Prong Design: Like standard U.S. grounded plugs, the U.K. wall plug has three prongs. Although the built-in fuse adds bulk to the U.K. plug design, it's also safer: In case of an unexpected electrical surge, the fuse simply blows and the electricity shuts off, preventing fires, electrocutions, and other accidents.
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.
The national electrical code (NEC) calls for outlets that have a third connection for grounded plugs. If you remove the third prong the item you are using will not have the safety ground. The NEC calls for GFI outlets that use the third prong to disconnect power in the circuit when the possibility of an electric shock.
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.
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. The plugs may have a ground prong, but is not connected to anything.
If the consumer appliance is designed properly, an appliance using 2-pin (or prong) plugs may even be safer. If the consumer appliance is designed properly, an appliance using 2-pin (or prong) plugs may even be safer. 3-pin plugs have a third pin that's connected to earth or ground when plugged into the socket.
The main reason two-prong outlets are considered outdated and dangerous is due to their lack of grounding. 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.
If equipment is double insulated it does not need to grounded by cord. The equipment is grounded internally. However, some equipment has both the double insulation and a 3-prong cord for added protection. This is an extension cord for 2-prong corded equipment.
Using an extension cord with a surge protector is a fire hazard at worst, and at best runs the risk of damaging or degrading the cords of either component. Don't use a high-current surge protector with a low-current cord, and if one component uses a 14-gauge wire, the other should as well.
With continuous use over time, an extension cord can rapidly deteriorate, creating a potentially dangerous electric shock or fire hazard. Multiple plug outlets must be plugged directly into mounted electrical receptacles; they cannot be chained together.
While extension cords themselves do not draw vampire power, if an electronic device is plugged into the cord, it may draw power even when it is off. Additionally, there are fire hazards associated with the prolonged use of extension cords, so it is better to use them only temporarily.
Extension cords can overheat and cause fires when used improperly. Overheating is usually caused by overloading or connecting appliances that consume more watts than the cord can handle. Damaged extension cords can also cause fires. Extension cords should only be used temporarily.
Rule two: never plug high power capacity appliances, like space heaters, refrigerators, or microwave and toaster ovens into power strips or extension cords. These appliances have higher power capacity and need to be plugged into a wall outlet directly.
The electrician will check the color of the wires feeding to the outlet. If the white wire is connected to the smaller slot on the outlet, then the outlet was wired backwards. Simply swapping the wires at the outlet would not be an acceptable fix. The bottom line is that reversed polarity at outlets is a shock hazard.
The United States has strict codes relating to home wiring, including clearly defined colors on the outer casing of the wires. Black means hot, white signifies neutral, and green indicates ground. However, if you need to rewire a light switch or a plug socket, you may occasionally come across two black wires.
The high voltage (about 120 volts effective, 60 Hz AC) is supplied to the smaller prong of the standard polarized U.S. receptacle. It is commonly called the "hot wire". If an appliance is plugged into the receptacle, then electric current will flow through the appliance and then back to the wider prong, the neutral.
Wiring a 3 Prong Plug
The power cord has a white wire, green wire, and a black wire. The white wire is connected to the silver or light colored screw, the green wire is connected to the green screw and the black wire is connected to the gold or dark colored screw.The wide prong on the plug links the threaded base of light bulbs to the neutral terminal (the wider slot) in the receptacle. The hot side of the outlet (the side that can deliver a shock) is wired to the threaded socket if the wires are reversed.
All neutral wires of the same earthed (grounded) electrical system should have the same electrical potential, because they are all connected through the system ground. Neutral conductors are usually insulated for the same voltage as the line conductors, with interesting exceptions.
Look at the outlets in your home. The first sign of proper grounding is whether you have two-prong outlets or three. A three-prong outlet has a narrow slot, a larger slot and a "U-shaped slot." The U-shaped slot is the grounding component. Insert the circuit tester's red probe into the smaller outlet slot.
3-prong outlets without ground are legal if they are GFCI protected, with "GFCI protected" and "No equipment ground" stickers.
This is also known as a common neutral, and the circuits and neutral together are sometimes referred to as an Edison circuit. In a 3-phase system it is legal in some jurisdictions to share a single neutral wire between all three (3) phases. One neutral may not have two “hot” wires from the same phase.
