A simple guide to connectors

What are electrical connectors?

Electrical connectors are devices that join conductors, wires or cables, to create safe, reliable electrical pathways. At their core, they ensure current flows where it’s needed while allowing circuits to be extended, maintained, or disconnected without cutting or soldering. From the smallest appliance to the largest industrial control system, connectors are the invisible infrastructure that keep power and signals moving.

This connector guide will help you understand the basics of electrical connectors, their common types, and how to choose the right one for your application.

Where are they used?

Connectors appear in almost every electrical setting:

• Domestic installations - junction boxes, lighting circuits, appliance wiring.
• Commercial environments - office fit-outs, data cabling, HVAC systems.
• Industrial sites - control cabinets, machinery, factory automation.

In each case, the principle is the same: create a reliable, maintainable connection that meets both electrical and safety requirements.

Common types of connectors

Over the years, several connection methods have become standard:

• Screw terminals - A traditional choice, where wires are secured by tightening a screw onto a metal contact. Reliable but prone to loosening with vibration and requires tools.
• Terminal blocks (a.k.a. “choc blocks”) - Plastic housings with embedded metal contacts. Wires are clamped with screws, making them reusable but sometimes bulky.
• Lever connectors - Modern connectors (e.g. WAGO’s Lever-Nuts®) that use a simple lever mechanism to clamp wires securely without tools. Fast, reusable and vibration resistant.
• Push-in connectors - Wires are inserted directly into spring clamps, locking into place instantly. Ideal for speed and compact installations.

The choice to utilise WAGO connectors is a modern, data-driven decision. It is a shift from legacy methods that prioritise low component cost to a professional-grade solution that prioritises a reduction in both installation time and long-term risk. Ultimately, one chooses WAGO connectors for a profound improvement in workflow and an investment in a highly reliable, certified, and versatile system that delivers dividends through a faster, safer, and more profitable way of working.

Choosing the right connector

When selecting a connector, consider the following factors:

• Wire type and size - Solid, stranded and fine-stranded conductors behave differently; the connector must be rated for the correct cross-sectional area (mm² or AWG).
• Current load - The connector’s current rating should comfortably exceed the circuit demand.
• Installation environment - Heat, vibration, humidity, or limited space all influence the best choice.
• Assembly needs - Is tool-free installation a priority? Will the connection need to be reopened or altered?
• Compliance and safety - Always ensure the connector meets relevant standards (BS, IEC, UL) and is approved for the intended application.

For a deeper dive into specification, see Rapid’s guide to choosing the right cable - many of the same principles apply to connectors.

Why modern spring-clamp connectors are preferred

Lever and push-in connectors have rapidly gained popularity in professional settings because they solve common issues with screws and twists. Spring technology ensures constant pressure on the wire, so connections stay tight even under vibration. Transparent housings often allow quick inspection of proper insertion. Above all, they save significant time in installation and maintenance.

Spotlight: WAGO Connectors

WAGO is a pioneer in spring-clamp connection technology and has set the benchmark for tool-free wiring. Their product families are widely trusted in building services, industrial automation and transport due to their reliability and ease of use.

• 221 Series Lever-Nuts® - Compact, transparent housings available in 2-, 3- or 5-way options. Accept solid, stranded, or fine-stranded wires (0.14–6 mm²). Easy to reuse and feature test slots for inspection.

• 222 Series Lever-Nuts® - Robust connectors, vibration-resistant and ideal for more demanding installations including marine and rail. Handle up to 2.5 mm² conductors.
• PUSHWIRE® Connectors - Ultra-compact push-in designs like the 243 Micro and 2773 Wall-Nuts®. Perfect for low-voltage lighting, space-limited boxes, or quick terminations.

By choosing the right connector, whether screw, push-in or lever, you not only improve installation speed but also ensure long-term safety, reliability and compliance.