Ronaldo Degazon wired a 220V plug by stripping insulation from wires, twisting copper strands together, bending wire ends over screws of correct pins, and tightening the cord grip and outer casing. A three-pin plug connects appliances to power supplies, with live and neutral pins creating a circuit for power to flow through and the ground pin directing voltage to a safe ground. Polarized plugs exist so cords cannot be plugged in wrongly, serving as a safeguard against electrical shock. Fuses protect appliances by melting if too large a current flows, breaking the circuit to prevent fires.

1. Ronaldo Degazon Sat. 22/09/12 Physics Lab 14 – Electricity
Aim: To wire a 220V Plug
Apparatus: 3 core wire, 3 pin 220V plug, 1 screwdriver, 1 wire stripper
Procedure:
1. The outer insulation was removed from the end of the cable.
2. The insulation from the inner stands of wire was removed.
3. The copper strands in each wire were twisted together.
4. The bare ends of the wire were bent in a clockwise direction over the screws of the
correct pins. The pins were then tightened.
5. The cord grip was tightened.
6. The outer casing was replaced.
Discussion:
A three pin plug is a device with three pins which is used to connect an electrical
appliance to a power supply when inserted into a socket.
The top two pins of the male power plug are the live and neutral pins. The live pin feeds
power into an appliance while the neutral pin draws unused power back to the power source,
creating a closed circuit for power to flow through. The ground pin acts as a safety device that is
usually connected to the metal casing of an appliance. If the appliance malfunctions and the
metal casing becomes electrified, the ground pin will direct the voltage into a safe ground so
that the appliance user is not electrocuted. Each wire connected to each pin has a certain
colour code. The earth wire is striped green and yellow, whilst the live and neutral pins are
brown and green respectively.
A plug is said to be polarized if the live and neutral pins are of different width. Polarized
plugs exist so that the electrical cord cannot be plugged in the wrong way, and serve as a
safeguard against electrical shock. The plug used in this experiment was polarized.

2. Devices that use wall electrical power normally have an electrical switch. This switch is
connected to the "hot" (live) wire coming from the electrical plug to that the device. This allows
the device to be switched off without being a shock hazard. If the switch were connected to the
"neutral" wire, the electrical device may still operate if a path to electrical ground (such as a
human touching a grounded metal surface) is present. Hence if a plug is plugged in reverse, the
neutral wire will be connected to the switch which is a hazard. Thus by only allowing the plug to
be inserted the correct way, a polarized plug is safer than an un-polarized one.
A fuse is simply a very thin wire contained in a small casing. The wire has a quite low melting
point. As current flows through the wire it heats up. If too large of a current flow is conducted,
it melts, breaking the circuit. Fuses are used to protect appliances. If too large a current flows
through an appliance it may damage it. Fuses are unlikely to act quickly enough to prevent
human electrocution – their main purpose is to prevent fires due to large currents. Fuses are
rated according to how much current they can carry before melting. In plugs fuses are usually
3A (red), 5A (black), or 13A (brown). The correct fuse for an appliance is one that is just above
the normal working current for that appliance.
It is dangerous to have an earth wire without a fuse since an earth wire is not originally part of
the circuit. The earth wire only becomes part of the circuit if there is a problem and current
reaches the casing. If an excessive current flows whilst the switch for an appliance is turned on,
the earth wire will not break the circuit and prevent damage. The fuse does this and is originally
part of the circuit.
Sources of Error:
- Wires may not have been placed into the correct corresponding pins.
- Wires may have been positioned to simply touch the pin and not fitted into the hole in
the pin.
- Wires may have been stripped too far down, thus leaving some bare wire exposed in the
plug.
- Wires may not have been screwed properly.
Precautions:
- The colour codes were carefully noted and followed to ensure that the wires were
placed into the correct pins.
- It was ensured that the wires were placed tightly in the holes that the pins provided and
that they were tightly screwed down.
- It was ensured that the wires weren’t stripped too far down.

3. - It was ensured that the wires were screwed tightly.