What topics are covered in Year 1 of an electrical apprenticeship?

Year 1 of a Level 3 Electrical Installation apprenticeship covers fundamental electrical theory including electrical units (volts, amps, ohms, watts), Ohm's Law, Kirchhoff's Laws, series and parallel circuits, DC and AC fundamentals, basic tools and their safe use, health and safety legislation (Health and Safety at Work Act 1974, Electricity at Work Regulations 1989), PAT testing introduction, and basic wiring principles. You will also begin working towards your Level 3 Award in the Requirements for Electrical Installations (BS 7671).

How do I revise Ohm's Law effectively?

Use the Ohm's Law triangle (V at the top, I and R at the bottom). Cover the unknown and the remaining symbols show you the formula: cover V → V = I × R; cover I → I = V / R; cover R → R = V / I. Practice transposing the formula with worked examples until it becomes automatic. The Elec-Mate flashcard system lets you drill Ohm's Law calculations with randomly generated values so you practise the maths, not just the formula.

What is the difference between series and parallel circuits?

In a series circuit, components are connected end-to-end so the same current flows through every component. The total resistance is the sum of all individual resistances (Rt = R1 + R2 + R3). Voltage is shared between components proportional to their resistance. In a parallel circuit, each component has its own separate path connected between the same two points. The voltage across each branch is identical, but current divides between branches. Total resistance in a parallel circuit is always less than the smallest individual resistance.

What is the UK mains supply voltage and frequency?

The UK nominal supply voltage is 230V AC at 50Hz (hertz). The voltage tolerance is +10% / -6%, meaning acceptable voltages range from approximately 216.2V to 253.0V. The frequency tolerance is ±1%, so 49.5Hz to 50.5Hz. These limits are set by the Electricity Safety, Quality and Continuity Regulations (ESQCR) and align with European harmonised voltages. You must know both values — they appear frequently in theory exams and practical assessments throughout your apprenticeship.

What health and safety legislation must I know in Year 1?

The key legislation for Year 1 includes: Health and Safety at Work etc. Act 1974 (HSWA) — the primary legislation placing duties on employers and employees; Electricity at Work Regulations 1989 — specific to electrical systems, requires all electrical work to be carried out in a safe manner; Manual Handling Operations Regulations 1992 — risk assessment for lifting and moving loads; Personal Protective Equipment at Work Regulations 1992 — employer duty to provide PPE; and Control of Substances Hazardous to Health Regulations 2002 (COSHH). In construction, you will also encounter the Construction (Design and Management) Regulations 2015 (CDM).

What tools should a first-year apprentice know?

First-year apprentices should be able to identify, name, and use correctly: screwdrivers (flathead, Pozidriv, insulated), wire strippers, cable cutters, pliers (combination, long-nose), hammer, chisel, cold chisel, spirit level, tape measure, bradawl, cordless drill, and voltage indicator. You must also understand when and how to use PPE including insulated gloves, safety glasses, hard hat, steel-toecap boots, and hi-vis vest. Never use a tool you have not been trained on — always ask your supervisor.

What is PAT testing and do apprentices do it?

PAT stands for Portable Appliance Testing — the process of inspecting and testing portable electrical equipment to check it is safe to use. Apprentices are introduced to PAT testing in Year 1 as it demonstrates fundamental principles: visual inspection, earth continuity testing, insulation resistance testing, and record keeping. Formal PAT testing certification (City & Guilds 2377) is usually completed later in the apprenticeship or after qualification, but understanding the principles from Year 1 helps build inspection and testing skills that are central to the AM2 assessment and EICR work.

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Electrical Apprentice Year 1 Revision: First Year Study Guide

Everything you need to revise for Year 1 of your electrical apprenticeship — electrical units, Ohm's Law, series and parallel circuits, DC and AC fundamentals, basic tools, health and safety legislation, and an introduction to PAT testing.

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12 min readUpdated 2026-06-10Andrew Moore, Founder of Elec-Mate

Written and reviewed by Andrew Moore, founder of Elec-Mate, against BS 7671:2018+A4:2026, IET Guidance Note 3 and the IET On-Site Guide.

