If you spend a lot of time in commercial buildings, you may have noticed something funny about their outlets. In homes, contractors commonly install 3-prong outlets with the ground hole on the bottom and the blade holes up, but in commercial buildings, they’re the other way around. Why are outlets upside down in commercial buildings?
Outlets are upside down in commercial buildings (and most modern residences) because a plug’s blades carry electrical current. Should a metal object come in contact with the blades, a short circuit could cause sparking and fire. This won’t happen if it touches the ground plug.
If you’ve wondered why outlets are upside down in commercial buildings, wonder no more. Keep reading as we’ll explore the practical and historical reasons for topsy-turvy commercial power outlets.
Why Are Commercial Outlets Installed Upside Down?
Commercial electrical outlets have traditionally been installed upside down. Some say the upside-down outlets were a call sign used by union electricians. Others offer more practical explanations. Here are a few reasons why commercial electricians install outlets upside down.
When you plug a power cord into an outlet, you create an electrical circuit. Current flows through the cord’s copper wires and lets your printer print and your computer compute. The positive “hot” blade brings the current from the power line, and the negative “neutral” blade brings it back to the ground and completes the circuit.
So long as that circuit remains unbroken, everything runs smoothly. When you break that circuit by flipping a switch or unplugging a device, your machine loses power and turns off. But when you put a strongly conductive material between the blades, you get a short circuit. A short circuit results in a tremendous electrical power surge that can cause equipment damage, sparking, and fires.
Today most outlet covers are made of plastic. Decades earlier, they were commonly made of metal. If an outlet cover came loose and contacted a power cord’s blades, the results could be catastrophic. And even today, a worn Ethernet cable touching an electrical outlet can create a nasty and costly mess.
To limit the fire hazard, electricians install outlets in commercial buildings with the grounding plug facing up. The long third pin sends excess electricity to the ground in the event of a power surge. Should metal accidentally come into contact with the ground plug, no short circuit results.
Some outlets are always on. Their hot receptacle connects directly to the fuse box and will send power every time you plug in a device. Others are connected to a switch and will only complete a circuit when the switch is on. The National Electric Code requires switched outlets in rooms without overhead lights so you can turn your lamps on and off.
If you plug your server into a switched outlet, you may wind up losing data every time somebody turns off the light. To avoid confusion, electricians often install switched outlets in the ground-up configuration. Others mark the switched outlet with different colored outlet colors for placement consistency.
From the time we’re born, we try to identify faces. Pareidolia leads us to see faces in clouds, tree bark, and pieces of toast. And in the ground down configuration, an electrical outlet looks like a smiley face that attracts very young children’s attention.
Some contractors find it safer to install outlets upside down since the triangle is less tempting to toddlers who might greet Mr. Outlet with their fingers and metal objects. A ground-up configuration means the child is more likely to touch the harmless grounding pin than the conducting blades.
Should Outlets Be Installed Upside Down?
The question of whether outlets should be mounted ground-down or ground-up is hotly debated. Electricians argue the pros and cons of each layout. Ultimately the question comes down to a few issues.
Building and Electrical Codes
In most states, there are no specific codes regarding ground placement in residential buildings. Outlets can be placed ground-up, ground-down, or, in horizontal outlet configurations, ground-sideways. Commercial installations are more closely regulated and typically require ground-up outlets.
Before installing any outlets, check to see if your municipality or homeowner’s association has specific requirements. Many remodeling features have led to costly and nerve-wracking disputes over small details. Some inspectors will cite you for putting your outlets ground up, and others may fine you for putting them down.
Contractors must be aware of traditions because end users are, even if they don’t know it. Clients don’t understand the pros and cons of power outlet placement. But if they expect ground-down sockets and discover ground-up or vice versa, they’ll notice and complain loudly.
Many electricians install ground-down outlets in homes because that’s the traditional placement. The National Electrical Contractors Association states that any ground position is acceptable so long as the contractor remains consistent throughout the job. But they also say that ground-up or horizontal orientations are preferred, and ground-down is not recommended.
Even in areas where commercial codes are silent on outlet orientation, many commercial electricians will install ground-up outlets. And Canadians, who traditionally use ground-up outlets, wonder why we install our residential electrical outlets upside down.
Better Grip on Power Cord
Some say plugs hold better in ground-down receptacles, while others insist the opposite is true. The question depends on the plug being used. In most cases, a ground-up outlet will have slightly better gripping power than a ground-down. But in cords that angle toward the ground pin, a ground-up receptacle places additional stress on the wires.
Most wall warts sold on the American market presume a ground pin-down configuration. Getting them to stay in a pin-up outlet may prove challenging. Because most cord connections face downward pressure, they tend to become looser with time. Keeping the sturdier ground pin on the bottom may help prevent the plug from being dislodged by gravity.
Ultimately, the choice of how you place your outlets is up to you and your electrical inspector. But if you’re installing outlets in a commercial building or plugging in devices at your workplace, chances are they’ll be placed with the grounding pin up.
- Engineering Specialists Incorporated: Why Are Electrical Outlets Sometimes “Upside Down?”
- How Stuff Works: Paraedolia: Why We See Faces in Almost Everything
- National Electronic Contractors Association: Standard for Installing and Maintaining Wiring Devices
- National Electronic Contractors Association: NECA 331 Figures
- Stack Exchange: Which Way is Up (Electric Outlet?)
- UCSB ScienceLine: Why Are All the Electrical Outlets in Hospitals Upside Down?