What are the wire colours in a UK plug?

The current UK wiring colours (harmonised with European standards since 2004) are: Brown for Live (L), Blue for Neutral (N), and Green/Yellow striped for Earth (E). The older UK colours were: Red for Live, Black for Neutral, and Green for Earth. The colour change was introduced by BS 7671:2004 (the 17th Edition) and BS EN 60446 to harmonise with the European colour code system. In a plug, you will almost always see the current colours (brown, blue, green/yellow) because flex cable has used the harmonised colours since the 1970s for new manufacturing. If you encounter a very old appliance with red, black, and green wires, the connections are the same: red (live) to the fused terminal, black (neutral) to the left terminal, and green (earth) to the top terminal.

How do I choose between a 3A and 13A fuse?

The rule of thumb is simple: use a 3A fuse for appliances rated up to 700W, and a 13A fuse for appliances rated over 700W. The fuse is there to protect the flex cable, not the appliance — it should blow before the cable overheats. Appliances that typically use a 3A fuse include: table lamps (60-100W), phone chargers (5-20W), radios (10-50W), televisions (50-200W), laptop chargers (30-90W), and small audio equipment. Appliances that typically use a 13A fuse include: kettles (2,200-3,000W), toasters (800-1,500W), irons (1,000-2,400W), fan heaters (1,000-3,000W), washing machines (2,000-2,500W), and vacuum cleaners (700-2,400W). Some appliances fall in the middle — a 700W microwave or a 700W vacuum cleaner could use either. When in doubt, check the rating plate on the appliance and choose the fuse that is just above the current draw: Power (W) / Voltage (230V) = Current (A).

Is it legal for a homeowner to wire a plug in the UK?

Yes. Wiring a 13A plug is not notifiable work under Part P of the Building Regulations and does not require an electrician. It is considered a simple maintenance task that any competent person can carry out. The plug is not part of the fixed electrical installation — it is part of the appliance or portable equipment. BS 1363 covers the design and safety requirements for 13A plugs, and there is no legal restriction on who can wire one. However, if the plug is wired incorrectly and causes an injury or fire, the person who wired it could be held liable. This is why it is important to follow the correct procedure, use the right fuse, and check the wiring before use.

Why does my plug get hot?

A hot plug usually indicates a poor connection inside the plug, an overloaded circuit, or a damaged flex. The most common cause is loose terminal screws — if the wire is not clamped tightly in the terminal, the connection has high resistance, which generates heat. Open the plug, check all three terminals are tight, and ensure the correct amount of copper is in each terminal. Other causes include: using a fuse that is too high for the appliance (allowing excessive current flow), a damaged or kinked flex cable (internal conductor damage), or a faulty appliance drawing more current than it should. If the plug continues to get hot after checking the connections, stop using the appliance and have it inspected by an electrician. A hot plug can melt the plug housing and cause a fire.

Do I need to connect the earth wire if my appliance is double-insulated?

Double-insulated appliances (marked with the double-square symbol on the rating plate) do not require an earth connection. The flex cable on a double-insulated appliance will only have two cores: brown (live) and blue (neutral). There is no earth wire to connect. If the plug came with the appliance and is moulded on, it will have a plastic earth pin (not connected internally). If you are fitting a new plug to a double-insulated appliance, connect only the brown and blue wires. The earth terminal should be left empty. Do not cut or remove the earth pin from the plug — it is needed to open the socket shutter mechanism on UK 13A sockets.

Can I use a European plug in the UK?

European 2-pin plugs (Type C/Europlug) are not compatible with UK 13A sockets (Type G, BS 1363). The pins are different sizes and the UK socket has shuttered entries that require the earth pin to open. Using a travel adaptor is the safest temporary solution, but for permanent use in the UK, the European plug should be replaced with a BS 1363 UK plug. When fitting a UK plug to a European appliance, check the voltage rating — most modern European appliances are rated 220-240V and will work on the UK 230V supply. If the appliance is rated 110V only, it will not work on the UK supply without a step-down transformer. Also check whether the appliance is double-insulated (2-core flex) or earthed (3-core flex) and connect accordingly.

HOW-TO GUIDE

How to Wire a Plug: Step-by-Step Guide for the UK

Brown is live, blue is neutral, green/yellow is earth. Use a 3A fuse for appliances up to 700W and 13A for everything above. This guide walks you through every step of wiring a UK 13A plug safely and correctly.

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8 min readUpdated 2026-05-18Andrew 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

1A UK 3-pin plug uses three wires: brown (live), blue (neutral), and green/yellow (earth). The earth wire connects to the top pin, live to the bottom right (with the fuse), and neutral to the bottom left.
2Use a 3A fuse for appliances rated up to 700W (table lamps, phone chargers, radios) and a 13A fuse for appliances rated over 700W (kettles, toasters, irons, heaters).
3The outer sheath of the flex must be clamped firmly by the cord grip inside the plug — this prevents the individual wires from being pulled out if the cable is tugged.
4Strip approximately 8mm of insulation from each conductor for terminal connection, and ensure no bare copper is visible outside the terminal.
5Elec-Mate includes a wiring reference library that electricians can share with clients — including plug wiring diagrams, fuse selection guides, and UK wiring colour charts.

