Safeguards
Describe what protective device detects an imbalance in the phase and neutral current?
RCD
When drilling a cement-based product what additional PPE is required?
P2 dust mask
What is Ohms law?
V
I R
Maximum resistance of a main earth
0.5Ω
You have isolated a circuit and locked out and tagged out. Who can remove the padlock?
Only the person who applied the tag and padlock
What type of work is changing a fuse in your own home?
Non prescribed electrical work
When starting work for the first time, what must you undergo?
Site induction
What is Pythagoras theorem?
C2 = A2 + B2
B2 = C2 - A2
Maximum resistance of an appliance earth
1Ω
How does an electric shock happen?
When the body comes into contact with two voltages at different potentials
Can a RCD be used instead of an MCB?
No
What procedure would minimise intentional energising a circuit?
Isolation and lockout
Series circuit rules
Vt = V1 +V2
I is constant
Rt = R1 + R2
Vt = Vd1 + Vd2
Minimum reading for insulation resistance
1MΩ
Describe ventricular fibrillation
The heart contract randomly, a return to a normal rhythm rarely occurs naturally
Does a portable RCD protect the user from a phase to neutral fault?
No
What is the purpose of the main earthing conductor?
To connect the main earth to the earth electrode
Parallel circuit rules
V is constant
It = I1 + I2
Rt = R1-1 + R2-1
A MIMS element resistance shall not be less than?
0.01MΩ
10,000Ω
A current test tag on an appliance tells you what?
When tested the appliance was in a safe condition
What uses an electromagnet to operate a trip mechanism in short circuit conditions?
MCB
What are the three elements of the fire triangle?
Heat, oxygen and fuel
Trigonomic equations
Soh
Cah
Toa
RCD type 2 tripping time & current
30mA
300ms/0.3s
Which of the following best describes circuit resistance?
Opposition to current flow