Sonoff SV WiFi AC/DC Switch: Installation Guide for Beginners

Step-by-step Sonoff SV WiFi AC/DC switch installation guide for South African makers. Wiring, configuration, safety, examples, and procurement tips.

Published:December 11, 2025

5 min read

Image supplied by 123RF

Safe low-voltage switching

Use the Sonoff SV for 5-24V DC loads and pair with external relays for mains.

Practical wiring guide

Follow polarity checks, fuse recommendations, and the ASCII wiring diagram.

Local procurement tips

Check Communica stock, request VAT invoices and collect from Samrand or branches.

Overview: What the Sonoff SV is and where to use it

The Sonoff SV WiFi AC/DC switch is a small, low-cost relay module designed to switch low-voltage DC loads and-to a limited extent-AC loads when used with an appropriate external power source. This guide covers practical installation, wiring diagrams, basic configuration, and tips for safe use in South Africa. The primary keyword "sonoff sv wifi acdc switch installation guide for beginners" appears throughout to help you find step-by-step instructions and troubleshooting advice.

Typical applications

Controlling 5-24V DC devices such as LED strips, small motors (via driver), or relays.
Integrating with home automation platforms for remote control and scheduling.
Educational projects and prototypes in labs or maker spaces.

Key specifications at a glance

Spec	Typical value
Input supply	5-24V DC (check module marking)
Logic / WiFi	ESP8266-based WiFi control
Relay rating	Small DC loads; avoid switching high AC mains directly

Note: The Sonoff SV is designed for low-voltage switching. If you need to control AC mains, pair the SV with a suitably rated relay or contactor and ensure compliance with local wiring practices.

What you need before you start

Sonoff SV module and suitable DC power supply (5-24V DC) sized to your load.
Small screwdrivers, multimeter, insulated jumper leads, and optionally a removable fuse in the supply line.
Smartphone on the same 2.4GHz WiFi network for initial configuration.
Where available, check stock and pick up parts from your local Communica branch: All products or browse IoT/relay sections at Collections.

Safety and South Africa-specific considerations

When working on electrical projects in South Africa, consider lead times, VAT invoicing for educational procurement, and branch collection options. Communica provides stock across branches-confirm availability and collect from Samrand or other branches: Branches & Trading Hours. For tertiary or classroom purchases, request VAT invoices or a quotation through Communica's accounts process; this helps with procurement records and budget approval.

Precautions

Always isolate mains power when modifying or mounting the module into an enclosure.
Use a fuse and a correctly rated external relay when switching mains; do not switch high AC currents directly through the Sonoff SV's relay contacts unless the datasheet confirms suitability.
Verify polarity and voltage with a multimeter before connecting the module.

Basic wiring and configuration

The Sonoff SV expects a DC supply and provides a switched output. Below is a common wiring scenario for switching a 12V LED strip using the SV with a 12V adapter.

ASCII wiring diagram: 12V LED strip example

 +12V DC Adapter (+) ----+----> Vin on Sonoff SV
                          |
                          +----> +12V input on LED strip

 GND (0V) ---------------+----> GND on Sonoff SV
                          |
                          +----> - (LED strip common)

 Sonoff SV switched output (Vout) ----> LED strip control input (if wired as switch)

(Optional) Sonoff SV relay contact in series with LED negative if configured that way.

Exact terminal labels may vary by module revision; consult the silkscreen on the board. After wiring, power the DC adapter, and follow the manufacturer's app pairing flow or flash alternative firmware if you prefer local control.

Configuration tips

Use a 2.4GHz WiFi network for pairing-the ESP8266 does not support 5GHz-only networks.
For classroom or lab installs, note WiFi SSID/password changes and consider reserved IPs or local MQTT to avoid reconfiguration after DHCP renewals.
Where students need multiple units, check volume availability and brand options at Shop by Brand.

Selection criteria: choosing the right Sonoff SV setup

When selecting a Sonoff SV and accessories, consider input voltage range, relay contact ratings, enclosure size, and whether you need an external relay for mains switching. For spare parts and accessories such as enclosures, screw terminals or DC adapters, review Communica's related categories: Collections and the general product index at All products.

Spec comparison table

Feature	Sonoff SV	Recommended addition
Supply voltage	5-24V DC	DC adapter with adequate current and fuse
Switching	Low-voltage DC loads	External mains relay/contactor for AC

Basic calculations and checks

Estimate the current draw of your load and ensure the power supply can deliver it. Use Ohm's law as a basic check:

V = I × R (Voltage = Current × Resistance)

If you know the voltage and wattage, current I = P / V. Example: a 12V LED strip rated at 24W draws I = 24W / 12V = 2A. Choose a DC adapter rated slightly higher (e.g., 3A) and add inline fuse rated to protect wiring (for example, 2.5A slow-blow as an estimate; confirm with your kit).

Troubleshooting checklist

No WiFi pairing: ensure 2.4GHz SSID, temporarily disable guest isolation or captive portals on the router.
Module won’t switch load: verify DC supply voltage and polarity, check relay solder joints and terminal connections with a multimeter.
Intermittent control: check WiFi signal strength; consider adding a small external antenna or repositioning the module within an enclosure that does not block RF.