01 · How-To Guide

Why You Should Know How to Wire a Plug

Wiring a 13A plug is one of the most basic electrical skills anyone can learn. While most new appliances come with moulded plugs already attached, there are still many situations where you need to fit or re-wire a plug: replacing a damaged plug, fitting a plug to an imported appliance, connecting a replacement flex to an older appliance, or rewiring a plug where the connections have come loose.

A correctly wired plug is safe. An incorrectly wired plug is dangerous — connecting the live wire to the earth terminal, or failing to secure the cord grip, can cause electric shock or fire. This guide follows the requirements of BS 1363 (the standard for UK 13A plugs) and explains every step clearly.

Understanding UK wiring colours is the foundation. Once you know which wire goes where and why, wiring a plug takes less than five minutes.

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02 · How-To Guide

What You Need

A BS 1363 UK 3-pin plug — the standard UK plug with three rectangular pins. Make sure it carries the BS 1363 kitemark.
A small flat-blade screwdriver — for the terminal screws and the plug cover screw.
Wire strippers — to remove insulation from the individual conductors. A sharp knife can be used carefully, but wire strippers are safer and more precise.
Side cutters — to trim wires to the correct length.
The correct fuse — 3A (red) or 13A (brown), depending on the appliance rating.

03 · How-To Guide

Wire Colours Explained

Brown = Live (L)

The live wire carries the current from the supply to the appliance. It connects to the bottom-right terminal in the plug — the terminal with the fuse holder next to it. This is the most dangerous wire. If you touch it while the plug is connected, you will receive an electric shock.

Blue = Neutral (N)

The neutral wire completes the circuit, carrying the current back to the supply. It connects to the bottom-left terminal in the plug. While the neutral is at or near zero volts under normal conditions, it should still be treated as potentially live — a fault in the installation could make the neutral live.

Green/Yellow = Earth (E)

The earth wire provides a safe path for fault current if the live wire touches the metal casing of the appliance. It connects to the top terminal — the largest pin. Under normal operation, no current flows through the earth wire. It only carries current during a fault, causing the fuse or circuit breaker to trip.

An easy way to remember: Brown = Bottom right, Blue = Bottom left. The earth (green/ yellow) always goes to the top, longest pin.

04 · How-To Guide

Step-by-Step: How to Wire a UK Plug

Remove the plug cover. Unscrew the single screw on the back of the plug and remove the cover. Note the positions of the three terminals and the cord grip.
Strip the outer sheath. Remove approximately 50mm of the outer sheath from the flex cable, exposing the three individual insulated conductors. Be careful not to nick the insulation on the individual wires.
Cut wires to length. Lay the flex in the plug with the outer sheath under the cord grip. Cut each wire to the correct length so it reaches its terminal without being too long or too short. The earth wire (top) should be the longest, the live wire (bottom right) should be the shortest.
Strip the insulation. Strip approximately 8mm of coloured insulation from the end of each conductor, exposing the bare copper.
Connect the earth wire (green/yellow). Insert the bare copper into the top terminal (marked E or with the earth symbol). Tighten the terminal screw firmly. No bare copper should be visible outside the terminal.
Connect the live wire (brown). Insert the bare copper into the bottom-right terminal (marked L). This is the terminal next to the fuse holder. Tighten the terminal screw firmly.
Connect the neutral wire (blue). Insert the bare copper into the bottom-left terminal (marked N). Tighten the terminal screw firmly.
Secure the cord grip. Position the outer sheath of the flex under the cord grip and tighten the cord grip screws. The cord grip must clamp the outer sheath — not the individual insulated wires. When you tug the cable, the cord grip should hold firm.
Insert the correct fuse. Push the fuse (3A or 13A) into the fuse holder clips next to the live terminal.
Replace the cover. Ensure no wires are trapped or pinched, then screw the back cover on securely.

05 · How-To Guide

Fuse Selection: 3A or 13A

The fuse in a UK plug protects the flex cable from overheating. It is not there to protect the appliance — most appliances have their own internal fuse or protection. The plug fuse should be rated just above the normal current draw of the appliance.

3A Fuse (Red)

For appliances rated up to 700W (approximately 3A at 230V).

Table lamps and floor lamps
Phone and tablet chargers
Laptop chargers
Radios and small audio equipment
Televisions (most models)
Electric blankets
Clocks and small electronics

13A Fuse (Brown)

For appliances rated over 700W (approximately 3A to 13A at 230V).

