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Bootlace ferrules and BS 7671

Updated: 21 October 2026

A 1,200-piece kit on amazon.co.uk can look as if every stranded cable in a UK house needs a sleeve. That is not what the Wiring Regulations ask. This page is when BS 7671 Regulation 526.9 points at a treated end, and when a bootlace ferrule is the wrong treatment. The pliers sit on the [crimping pliers set comparison](/hub/pliers/crimping-pliers-set). A qualifying purchase can earn us a commission at no extra cost to you. Fine strands need a suitable terminal or a treated end. A crimped ferrule is one treatment. A badly fitted one is worse than bare wire under the same screw.

A 1,200-piece kit on amazon.co.uk can look as if every stranded cable in a UK house needs a sleeve. That is not what the Wiring Regulations ask.

Our top picks

Preciva Preciva ferrule crimper set, 1,200 sleeves

Best overall

Preciva Preciva ferrule crimper set, 1,200 sleeves
9.4/10about £22.99
View offer
Preciva Preciva ferrule kit with twin sleeves

Alternative

Preciva Preciva ferrule kit with twin sleeves
9.4/10about £23.99
View offer
Hibisaws Hibisaws ferrule kit, 1,250 sleeves

Best value

Hibisaws Hibisaws ferrule kit, 1,250 sleeves
9.0/10about £19.99
View offer
On this page
  1. 1.What Regulation 526.9 actually asks for
  2. 2.Where a ferrule is the wrong treatment
  3. 3.Twin ferrules and collar colours
  4. 4.What this does not permit

What Regulation 526.9 actually asks for

The IET’s Wiring Matters mythbuster puts Regulation 526.9 in workshop English. Fine strands need a suitable terminal, or an end treated so the screw does not splay them. A bootlace ferrule, crimped before it meets the screw, is one treatment. The screw must not close an open tube. Regulation 526.1 asks the joint to stay tight without crushing the conductor. Torque follows the board maker, not the ferrule colour. None of that says you must buy 1,200 sleeves. On IET EngX, a loose or collar-crushed sleeve has not met 526.9. How to form the crimp sits on the how to crimp a bootlace ferrule page.

Where a ferrule is the wrong treatment

Solid twin and earth is not fine strand. Forcing a sleeve onto 2.5 mm² solid copper that will not sit in the tube does not make a designed terminal safer. Many UK lighting and socket circuits are solid. The kit is for flexible cord. Cage clamps and some lever terminals take fine strands without a ferrule. IET EngX is clear that a ferrule on large meter tails can be the wrong treatment. A 25 mm² tail with a loose sleeve is a dangerous extra. If the maker’s sheet says bare strands, follow that sheet. BS 7609, from 10 mm² copper, is not the standard for a 0.5 mm² bootlace kit.
Preciva Preciva ferrule crimper set, 1,200 sleeves

Testsieger

Preciva Preciva ferrule crimper set, 1,200 sleeves
9.4/10about £22.99
View offer

Twin ferrules and collar colours

A twin ferrule lets two conductors enter one terminal only when that terminal is designed for two conductors of that size. The Preciva twin-sleeve kit includes 260 dual-tube pieces. Two singles forced into one hole are a different joint. Collar colour is not a lookup table. DIN 46228-4, a French sequence, and a code UK sellers call German disagree with each other and with red, blue and yellow rings. An IET EngX post prints DIN 4662; catalogues say DIN 46228-4. Do not merge those numbers. Read the printed mm². A red ring and a green collar are not one size system. That split is the ferrule crimper or insulated terminal crimper page.

What this does not permit

A CE mark on the pliers is not a UKCA approval of the crimp and not evidence the joint meets BS 7671. We have not lab-tested these kits. Opening a consumer unit or dressing meter tails is electrician’s work. Buy a ferrule kit only for a treated flexible end, after the circuit is isolated or you are on an offcut. The die and the millimetre range sit in the crimping pliers set buying guide. If a cage clamp wants bare strands, leave the sleeve in the box. If a screw terminal on fine flex allows a ferrule, crimp the tube first, then torque to the stated figure.

Common questions

Are bootlace ferrules compulsory in a UK house?
No. Regulation 526.9 asks for a suitable terminal or a suitably treated end on fine strands. A properly crimped ferrule is one treatment. The IET does not say every stranded cable needs a sleeve.
Do I ferrule 2.5 mm² twin and earth?
Not if it is solid conductor into a terminal designed for it. Fine flex is the usual ferrule job. Solid twin and earth is a different cable. Read the conductor, not the room it sits in.
What about a cage clamp or a lever terminal?
Many of those terminals are designed for fine strands without a ferrule. Follow the maker’s sheet. A ferrule in a clamp that was not drawn for one can be the wrong treatment, especially on large tails.
Can I put two wires in one ferrule?
Only with a twin sleeve, and only if the terminal is designed for two conductors of that size. Two singles forced into one hole are not the same joint.
Why is the collar colour not red, blue and yellow?
Those three colours are the usual insulated-terminal bands. Ferrule collars follow other sequences, and those sequences disagree. Printed mm² wins. Do not read a green collar as if it were a yellow ring.
Should I ferrule the meter tails?
Not as a default. IET discussion treats large tails in a cage clamp as a bad place for a loose sleeve. Meter tails are electrician’s work. A £20 kit is not a method for that joint.
Who should do the consumer unit?
An electrician. Torque, device instructions and isolation sit with the person who will sign the work. This page does not permit opening a board on the strength of a ferrule kit.
Does CE on the pliers mean the crimp meets BS 7671?
No. CE on a listing is not our test and not a UKCA approval of the joint. Regulation 526.9 is met by a suitable terminal or a properly treated end, not by a mark on the handles.

Related pages

Ferrule pliers

Crimping pliers set

Best crimping tool kit for ferrules, rings or plugs

Crimping pliers set buying guide for household kits

Ferrule crimper vs insulated terminal crimper kits

How to crimp a bootlace ferrule without a half-cycle

Sources

Public UK sources from the research digest, last checked on 19 October 2026. Shelf prices and star lines are the amazon.co.uk figures in the display file.

  1. IET Wiring Matters: Mythbuster 5, terminal blocks and ferrules (retrieved 19 October 2026)
  2. IET EngX: Ferrule crimps (retrieved 19 October 2026)
  3. IET EngX: Crimping of flexible cord conductors (retrieved 19 October 2026)
  4. BSI: BS 7609:1992+A2:2009, uninsulated power connectors (retrieved 19 October 2026)
  5. HSE: Electricity at Work Regulations guidance, HSR25 (retrieved 19 October 2026)
  6. RS: Bootlace ferrules (retrieved 19 October 2026)
  7. RS: Knipex 97 53 04 crimp tool (retrieved 19 October 2026)
  8. Klauke GB: Insulated solderless terminals (retrieved 19 October 2026)