Practical South African examples

For a university lab in Pretoria, procuring 10 Sonoff SV units and DC adapters might require a purchase order. Use Communica's branches for collection to save on delivery times-Samrand often holds warehouse stock, but confirm lead times and request a VAT invoice when placing the order. For small maker projects, you can reserve parts online and choose in-store pickup at the Pretoria CBD or Cape Town branches; see About Us for branch background and service notes.

Next steps and resources

After installation, consider local automation setups using MQTT or Home Assistant for classroom demonstrations. If you need other components such as enclosures, connectors, or test tools, search the Communica collections and product pages. For procurement help and quotes, request a formal quote if buying in bulk to include VAT invoicing and delivery options.

Sources

Very friendly and helpful; and a wide selection of items (at their location). You can also purchase via their WebSite; I have never been disappointed...

Review for Communica Samrand Security Wanted to share a heartfelt thank you to the security team at Communica Samrand! Yesterday, I had a personal ex...

Quick service from Layla and her team in providing technical assistance and getting my order together. This is the best service I have received in a l...

Fantastic service! Avi recommended Ajax and it has literally changed my life. Its not only a superb alarm system but it sports home automation to boot...

Needed help with network cameras and cables - Salesperson was extremely knowledgable and very friendly!! Helped me quickly - then the Technician even ...

Wide range of products, excellent service and friendly staff. Well informed and Layla also informed me on compatibility of the components I was about ...

I have a weird project with weird stuff I needed and Cynthia was super helpful and patient with me searching and deciding on what to get. Awesome serv...

I have been buying from Communica for many years now, since they were originally situated in Mooi street in Braamfontein. In general they have friendl...

Thy have a wide range of components. Thy do have a q to wait in but 1 come 1 serve. But while you wait thy have very cool stuff to look at you will al...

From warm welcome by the security check when you enter the store to sales man, then all the way to ladies behind the counter, one of them even organi...

Very pleased with the service from layla and nicole they were extremely helpful and full of smiles... Thank you ladies keep those bright spirits shini...

Any electronic parts available, chargers, batteries, camera and security stuff and mega big store. One of my favorite places to go with helpfull frien...

Excellent customer service all the way! Amazing, welcoming and energetic staff, especially Steven, Sydney and Nicole. This company is the gold standar...

Well organised store, excellent system of service and short waiting period. Staff (Nicole) was very helpful and passionate about the company, it very ...

What an absolute gem Layla is! She went out of her way to source my requested items from another branch, without me asking, and done so with a great b...

I had a fantastic experience at Communica, thanks to the exceptional service provided by Rehaan in sales and Nicole at the cashier. Rehaan was incredi...

Got assisted by a very patient and diligent gentleman by the name Sydney. He was patient in getting me what I needed from the little information I gav...

The kind gentleman right behind the turnstiles at the entrance sales counter helped me immediately as I walked in, Sydney, I think. I needed 8 packs o...

Rehaan was very helpful. He walked woth me through the store and assisted me to get all the items I needed. He also referred me to places that could h...

Amazing services Rehaan is the best, just ask for him. Just excellent service. You may end up buying more things than you had planned though. But it ...

I had a fantastic experience with Communica. Whenever I need electronics on short notice, their sales and logistics team always goes the extra mile to...

Can i give Fatima her flowers.... 10 000 out of 100. Customer service-100% Patience-100% Product knowledge-100% Had the best shopping experience there...

Good service good people great customer care never disappoint me when I'm looking for anything in need always smiling and welcoming...this time when I...

My special appreciation to Windie, with her super customer service. Keep up the good work my sister. Individuals like you gives us more peace to retur...

Fantastic service and help received by Nicole. Communica in general has amazing range of products and solutions to meet my business and personal needs...

After searching for a product on the net, Communica was one of several hundred suppliers found. I couldn't be more pleased with my decision to choose...

Sydney was an awesome help, he approached as we walked in for assistance. Nicole was such a darling and very helpful as well. Awesome first time exper...

Ordered online, was just after 6am. Asked if I can pick items up as I wanted to install over the weekend and delivery stated 2-4 working days. Though...

Online support and communication is next level - great communication, fast response - very helpfull, recomended supplier - online payment was no hasse...

At the till we met Nicole, First of her name! The rightful heir to the iron throne! the Unburnt, Breaker of Chains and pillar of strength at Communic...

Rehaan was the sales representative that helped us. He was friendly and helped us with in seconds. We where very pleased with the service and the expe...

I purchased the TP-LINK VIGI C340 4MM camera online... What an amazing camera. Easy to setup with long distance view, and superb quality. This was an ...

Online service is extremely great.. Had an amazing chat with one of the online chat consultants. Gave me info I needed, and we talked about my passion...

Lovely lady serving me named Nicole and I got very good assistance from Leburu on th floor whom directed me toward the correct goods. Will visit again...

I met Leburu and Nicole at the shop, Leburu took me to the right place with a great smile, then took me with my stuff to cashier Nicole where I paid a...

