Forked Terminals: Types, Sizes & How to Choose the Right One

Grab the wrong forked terminal at the wholesaler and you'll know about it at the panel — either the barrel won't crimp down on the wire, or the fork won't clear the stud. The red-blue-yellow colour system looks simple until you're staring at a product list with M3, M4, M5, and M6 options across three wire size ranges, two grip types, and both insulated and non-insulated versions. This article walks through how to match the right forked terminal to your wire, your stud, and your job.

What Is a Forked Terminal?

A forked — or spade — terminal is a crimp connector with an open-ended fork at the tip that slides over a threaded stud or screw without needing to remove the nut completely. That open slot is the difference between a ring terminal and a forked terminal: rings need the fastener fully out, forks just need it loosened. In practice, this makes forked terminals the go-to for terminals blocks, DIN rail-mounted equipment, switchboard busbars, and anywhere you expect to disconnect and reconnect under service conditions.

They're found across residential, commercial, and light industrial work — anywhere a TPS building wire lands on a terminal block or equipment stud. The termination is simple, but getting the spec right matters: an undersized barrel cracks under crimp pressure, an oversized fork rattles on the stud and creates a poor contact.

Colour Code: Red, Blue, Yellow — and Black

The insulation colour on a forked terminal tells you the wire size range the barrel is designed for. This system is consistent across most manufacturers, so once you know it you can order confidently from any supplier:

Note that wire size ranges overlap between colours — a 1.5mm² conductor sits in both red and blue range depending on the exact product specification. In practice, blue is the standard choice for 1.5mm² in most commercial and residential work. Always check the mm² range stamped or printed on the terminal packaging, not just the colour.

Stud Size: Matching the Fork to the Fastener

The stud size — M3, M4, M5, or M6 — refers to the metric thread diameter of the screw or bolt the terminal fork slides onto. This is determined by your equipment, not your wire. A terminal block might use M3 screws; a busbar connection might need M5 or M6. The fork slot must be wide enough to clear the stud but not so wide that the fork is loose on a smaller fastener.

In switchboard work, M4 is the most common stud size for terminal blocks and DIN rail equipment. M5 appears frequently on busbar connections and heavier equipment terminals. If you're not sure what size the equipment uses, measure the screw shank diameter — M4 is 4mm, M5 is 5mm across the thread.

Insulated vs Non-Insulated

Most forked terminals you'll handle are insulated — the barrel has a plastic sleeve that protects the crimped wire end and gives the colour coding you need to identify wire size at a glance. The insulation also provides a degree of protection against incidental contact on live terminals during commissioning, though it doesn't make the fork itself safe to touch when live.

Non-insulated forked terminals are used where the insulated sleeve would create a clearance issue — typically in compact equipment where there isn't enough room around the stud for the sleeve to clear adjacent components, or where the termination is fully enclosed within rated equipment. They're less common in general electrical work but are used in control panel builds and some industrial applications.

Grip Construction: Standard, Double Grip, and Supergrip

Standard forked terminals crimp the conductor only — the barrel grips the stripped wire, and that's it. For most fixed wiring applications where the termination isn't subject to vibration or repeated movement, that's sufficient.

Double grip terminals add a second crimp zone that grips the wire insulation behind the conductor crimp. This strain relief matters when the cable has any movement or tension — equipment panels where cables are bundled and pulled, or anywhere the termination might see mechanical load during service or maintenance. The DG suffix in product codes typically indicates double grip.

Supergrip is a variant grip construction that typically provides additional mechanical retention through a different barrel geometry — check the specific product for details, as construction varies between manufacturers. These are generally used in applications where pull-out resistance is a specific requirement.

Twin Forked Terminals

Twin forked terminals carry two wire barrels side by side on a single fork — the purpose is to land two conductors on the one stud without needing a separate dual-wire ferrule or piggyback arrangement. They're used in control panel work where two circuits need to share a common earth stud, or where equipment design calls for dual feed to one connection point. The fork size and wire size ranges follow the same colour code system as single terminals.

Common Mistakes

Picking the colour without checking the mm² range. Colour is a guide, not a guarantee. Two different manufacturers' red terminals can have slightly different barrel bore sizes within the 0.5–1.6mm² range. Check the exact wire size printed on the product — especially if you're mixing brands on the same job.

Assuming stud size from the terminal colour. Colour codes the wire, not the fork. Ordering a bag of blue M4 terminals and finding the equipment has M5 studs is a common one — especially on imported equipment where stud sizes don't always match what you'd expect from the circuit size.

Using standard grip on moving cables. In a static panel with well-dressed cable, standard grip works fine. On a hinged door with a cable loom flexing every time it opens, pulling on individual terminations over time — that's where a conductor-only crimp can work loose. It's the kind of fault that shows up six months later, not on commissioning day.

Ordering by colour only for a bulk job. If you're pulling 100 terminals for a board build, order by the full spec — colour, wire range, stud size, grip type, and pack size. Colour alone won't get you the right product when there are four stud sizes and three grip constructions available in each colour.

