Order Relay Boards Online - Fast Local Stock for Makers & Engineers

Order relay boards online with confidence

Find the right relay boards for your project quickly - whether you're a student building lab demos, a maker automating a workshop, or a technician integrating control panels. Communica stocks a wide range of relay modules and boards from popular brands and maker-friendly suppliers, with practical advice on compatibility, power, and wiring so you spend less time troubleshooting and more time building. Shop Now

Why order relay boards from a local supplier?

• Immediate availability and branch pickup - check stock in Samrand or collect from our Pretoria or Cape Town branches to avoid long lead times. Branches & Trading Hours
• VAT invoices and account quotes for tertiary projects and procurement teams - simplified ordering for education and industry. relay-boards-quote
• Practical compatibility guidance for common controllers (Arduino, Raspberry Pi, ESP32) and industrial PLC interfaces.

Common relay board types and specification callouts

When you order relay boards online, check these specs first: coil voltage, contact rating (AC/DC), number of channels, isolation (optocoupler or direct drive), and form factor. For a broad selection, browse our category pages and brand listings. Shop by Category | Shop by Brand

Compatibility and accessory guidance

• Controllers: Use level-shifting or driver transistors for 12V coils when controlling from 3.3V boards like Raspberry Pi.
• Flyback protection: Confirm boards include diodes for DC coils; if not, add a diode across the coil.
• Accessories: Consider terminal blocks, DIN-rail mounts, screw connectors, and fuse holders to build a safe panel. Explore related products in our full index. All Products

Compare Specs to avoid returns - Compare Specs

Quick selection guide and wiring examples

Select the right relay board by mapping load current and control voltage. Use the formula below to size contacts and fuses correctly:

Simple calculations

Ohm's law and power: V = I × R; P = V × I. For AC loads, use the RMS voltage and allow a safety margin of 25-50% on contact ratings for inductive loads such as motors or solenoids.

Example: sizing a relay for a 230V motor

If motor inrush is 30A and running current 6A, choose a relay with an AC contact rating exceeding 30A or use a contactor/SSR designed for motor loads. Add appropriate fusing and thermal protection.

Basic wiring ASCII diagram (single channel)

Controller GPIO -----[DRIVER]-----+ Relay Coil
                                    |
                                   GND

Mains Live -----[Relay NO]----- Load ---- Neutral

For multi-channel and safety-critical installations follow good practices: separate mains wiring, secure terminals, and clearly labelled wiring. If you need hands-on help, our team and branch staff can advise on selection for educational and industrial projects - learn more about Communica's history and values. About Us

Troubleshooting common issues

• Relay not switching: check coil voltage, ground reference, and driver transistor orientation.
• Contacts weld: likely undersized for inrush - upgrade relay or fit an appropriate contactor.
• False triggering: add pull-down resistors or optoisolation for noisy environments.

Objection handling: If you worry about lead times, we publish stock status online and offer branch pickup in Samrand, Pretoria CBD, and Cape Town to minimise delays. For bulk purchases, Request a Quote and receive formal VAT invoices and account support for tertiary or procurement teams. Check Stock in Samrand

Why Communica is the practical choice

We combine deep component ranges with local service - thousands of SKUs across semiconductors, connectors, power modules and maker-friendly boards - so you can find compatible relay modules, driver accessories and enclosure options in one place. Our product pages and collections make Compare Specs straightforward and our branches help with immediate collection or technical advice.

Ready to order relay boards online? Whether you need a single 5V relay module for a lab project or a multi-channel industrial relay for a control panel, Communica provides stock visibility, specification support, and local collection options. Shop Now | Check Stock in Samrand | Compare Specs | Request a Quote