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Key Takeaways

1Ohm's Law (V = IR) is the single most important formula in Year 1 — know it forwards, backwards, and be able to transpose it for any unknown.
2The six core electrical units you must memorise: volt (V), ampere (A), ohm (Ω), watt (W), coulomb (C), and farad (F).
3Series circuits share the same current throughout; parallel circuits share the same voltage across each branch.
4AC (alternating current) in the UK runs at 230V / 50Hz — frequency and voltage values appear in every exam.
5Health and safety legislation you must know in Year 1: Health and Safety at Work Act 1974, Electricity at Work Regulations 1989, and Manual Handling Operations Regulations 1992.
6BS 7671:2018+A4:2026 introduced two key rules apprentices encounter from day one: Reg 411.3.4 requires 30 mA RCD protection on domestic lighting circuits; Reg 421.1.7 recommends arc fault detection devices (AFDDs) on AC final circuits.

01 · Apprentice Study Guide

Electrical Units You Must Know

Before you can understand any electrical circuit, you need to know the units used to measure electrical quantities. These are the foundation of everything else in Year 1 and beyond. The International System of Units (SI) is used throughout electrical engineering.

Volt (V) — the unit of electromotive force (EMF) or potential difference (PD). Think of voltage as the electrical pressure that drives current around a circuit. Symbol: V. Named after Alessandro Volta.
Ampere (A) — the unit of electric current. Current is the rate of flow of electric charge. One ampere equals one coulomb of charge passing a point per second. Symbol: A or I (for intensity). Named after André-Marie Ampère.
Ohm (Ω) — the unit of electrical resistance. Resistance is the opposition to the flow of current. Symbol: Ω (omega) or R. Named after Georg Simon Ohm. One ohm is the resistance that allows one ampere to flow when one volt is applied.
Watt (W) — the unit of electrical power. Power is the rate at which energy is transferred or converted. Symbol: W or P. Named after James Watt. P = V × I (power equals voltage multiplied by current).
Coulomb (C) — the unit of electric charge. One coulomb is the charge transported by one ampere in one second. Q = I × t (charge equals current multiplied by time).
Farad (F) — the unit of electrical capacitance. Capacitance is the ability to store electrical charge. In practice, capacitors are measured in microfarads (μF) or picofarads (pF) as one farad is very large. Named after Michael Faraday.

You also need to understand SI prefixes for when values are very large or very small. The key prefixes in electrical work are: kilo (k) = 1,000; mega (M) = 1,000,000; milli (m) = 0.001; micro (μ) = 0.000001. So 2.5kΩ means 2,500 ohms, and 100mA means 0.1 amperes.

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02 · Apprentice Study Guide

Ohm's Law

Ohm's Law is the single most important relationship in electrical theory. Stated by Georg Simon Ohm in 1827, it defines the relationship between voltage, current, and resistance in a conductor at constant temperature.

The formula: V = I × R — Voltage (volts) equals Current (amperes) multiplied by Resistance (ohms).
Transposed for current: I = V ÷ R — if you know the voltage and resistance, divide voltage by resistance to find current.
Transposed for resistance: R = V ÷ I — if you know the voltage and current, divide voltage by current to find resistance.

Worked example: A 12V battery supplies a lamp with a resistance of 6Ω. What current flows? I = V ÷ R = 12 ÷ 6 = 2A. The Ohm's Law triangle is a memory aid: draw a triangle with V at the top, I bottom-left, R bottom-right. Cover the unknown quantity and the visible symbols show you the calculation.

Use the Elec-Mate Study Centre flashcard system to drill Ohm's Law calculations with randomly generated values until the transposition is second nature.

03 · Apprentice Study Guide

Basic Circuit Theory

Every electrical circuit has the same basic components: a source of EMF (battery or supply), conductors (wires) to carry current, a load (device that uses the energy), and a return path. Kirchhoff's Laws describe how voltage and current behave in circuits.

Kirchhoff's Current Law (KCL) — the total current entering a junction equals the total current leaving it. No current is lost at a junction. This is a statement of conservation of charge.
Kirchhoff's Voltage Law (KVL) — the sum of all voltages around a closed loop equals zero. In practice: the supply voltage equals the sum of all voltage drops across the resistances in the loop.
Series circuits — total resistance Rt = R1 + R2 + R3. Current is the same throughout. Voltage divides proportionally to resistance (voltage divider).
Parallel circuits — voltage is the same across every branch. Current divides between branches. For two resistors: 1/Rt = 1/R1 + 1/R2. Total resistance is always less than the smallest individual resistance.

04 · Apprentice Study Guide

DC Circuits

Direct current (DC) flows in one direction only. Batteries, solar panels, and USB chargers all produce DC. Understanding DC circuits is the foundation before moving on to AC, which is more complex due to the effects of inductance and capacitance.