Kettles (2,200 to 3,000W)
Toasters (800 to 1,500W)
Irons (1,000 to 2,400W)
Fan heaters (1,000 to 3,000W)
Washing machines (2,000 to 2,500W)
Vacuum cleaners (700 to 2,400W)
Microwaves (700 to 1,200W)

To calculate the fuse needed: check the wattage on the appliance rating plate and divide by 230V. If the result is under 3A, use a 3A fuse. If it is between 3A and 13A, use a 13A fuse. Never use a fuse rated higher than 13A in a standard BS 1363 plug.

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06 · How-To Guide

Correct Strip Lengths

Outer sheath: Strip approximately 50mm from the end of the flex. This exposes enough of the individual wires to reach their terminals.
Individual wire insulation: Strip approximately 8mm from each conductor. The exact amount depends on the terminal type — enough copper should be inserted into the terminal that no bare copper is visible when the screw is tightened.
Wire lengths: Each wire should be cut to reach its terminal without excess slack. The earth wire is the longest (it goes to the top pin), the neutral is medium length (bottom left), and the live is the shortest (bottom right). This ensures that if the cable is pulled, the live wire disconnects first.

Too much stripped insulation exposes bare copper outside the terminal, creating a shock risk. Too little means not enough copper is in the terminal, creating a loose connection that can overheat. Aim for 8mm exposed copper — just enough to fill the terminal barrel.

07 · How-To Guide

Common Mistakes to Avoid

Wires in the wrong terminals. The most dangerous mistake. Brown (live) in the earth terminal means the metal casing of the appliance becomes live. Always double-check: brown = bottom right (with fuse), blue = bottom left, green/ yellow = top.
Cord grip not securing the outer sheath. If the cord grip is clamping the individual wires instead of the outer sheath, a tug on the cable can pull the wires out of the terminals. The cord grip must grip the round outer sheath.
Too much bare copper exposed. If bare copper is visible between the insulation and the terminal, there is a risk of contact between wires or with the plug casing.
Wrong fuse. Using a 13A fuse on a lamp with thin 0.5mm flex means the flex can carry dangerous current before the fuse blows. Use a 3A fuse for low- wattage appliances.
Loose terminal screws. A loose connection generates heat. Always tighten terminal screws firmly and give each wire a gentle tug to confirm it is secure.

08 · How-To Guide

Safety Checks After Wiring

Before plugging in and switching on, carry out these visual checks:

Each wire is in the correct terminal: brown (live) to the right (with fuse), blue (neutral) to the left, green/yellow (earth) to the top.
All three terminal screws are tight. Tug each wire gently — none should come loose.
No bare copper is visible outside any terminal.
The cord grip is clamping the outer sheath firmly. Pull the cable — the cord grip should hold.
The correct fuse is in place (3A for appliances up to 700W, 13A for over 700W).
No wires are trapped or pinched by the plug cover.
The back cover is screwed on securely and sits flush.

09 · How-To Guide

For Electricians: Teaching Clients the Basics

As a professional electrician, you will regularly encounter clients with questions about plug wiring, fuse selection, and appliance safety. Elec-Mate includes a client education library that you can share directly:

Client Reference Library

Share plug wiring diagrams, fuse selection guides, and UK wiring colour charts with your clients by WhatsApp or email. Professional-quality reference material with your branding.

PAT Testing Integration

If you carry out PAT testing for commercial clients, Elec-Mate records every appliance test, generates PAT test labels, and produces the register — all from your phone.

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Frequently Asked Questions About Wiring a Plug

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How to Wire a Plug: Step-by-Step Guide for the UK

Key Takeaways

Why You Should Know How to Wire a Plug

Get the BS 7671 A4:2026 Cheat Sheet — free

What You Need

Wire Colours Explained

Brown = Live (L)

Blue = Neutral (N)

Green/Yellow = Earth (E)

Step-by-Step: How to Wire a UK Plug

Fuse Selection: 3A or 13A

3A Fuse (Red)

13A Fuse (Brown)

Try Elec-Mate free for 7 days

Correct Strip Lengths

Common Mistakes to Avoid

Safety Checks After Wiring

For Electricians: Teaching Clients the Basics

Client Reference Library

PAT Testing Integration

The complete electrician's toolkit

Frequently Asked Questions About Wiring a Plug

What are the wire colours in a UK plug?

How do I choose between a 3A and 13A fuse?

Is it legal for a homeowner to wire a plug in the UK?

Why does my plug get hot?

Do I need to connect the earth wire if my appliance is double-insulated?

Can I use a European plug in the UK?

Continue reading

UK Wiring Colours Guide

PAT Testing Guide

Electrical Symbols Chart

Safe Isolation Procedure

RCD Keeps Tripping

Level 2 Electrical Course

What electricians say

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Fantastic app for electricians

Absolutely amazing

Trusted by electricians across the UK

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