Electrician exam: what is tested and how to prepare

Updated 16 September 2026 · 4 min read

An electrician test checks two things: whether you understand how electricity behaves in an installation, and whether you would work safely. Expect calculations on current, power and voltage drop alongside questions on protective devices, earthing, conductor colours and the order of tests before a circuit is energised. Questions often describe a fault, such as a breaker that trips whenever a kettle is switched on, and ask for the most likely cause or the safest next step.

How this guide was made

Written for this site with AI assistance, then checked automatically before publishing. The topic table, sample questions, worked examples and study plan are generated from this site’s question bank: each worked example is recalculated by separate code, and each sample answer says where it came from.

The guide deliberately states no salaries, grades, pass marks or exam dates. Those change, and they could not be checked here, so take them from the advert itself.

This site is independent and is not affiliated with MIFOTRA or any employer.

What the questions cover

Circuit principles: Ohm's law, power, series and parallel circuits, and alternating current basics.
Supply systems: single-phase and three-phase supplies, and the roles of line, neutral and earth.
Cables: selecting a size for current and voltage drop, installation methods and insulation types.
Protection: fuses, miniature circuit breakers, residual current devices and why each is used.
Earthing and bonding: why exposed metal parts are earthed and what bonding achieves.
Safe isolation: switching off, locking off, proving dead and safe working procedures.
Inspection and testing: continuity, insulation resistance, polarity, earth fault loop impedance and RCD tests.
Fault-finding: short circuits, earth faults, open circuits and overloads, and how to tell them apart.

Where to spend your study time

The suggested emphasis reflects what this position works with day to day. It is a study guide, not a published exam blueprint.

Area	Suggested emphasis	Questions in the bank	Practise
Electrical principles and installation	71%	6,523	Electrical
Maintenance practice	29%	1,784	Electrical

Calculations you must do quickly

Most papers include arithmetic, and you should not count on a calculator, so practise by hand. The core skills are finding current from power and voltage, working out total resistance, estimating voltage drop over a cable run and calculating energy use in kilowatt-hours. Write the formula first, substitute the numbers with their units, and check that the answer is sensible: a domestic lighting circuit does not draw hundreds of amps.

Safety questions decide more than marks

Any question about working on an installation has a safety answer, and it is usually the correct one. Before work begins, the circuit is isolated, locked off, and proved dead with an approved voltage indicator that is itself checked on a known live source before and after use. Options that skip a step, such as relying on a switch position or testing with a meter on the wrong setting, are wrong even if they would usually work.

Protective devices and what trips them

Many fault questions come down to which device operates and why. A miniature circuit breaker protects against overload and short circuit, and its type, B, C or D, sets how much inrush current it tolerates before tripping. A residual current device detects current leaking to earth and trips on a small imbalance, which is why it trips when a damp appliance leaks current even though the circuit is not overloaded. Knowing the difference turns many fault scenarios into easy marks.

Testing in the right order

Tests before energising follow a logical order, because some are only safe on a dead circuit. Continuity of protective conductors and insulation resistance come first, with the supply off, and polarity is confirmed before connection. Earth fault loop impedance and RCD operation need the supply, so they come after. Questions asking which test comes first, or which test finds a particular fault, reward candidates who understand why the order exists.

How to prepare

Split your study between calculations, standards and practical knowledge. Do a few calculations every day until the formulas are automatic. Draw circuits from memory: a lighting circuit with two-way switching, a radial socket circuit, and a distribution board with RCD protection. If you can use a workshop, practise safe isolation and testing under supervision, because questions written by practising electricians assume you have done these tasks yourself.

Try a few now

A technician measures voltage at a standard 120V receptacle and gets 120V between hot and neutral, but 0V between neutral and ground, and 60V between hot and ground. What is the most likely fault?
1. The equipment grounding conductor is open or floating
2. The receptacle is wired correctly
3. There is a direct short between hot and neutral
4. The hot and neutral wires are reversed
Show the answer
A. The equipment grounding conductor is open or floating
If the ground is floating (open), capacitive coupling can cause the hot-to-ground voltage to read arbitrarily (often around half voltage, like 60V) with a high-impedance digital multimeter.
Original practice question, written against published exam objectives. Open this question
During an inspection of a commercial kitchen, you notice the 125V, 15A receptacles near the sinks lack GFCI protection. The manager claims they are exempt because they are dedicated for refrigerators. How should you respond?
1. GFCI is only required for 250V receptacles in kitchens
2. All 15A and 20A, 125V receptacles in a commercial kitchen require GFCI protection, regardless of their intended use
3. The manager is correct; dedicated appliance receptacles are exempt
4. Only receptacles within 6 feet of the sink need GFCI
Show the answer
B. All 15A and 20A, 125V receptacles in a commercial kitchen require GFCI protection, regardless of their intended use
NEC 210.8(B) mandates that all 15A and 20A, 125V receptacles in commercial kitchens must be GFCI protected. There are no exemptions for dedicated equipment.
Original practice question, written against published exam objectives. Open this question
A technician is running a new 50A branch circuit to a range. They pull 8 AWG THHN copper wire through an attic where the ambient temperature reaches 120°F. During inspection, the installation fails. Why?
1. The wire gauge is too small after applying ambient temperature derating factors
2. The breaker must be upgraded to 60A to match the 8 AWG capacity
3. THHN is not permitted in residential attics
4. A 50A circuit requires a minimum of 6 AWG regardless of temperature
Show the answer
A. The wire gauge is too small after applying ambient temperature derating factors
When ambient temperatures exceed 86°F (30°C), NEC requires ampacity derating. 8 AWG THHN at 50A will fall below the required capacity when derated for 120°F (49°C).
Original practice question, written against published exam objectives. Open this question
When wiring a dual-voltage (230/460V) 9-lead 3-phase motor for high voltage (460V), how should the windings be connected?
1. In parallel
2. In a delta-only configuration
3. In a star-only configuration
4. In series
Show the answer
D. In series
For a dual-voltage motor, the windings are connected in series for the high-voltage application so that each winding receives its rated voltage.
Original practice question, written against published exam objectives. Open this question

Common questions

Are the questions based on a particular wiring standard?

International practice for low-voltage installations follows IEC 60364, and many questions reflect its principles. Check the advert, or ask the recruiting institution, whether a specific national standard applies, and study that edition.

Do I need to know three-phase systems for an electrician test?

Yes, at a basic level. Know the difference between line and phase voltage, what 400 V three-phase supplies are used for, and why loads are balanced across the phases.

How much of the test is practical knowledge rather than theory?

Many electrician questions describe real situations: a fault, a test result or a job to plan. Practical experience makes those questions much easier, so combine study with hands-on work wherever you can.