When hooking up a pair of receptacles in one electrical box, be sure your two plug-ins (electrical receptacles) are located in the same electrical box (we call this a “quad” electrical receptacle installation since each individual receptacle provides connections for two wall plugs), you’ll want to wire the hot and neutral to one pair of screws on the first receptacle, and use short black and white jumper wires to connect the proper terminals on the first receptacle to the second one in the same box.

This is a perfectly acceptable use of the second pair of screw terminals you see on the receptacles.

The ground wire can be continuous, tying the two ground screws on the receptacles together and on wards to the circuit ground.

Tips for using multiple receptacles at one location or along one wall:

• Regarding installing more than one outlet along a 12 foot wall, yes it’s perfectly permitted to exceed the minimum number of receptacles along a wall. The wiring system is unchanged except that in some cases installing two different circuits and alternating which outlet is served by which circuit may be desirable. That avoids overloading one circuit if you are plugging in several devices in one area.
• If you are going to install more than a single duplex receptacle in one location, it is recommended to use the duplex-receptacle wiring approach described in the article above. Two or more such receptacles can be ganged together in a box provided wiring, circuit amperage capacity and connections are properly selected and installed.
• A common location where we find duplexed receptacles is at kitchen counters. In those installations best practice is to power each of the pair of receptacles on different electrical circuits. This permits the user to plug in and use two appliances at one location without overloading the circuit and blowing a fuse or tripping a circuit breaker.

Yes, electrical devices such as switches and receptacles (wall plugs) need to be mounted in a code-approved plastic or metal receptacle (box) for fire safety as well as to assure that the device is mechanically secure. In fact when you purchase a “wall plug” you’ll see that its metal mounting ears and screws are spaced and designed to connect to an electrical box.

Caution:

While it’s physically possible to install a wall receptacle or “plug” without using an enclosure, doing so is dangerous, risking fire and shock, and, it’s also illegal in virtually every building code jurisdiction.

Electrical components in a building can easily cause an electrical shock, burn, or even death.  Even when a hot line switch is off, one terminal on the switch is still connected to the power source.

Before doing any work on the switch, the power source must be turned off by setting a circuit breaker to OFF or removing a fuse.

Yes, but, be careful not mix electrical receptacle types in the same box, such as 15A 240V receptacles.