must identify the GFCI receptacle as ungrounded.
Overall, having a licensed electrician safely upgrade your ungrounded wiring is always the best option. Your home is a huge investment for you and there is no reason to take on such a serious risk when a qualified professional can provide you with safe, long term repair options.