Versions Compared


  • This line was added.
  • This line was removed.
  • Formatting was changed.




2-way lighting, switch

Switch 3-way lighting, switch



Distribution board

Distribution panel, breaker panel

Earth, earthing

Ground, grounding



Residual current device (RCD)

Ground fault circuit interrupter (GFCI)

Skirting board




In general, the word energy refers to a concept that can be paraphrased as "the potential for causing changes", and therefore one can say that energy is the cause of any change. The most common definition of energy is the work that a certain force (gravitational, electromagnetic) can do.


The aim of this is guide is to provide an idea about how to transform and use the electric energy in to electric power where electric current is used to energise the equipment and devices needed in the humanitarian interventions. Understanding the basic electric concepts, knowing how to properly size the installation, how to efficiently manage it with all the safety and precautions measures in place.


Electricity is the movement of electrons. Electrons create charge, which are harnessed to produce power. Any electrical appliance - a light-bulb, a phone, a refrigerator - are all harnessing the movement of the electrons to work. The three basic principles for this guide can be explained using electrons, or more specifically, the charge they create:

  • Voltage is the Voltage - The difference in charge between two points.
  • Current (Ampere) is the - The rate at which any given charge is flowing.
  • Resistance is a Resistance - A material’s tendency to resist the flow of charge (current).


Electric Measurements

  • Power represents the - The energy consumed by the load.
  • Energythe - The amount of electricity consumed or produced during a given period of time.

Electric Potential Difference (Voltage)

Voltage (U) can be is defined as the amount of potential energy between two points on a circuit. This difference in charge between the + and – poles in a generator is measured in volts and is represented with the letter “V” in equations and schematics“V". Sometimes voltage can be called “electric pressure,” an appropriate analogy because the force provided by electric potential difference to electrons passing through a conductive material can be compared to water pressure as water moves through a pipe; the higher the volts, the greater the “water pressure”.

The available energy of the free electrons in motion is what constitutes electrical energy. Electricity production consists of forcing the electrons to move together through a conducting material by creating an electron deficit on one side of the conductor, and a surplus on the other. The terminal on the surplus side is marked (+), that on the deficit side (–).

THE VOLTAGE IS DETERMINED BY THE DISTRIBUTION NETWORK:Voltage is determined by the distribution network.  For example, 220 V between the terminals of most electrical outlets, or 1.5V between the terminals of a battery. 


An Electrical Current (I) is the flow of a free electrons between two points in a conductor. As electrons move, an amount of charge moves with them; this is called current. The number of electrons that are able to move through a given substance is governed by the physical properties of the substance itself conducting the electricity - some materials allow current to move better than others. Electrical current (I) is expressed and measured in Amperes (A) as a base unit of electrical current. Typically, when working with electrical equipment or installations, current is usually referred to in amperes. If volts (V) can be compared to the water pressure of water passing through a pipe, amperes (A) can be compared to the overall volume of water capable of flowing through the pipe at any given moment.


When a light bulb is connected to a generator, a certain quantity of electrons passes through the wires (filament) of the bulb. This electron flow corresponds to the current (I), and measured in amperes (A).

CURRENT IS A FUNCTION OF: THE POWER Current is a function of: The power (P), THE VOLTAGE The voltage (V), AND THE RESISTANCE and the resistance (R).

I = U / R


Sometimes electrons are held within their respective molecular structures while other times they are able to move around relatively freely.  The resistance of an object is the tendency of this object to oppose to the flow of electric current. In terms of electricity, the resistance of a conductive material is a measure how the device or material reduces the electric current flow through it. Every material has some degree of resistance; however it can be very low – such as copper (1Ohm per 1 meter) – or very high – such as wood (10000000 ohm per 1 meter) –. As an analogy to water flowing through a pipe, resistance is bigger when the pipe is narrower, decreasing the flow of water.