P4c Safe Electricals
- Specification
- Lesson Plans
- Questions
- Resources
- Extras
Recognise that a complete loop is required for a circuit to work.
State that an earthed conductor cannot become live.
Describe and recognise how resistors can be used to change the current in a circuit.
State the colour coding for live, neutral and earth wires:
- live – brown;
- neutral – blue;
- earth – green/yellow.
Describe that an earthed conductor cannot become live.
Describe reasons for the use of fuses circuit
breakers (as re-settable fuses).
Describe and recognise that “double insulated” appliances do not need earthing.
Explain the behaviour of simple circuits in terms of the flow of electric charge.
Describe how variable resistors can be used to change the current in a circuit:
- rheostat configured as a variable resistor only.
Describe the relationships between current, potential difference (pd) and resistance:
- for a given resistor, current increases as pd increases and vice versa;
- for a fixed pd, current decreases as resistance increases and vice versa.
State and use the equation:
resistance = voltage
current
Describe and explain the functions of the live, neutral and earth wires:
- live – carries the high voltage;
- neutral – the second wire to complete the circuit;
- earth – a safety wire to stop the appliance becoming live.
Describe how a wire fuse works:
- if the current becomes too large;
- wire fuse melts, breaking the circuit.
Explain why “double insulated” appliances do not need earthing:
· case of appliance is a non conductor and
State and use the equation:
resistance = voltage
current
(A change of subject may be required.)
Explain how a wire fuse reduces the risk of fire: If the appliance develops a fault:
- too large a current causes the fuse melt;
- preventing flow of current;
- prevents flex overheating and causing fire;
- prevents further damage to appliance.
Explain the reasons for the use of fuses/circuit breakers as re-settable fuses (structure and mode of operation not required).
Explain how a wire fuse and earthing protects people.
Objectives:
stuff what is important goes hereContent 3Content 4Content 5Content 2
Prior Learning:
Difficult Concepts:
Outline:
Suggested Practicals:
Extension Activities:
Homework:
Homework1
Objectives:
Content 1
Prior Learning:
Difficult Concepts:
Outline:
Suggested Practicals:
Extension Activities:
Homework:
Homework2 again