Leburu and nicole were both very helpful my boss send me to get few items as I wasn't very familiar with the items Leburu and my boss spoke with each ...

Ordered online. Got my order in less than 24 hrs. I was updated all the time on the progress. I have never seen service like this. Thanks and well don...

Unbelievable!! It is now Saturday evening 23 December - 21:15 - and just finished online assistance from Communica - this is service I am not used to ...

Needed to buy a bluetooth GPS receiver. The staff was friendly, knowledgeable and assisted without any issues. This is a toys tore of note for peopl...

Cynthia at the counter is always very helpful, in fact, all the counter sales ladies are very helpful. Can't say the same for the staff when calling ...

After spending 2 days hunting for a component i found it here. Dealt with someone telefonically. Help was quick, answered all questions, and called me...

One of the cashier services rendered to me was here at communica by the lady named Nicole and her manager dolly they were both willing to go above and...

Received exceptional service. They were quick to answer my website enquiry. Then they went out of their way to make up a special industrial automatio...

Awesome place!! They have everything electronics you would ever require cctv, home automation and DIY.Prices are decent and staff are helpful. They ha...

This is the answer to all your electronics equipment needs, they have all the components you require for your school project. The shop is very big and...

Received excellent service as always from Communica, placed an order yesterday for a new Multimeter and was delivered today at 10am, goods were sent f...

Thank you very much Oom Jan for helping me with my school project. I received excellent marks and comments. I highly recommend for other schools to mo...

Fast delivery, reliable and communication 100%. To everyone who like original things I recommend 100% to buy from Communica .keep up the good work Co...

Very friendly, very helpfull even to people like me, who is an hobbiest and does not always knows the right terms. I have been playing with electronic...

I love this shop, it is an electronics dream! The service is typically poor though, and they have a confusing ticketing machine to get attention. Howe...

A world of electronics under one roof!! Vast range of products with knowledgable staff adding to the shopping experience and at competitive prices!! D...

Great place to purchase electronic components at a fair price. They have a wide range of products and a well functioning ticketing system that ensures...

After being supplied the incorrect track for my garage motor, despite me asking twice if it was the correct track, I had to return to the store to exc...

They have most every electronics component you might need. Staff are knowledgeable and friendly. I was looking for a bespoke miniature item for a lapt...

Great inventory. Very slow service, though the staff seem to do their best. Single till open mostly with overbearing security measures. Can do with so...

I visit Communica once in a blue moon. Always wish i have more time to look at everything. Good & friendly service. Nothing wrong with a queuing syste...

The new ticketing system is great, but the queues are still exceedingly long, and there are hardly any staff on hand in the shop to assist with questi...

I needed a heat-sensitive diode as one of my Philips appliances had had a failure. Philips wants you to throw the entire thing away, but I tried look...

Excellent range of items, with technical staff that know their stuff. Unfortunate location that makes it a bit difficult to get to, but worth the tre...

Wide range of electronic components. Very likely to find what you are looking for. Arthur was very helpful. Don't bother trying to call for informatio...

Electronic supply store if you like tinkering it's got the goods the tills are slow so don't expect a in and out visit especially if there is two or m...

Sonoff SV WiFi AC/DC Switch: Installation Guide for Beginners

Safe low-voltage switching

Practical wiring guide

Local procurement tips

Communica South Africa

Overview: What the Sonoff SV is and where to use it

Typical applications

Key specifications at a glance

What you need before you start

Safety and South Africa-specific considerations

Precautions

Basic wiring and configuration

ASCII wiring diagram: 12V LED strip example

Configuration tips

Selection criteria: choosing the right Sonoff SV setup

Spec comparison table

Basic calculations and checks

Troubleshooting checklist

Practical South African examples

Next steps and resources

Sources

DEC cc

Why Choose Communica?

*Free Shipping

7-Day Returns

Quick Delivery

Ian Mugede

Gerrard Cottrell

Erich Dixon

Quint Kloppers

DA Photography SA

Johan Grobler

Tobie Buckle

Raymond Phiri

Herman Beukes

Regardt Smit

Bonolo PowerMan

Kalvin Swart

Alfred Wolpe

John Airth

Walt du Toit

Gundo Ndou

Daniel Kloppers

Koos Liebenberg

THATO M

Deon Joubert

Jacques Westhuizen

Henriqui Dos Santos

Tokky Ademoyero

Julio Mondlate

Leon Ecroignard

Lennin Naidoo

Antoinette Myburgh

Paul Chien

Al

Trevor Sinyoro

Evan Jack

Hlompho Matobole

Jacob Mogano

Kevin

Omphulusa Nkwana

Ampsure Electrical (Ampsure Electrical)

Stephanie Yomi

AY Maleek

Phathwa Senene

Christian Motau

Marius van Niekerk

Tobie Wiese

Martin van Staden

Brenda Matete Maloma

Nolte Smit

Phillip Nthabalala

Simon Khasu

Dieter Claassen

Jax Panix

walter mangando

Chris Courtney-Stones

Mbuelo May

Carl De Beer

Willem Burger