Resistors in series: Rt = R1 + R2 + R3. Example: 10Ω + 15Ω + 25Ω = 50Ω total.
Resistors in parallel (two): Rt = (R1 × R2) ÷ (R1 + R2). Example: 6Ω and 12Ω in parallel = (6 × 12) ÷ (6 + 12) = 72 ÷ 18 = 4Ω.
Power in DC circuits: P = V × I, P = I² × R, P = V² ÷ R. All three are equivalent — use whichever suits the values you have been given.
Energy: W = P × t (energy in joules equals power in watts multiplied by time in seconds). For kilowatt-hours: kWh = kW × hours.

Practise these calculations using the apprentice module calculator tools in the Elec-Mate Study Centre. Working through multiple examples is far more effective than re-reading your notes.

05 · Apprentice Study Guide

AC Fundamentals

Alternating current (AC) repeatedly reverses direction. The UK mains supply is 230V at 50Hz — this is what you work with in almost every domestic and commercial installation. AC introduces concepts of frequency, period, peak values, and RMS values.

Frequency (f) — the number of complete cycles per second, measured in hertz (Hz). UK mains: 50Hz. USA mains: 60Hz.
Period (T) — the time for one complete cycle. T = 1 ÷ f. At 50Hz: T = 1 ÷ 50 = 0.02 seconds (20 milliseconds).
Peak value — the maximum voltage reached during a cycle. For UK mains (230V RMS): Vpeak = 230 × √2 ≈ 325V. This is why cable insulation must be rated for higher than the nominal supply voltage.
RMS (Root Mean Square) — the effective value of AC that produces the same heating effect as an equivalent DC voltage. The 230V on the nameplate of your socket outlet is the RMS value. Vrms = Vpeak ÷ √2.
Three-phase supply — commercial and industrial premises are supplied with three-phase 400V AC (line-to-line) / 230V (line-to-neutral). The three phases are 120° apart. You will study three-phase in depth in Years 2 and 3.

New in BS 7671:2018+A4:2026

Reg 411.3.4 — 30 mA RCD on domestic lighting circuits (mandatory): All AC final circuits supplying luminaires in domestic (household) premises must now have additional protection by an RCD with a rated residual operating current not exceeding 30 mA. This is a mandatory “shall” requirement — not guidance.
Reg 421.1.7 — Arc Fault Detection Devices (AFDDs) recommended: BS 7671 A4:2026 recommends the installation of AFDDs on AC final circuits to mitigate the risk of fire from arc fault currents. The wording is advisory rather than mandatory, but you will encounter AFDDs on new and rewired installations from day one.

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06 · Apprentice Study Guide

Basic Electrical Tools

Knowing how to select, use, and maintain tools safely is tested in the practical elements of your apprenticeship from Day 1. Your employer and college will both expect you to handle tools confidently and safely.

Screwdrivers — flathead for slotted screws, Pozidriv (PZ2 is most common) for cross-head screws. Insulated screwdrivers are rated to 1000V and required for live working. Never use a damaged or incorrect screwdriver as it can slip and cause injury or damage.
Wire strippers — used to remove cable insulation without nicking the conductor. Set to the correct cable diameter to avoid damaging cores. Quality wire strippers have adjustable stops for different cable sizes.
Pliers — combination pliers for gripping and cutting, long-nose (needle-nose) for accessing confined spaces and shaping wire. Always use insulated-handle pliers when working near live conductors.
Voltage indicator — a non-contact or two-pole voltage tester used to confirm a circuit is dead before working on it. Under the Electricity at Work Regulations 1989 and GS38, two-pole voltage testers are the industry standard for safe isolation. A non-contact tester alone is not sufficient confirmation that a circuit is dead.
Drill and bits — cordless drills are standard. SDS drills for masonry. Always check for hidden cables and pipes before drilling using a cable and pipe detector. Follow safe drilling procedures and wear eye protection.

07 · Apprentice Study Guide

Health and Safety Fundamentals

Health and safety is not just a box-ticking exercise — it is a legal requirement and a professional responsibility. Electrical work can be fatal if safety procedures are not followed. The following legislation is examinable in Year 1 and applies to your work every day.

