Mains Electricity Flashcards
What danger can frayed cables cause ?
The insulation has warn down exposing live wires, and therefore electricity can be conducted from them
What danger can longer cables cause ?
There is a higher resistance with longer wires, making it a higher risk of them over heating
What danger can damaged plugs cause ?
Create a risk that some of the safety features may be broken
What danger can water around appliances cause ?
Water conducts electricity, therefore the electricity/current can flow through the water, electrocuting someone or creating a fire
What danger can metal objects in plugs cause ?
Metal conducts electricity, therefore the current can flow through the metal and electrocute someone
How does insulation protect a user ?
It protects the user from electrocution by surrounding electrical conductors with insulators
What is double insulation ?
The live wire is surrounded by two casings, so the wire cannot touch the outer casing therefore no charge can be passed onto the user if touched
What are fuses ?
They are sections of wire in the circuit that melts if the current gets too high.
• when the wire melts, no current can flow through the circuit. This protects an electrical circuit from damage due to excess current
What are circuit breakers ?
They have an electromagnet that is activated when the current goes above a certain limit. The electromagnet pulls an iron switch towards it, this opens the switch and breaks the circuit.
What does an earthing wire do ?
It creates a safe route for the current to flow through if the live wire touches the casing
What is an earthing wire ?
A low-resistance path for electricity to flow
What does a resistor do ?
Slows down the movement of electrons
Is current a resistor ?
Yes
What energies are converted in a resistor ?
The Kinetic energy that was moving them, is converted into heat energy
• this is what causes heating of the wires
What is joule heating ?
Joule heating is due to electrical resistance, this can be used in heating and lighting
