Q: Why do plugs have two different sized prongs? A: To keep them from being plugged in the wrong way - only one way will fit. While its AC and the circuit does not care, one line has been made “hot” and the other “Neutral” which should be at or very near ground potential..
Regarding this, why are there two prongs on a plug?
Definition. Many plugs have only two prongs. On two-prong plugs, there is no ground wire connection, as it's deemed unnecessary. In these plugs, one of the blades of the plugs connects to the neutral wires running through the appliance, while the other blade connects to the "hot" wires.
why do plugs have 3 prongs? "A three prong outlet has a centerpiece that connects it to the direct ground," explains Frank Thompson, an electrician with New York City Electricians. "The ground is the neutral wire that prevents a spike in the circuit or some kind of overload. It prevents your electrical unit from being burned.
Considering this, are 2 prong plugs safe?
This is what makes two-prong outlets the least safe of any type of outlet. Two-prong outlets have connections only for hot and neutral wire, hence their name. Without a third-prong for a connected ground wire, unstable electricity doesn't have a path to travel safely away from you and your electrical system.
Does it matter which way you plug outlet?
However other devices are dependent on how potential of these wires relative to ground; for these devices it does matter which way they are plugged in since the neutral wire is typically near ground potential, while the live wire's voltage oscillates around neutral.
Related Question Answers
Can I cut the ground off a plug?
The ground wire will ONLY carry current in the event of a fault from hot to chassis. This current opens the circuit breaker or fuse, disconnecting the circuit and protecting YOU from touching a hot chassis. NEVER snap the ground prong off a plug on a power tool!Can you break the third prong on a plug?
All three-prong plugs must be connected to electrical receptacles that can receive a three-pronged plug. Also, the electrical receptacle itself must have a ground circuit connected internally that goes back to the main service panel. If you cut the third prong off of a plug, you defeat the safety feature.Should the ground plug be on top or bottom?
The outlet should be oriented with the ground pin down because a person grabbing the outlet will have their index finger at the bottom side of the plug and the index finger sticks out further than the thumb. Having the ground down will keep a person's index finger from touching the live pins.Is it safe to use a 3 prong to 2 prong adapter?
2-3 prong adapters can be safe if grounded and used properly, however, they might not provide the best function. If you own a home with all 2-prong outlets it is not likely you will move the adapters around uninstalling and reinstalling them as you need to plug things in and out of your outlets.What happens if you remove the third prong?
Note: If you cut off the third prong you would would forever lose the ability to properly ground your device. It would still work, but it would be less safe. The tab that sticks out on the side can make a ground connection to the outlet (just remove the plate screw and then reinstall it through the tab).What is the difference between a receptacle and an outlet?
Outlet= A point on the wiring system at which current is taken to supply utilization equipment. Receptacle= A contact device installed at the outlet for the connection of an attachment plug. These are the devices installed so that one can plug equipment with a built in cord.How do you ground a two prong outlet?
If your house has two prong outlets with metal boxes, it is possible you can ground your outlets without overhauling the wiring. To find out whether the metal housing is grounded, purchase a circuit tester. Insert one of the tester's prongs into the hot slot (the shorter slot in the outlet).Why are some plugs not grounded?
Originally Answered: Why do some US electrical plugs have a "ground" and many do not? A device that is double insulated, meaning that both the internal wiring and the body of the device are non-conductive, are not required to have a ground wire because there is nothing the user can touch that can become energized.What happens if electrical outlet is not grounded?
If an outlet has only these two wires, but has no ground wire, it is a non-grounded, or ungrounded, outlet. A ground wire is an important safety feature. If your home's electrical system, or an individual outlet, get a surge of excess electricity, this can raise the risk of fire, shock, or electrocution.Is it safe to use a plug without the ground?
No, it is not as safe as when there is a proper ground prong and plugged into a socket with a proper ground wire leading from it to ground. In fact the house I now live in does not have a ground wire on any socket. The plugs may have a ground prong, but is not connected to anything.Why do plugs need to be grounded?
The idea behind grounding is to protect the people who use metal-encased appliances from electric shock. The casing is connected directly to the ground prong. With the case grounded, the electricity from the hot wire flows straight to ground, and this trips the breaker in the breaker box.How much does it cost to change 2 prong outlets to 3 prong?
Taking your standard 2-prong outlets into the 3-prong variety is a common project. If you have a grounded fuse box, a seasoned pro can replace the outlet in about half an hour for a total cost of $20 to $50. If your electrician must ground your fuse box or upgrade your panel, price of the project will increase.Is a three prong grounding plug with the third prong broken off is safe to use?
A three-prong grounding plug with the third prong broken-off is safe to use.Why is an appliance cord with a three prong plug safer than one with two prongs?
Why is an appliance cord with a three-prong plug safer than one with two prongs? between two wires. The standard 3 prong plug is called as grounding plug since it allows a grounding wire to be connected from the electrical circuit to the appliance.Is a 2 prong plug grounded?
These have only two wires running through them: a hot wire and a neutral wire. Two prong outlets are not grounded, which can leave you unprotected from stray currents and result in electrocution or a power surge through sensitive electronics, often destroying them in the process.What to do if a prong breaks off in an outlet?
Test it with a circuit tester to make sure the power is off. Inspect the broken prong to see how deeply it is embedded in the plug. If it is sticking out enough, grab it with a pair of needle nose pliers and pull it straight out. Put the pliers on the sides of the prong, which has a flat top and a rounded bottom.Can I change a 2 prong outlet to a 3 prong outlet?
Old-fashioned two-prong receptacles connected to two-wire cables don't have the ground wires that protect people and electrical devices in case of a fault. Yet it is possible to retrofit a new three-prong or GFCI receptacle into the same outlet box without any rewiring, as long as the box itself is grounded.Are cheater plugs safe?
Cheater plugs are not designed to be a safe solution to powering a three-pronged electrical device. If an electrical issue such as an electrical surge occurs in the electrical device the electricity can cause electrocution and electrical fires.Is the third prong on a plug necessary?
The presence of this third prong indicates that the appliance has a grounding system, and it is essential that these be plugged into grounded outlets. Some people have been known to cut off the grounding prong on an appliance plug in order to make it fit an outlet or extension cord that has no grounding slot. 
Michael Green 