Crimping over the insulation sleeve. The barrel of an insulated terminal is designed to be crimped on the conductor section only. Running the crimp die over the plastic sleeve instead of or alongside the metal barrel doesn't create a secure connection — the sleeve compresses and springs back, leaving an unreliable contact. Strip to the right length so the conductor fills the barrel with minimal sleeve intrusion.

Frequently Asked Questions

Selecting the Right Terminal

Can I use a blue terminal on a 2.5mm² wire?

It depends on the specific product — some blue terminals are rated to 2.5mm² and some stop at 2.0mm² or 2.6mm². Check the wire size range on the product label or data sheet, not just the colour. For 2.5mm² TPS circuits, a yellow terminal rated from 2.5mm² upward is often the safer and more common choice. See the yellow M4 forked terminal as a starting point.

What's the difference between a forked terminal and a ring terminal?

A ring terminal fully encircles the stud — the fastener must be removed to install or remove the ring. A forked terminal has an open slot, so you only need to loosen the nut to slide the fork in or out. Forked terminals are faster to disconnect under service conditions; ring terminals are more secure where vibration is a concern and the connection is permanent or semi-permanent.

Licensing and Compliance

Do I need a licence to terminate wiring with forked terminals in a switchboard?

Yes. Switchboard wiring and termination work in Australia must be carried out by a licensed electrician. This applies regardless of the type of terminal used — forked, ring, or ferrule. Low-voltage control wiring within rated equipment may have different rules depending on the state and the specific application, but for any work connected to the mains electrical system, a licence is required.

Is there an Australian standard that specifies which terminal type to use?

AS/NZS 3000 (the Wiring Rules) sets the general requirements for electrical installations including termination quality and conductor securing, but it typically doesn't prescribe a specific terminal type for most applications — that's generally left to good workmanship and the equipment manufacturer's requirements. Where a specific terminal type is required, it will usually be called out in the equipment's installation instructions or a project specification.

Installation

Can I use the same crimp tool for insulated and non-insulated forked terminals?

Not always. Insulated terminals typically require a ratchet crimp tool with colour-coded dies (red, blue, yellow) that match the insulated barrel. Non-insulated terminals need an open barrel or hexagonal die. Using an insulated-terminal tool on a non-insulated terminal usually produces an uneven or incomplete crimp. Check your tool's die specifications before swapping between terminal types on the same job.

Do I need to use double grip terminals on a switchboard door with a cable loom?

It's good practice, and some panel builders specify it as standard. The cable loom on a hinged door flexes at every opening — over time, that repeated movement puts tension on individual terminations. Double grip terminals add insulation strain relief that resists pull-out from that kind of cyclic load. Whether it's a hard requirement depends on the panel specification — but it's rarely a wasted upgrade in a door loom application.

Shop Forked Terminals at Schnap

Trade pricing and same-day dispatch from Kingsgrove NSW. Stock covers red, blue, yellow, and black in standard, double grip, and supergrip constructions — M3 through M6 stud sizes, insulated and non-insulated options.

Red — 0.5–1.6mm²
Forked Spade Terminal 0.5–1.6mm² M4 Red — standard insulated, M4 stud
Forked Spade Terminal 0.5–1.6mm² M4 Red Double Grip — insulation strain relief, M4 stud

Blue — 1.0–2.6mm²
Forked Spade Terminal 1.5–2.5mm² M4 Blue Double Grip — standard choice for 1.5mm² and 2.5mm² TPS on M4 studs
Forked Spade Terminal 1.5–2.5mm² M5 Blue Double Grip — M5 stud, double grip
Forked Spade Terminal Insulated 1.0–2.6mm² M4 Blue — standard insulated, M4
Forked Spade Terminal Insulated 1.0–2.6mm² M5 Blue — standard insulated, M5
Forked Spade Terminal M4 Blue Pack of 100 (Repelec) — bulk pack option

Yellow — 2.5–6.0mm²
Forked Spade Terminal 2.5–6.0mm² M5 Yellow — standard insulated, M5 stud
Forked Spade Terminal 2.5–6.0mm² M5 Yellow Double Grip — strain relief, M5 stud
Forked Spade Terminal M4 Yellow Pack of 50 (Repelec) — bulk pack option

Black — 10mm²
Forked Spade Terminal 10mm² M5 Black — heavier sub-mains and motor connections

Non-Insulated
Forked Spade Terminal Non-Insulated 2.5–6.0mm² M5 — compact equipment and control panel applications

Twin Forked Terminals
Twin Forked Spade Terminal 1.5–2.5mm² M4 Blue — dual conductor on one stud
Twin Forked Spade Terminal 4–6mm² M4 Yellow — dual conductor, heavier gauge

Stock up on forked terminals at Schnap — everything you need in one place, dispatched same day from Kingsgrove.