Health and Safety at Work etc. Act 1974 — the primary UK health and safety legislation. Places a duty on employers to provide a safe working environment, safe equipment, and adequate training. Employees must take reasonable care for their own safety and the safety of others, and must co-operate with their employer on health and safety matters.
Electricity at Work Regulations 1989 — specific to electrical systems. Regulation 4 requires that electrical systems be constructed and maintained to prevent danger. Regulation 14 prohibits working on or near live conductors unless it is unreasonable to work dead, adequate precautions are taken, and it is reasonable to work live. Safe isolation is mandatory before working on any circuit.
Manual Handling Operations Regulations 1992 — requires employers to avoid manual handling where possible and, where not, to assess and reduce the risk. Electricians regularly handle cable drums, consumer units, and conduit that can cause musculoskeletal injury if handled incorrectly.
PPE at Work Regulations 1992 — employers must provide suitable PPE free of charge. Employees must use PPE correctly and report defects. Basic electrical PPE includes: safety footwear (steel toecap, anti-static), hi-vis vest, hard hat (on construction sites), safety glasses, insulated gloves, and hearing protection when using power tools.

Safe isolation is one of the most critical procedures you will learn. The sequence is: identify the circuit, switch off, lock off (lock the isolator and retain the key), attach a warning notice, test for dead using a proved voltage tester. Prove the tester works on a known live source before and after testing for dead. This prove–test–prove method is the GN3-aligned approach set out in Guidance Note 3, Chapter 8 (Reg 8.2): “isolation shall be established and proven before live-work tests are performed; voltage indicators shall be used.” A non-contact tester alone is never sufficient — always use a two-pole voltage indicator as your primary confirmation tool.

08 · Apprentice Study Guide

Introduction to PAT Testing

Portable Appliance Testing (PAT) is the process of inspecting and testing portable electrical equipment to ensure it is safe to use. While apprentices are not usually expected to carry out formal PAT testing independently in Year 1, understanding the principles is part of the syllabus and introduces key concepts in inspection and testing that become central to your work in later years.

Visual inspection — always the first step. Check for damaged cables, cracked plugs, signs of overheating, incorrect fuse rating, and evidence of misuse. Many faults are found by visual inspection alone, before any electrical testing is carried out.
Earth continuity test — checks that the earth conductor in the appliance is connected and has a low resistance. Typically less than 0.1Ω plus the resistance of the supply lead. Carried out using a PAT tester or a low-resistance ohmmeter.
Insulation resistance test — applies 500V DC between live conductors and earth. For Class I appliances, the insulation resistance should be at least 1MΩ (megohm). Confirms that the insulation has not broken down.
Record keeping — every PAT test must be recorded with the appliance description, asset number, test results, pass or fail outcome, date, and tester's name. Records demonstrate that a system of inspection and testing is in place and form the audit trail for workplace safety compliance.

The City & Guilds 2377 Award in the In-Service Inspection and Testing of Electrical Equipment is the recognised PAT testing qualification. Most apprentices complete this during their training or in the early years after qualification.

09 · Apprentice Study Guide

Elec-Mate Study Tools for Year 1 Apprentices

Elec-Mate has been built by electricians for electricians and apprentices. The Study Centre contains tools specifically designed to help you pass Year 1 theory and build the practical knowledge you need for your end-point assessment.

Flashcard Revision System

Drill Ohm's Law, electrical units, circuit theory, and health and safety legislation with the Elec-Mate flashcard system. Spaced repetition ensures you review cards at the optimal time before your exam.

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Ask the Elec-Mate AI tutor any question about Year 1 theory. Get step-by-step explanations of calculations, worked examples, and plain-English explanations of complex topics like AC waveforms and circuit analysis.

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Frequently Asked Questions About Year 1 Electrical Apprenticeship

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Electrical Apprentice Year 1 Revision: First Year Study Guide

Key Takeaways

Electrical Units You Must Know

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Ohm's Law

Basic Circuit Theory

DC Circuits

AC Fundamentals

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Basic Electrical Tools

Health and Safety Fundamentals

Introduction to PAT Testing

Elec-Mate Study Tools for Year 1 Apprentices

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AI Tutor

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Frequently Asked Questions About Year 1 Electrical Apprenticeship

What topics are covered in Year 1 of an electrical apprenticeship?

How do I revise Ohm's Law effectively?

What is the difference between series and parallel circuits?

What is the UK mains supply voltage and frequency?

What health and safety legislation must I know in Year 1?

What tools should a first-year apprentice know?

What is PAT testing and do apprentices do it?

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Maths for Electrical Apprentices

End-Point Assessment (EPA) Guide

Career Progression After Your Apprenticeship

City & Guilds Level 3 Guide

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