Do I need to change my wiring?

No. STS fits onto your existing solar/WAPDA changeover setup. An electrician installs the controller once, and your wiring stays as it is.

How do I know a switch actually happened?

This is what sets STS apart. It doesn’t just send a command and assume — it waits for the device’s own sensors to report that the source really changed, and only then tells you it’s done. If the switch didn’t take, you’re told, not left guessing.

What happens if the power or internet goes out?

The device catches up on its own. The moment it’s back, STS reconciles to whatever the schedule says it should be on right now — including a switch it missed while it was down. It doesn’t get stuck.

Can I still switch by hand?

Always. STS respects a manual change and won’t override it until the next scheduled time. You’re always in charge.

What makes the Industrial version different?

The STS Industrial transfer switch enforces one rule in the equipment itself: only one source can ever be live — never both — so no command, schedule, or mistake can bridge solar and the grid together. It’s built for sites where the supply has to be exactly right, every time, and is designed to align with recognised transfer-switch standards (UL 1008, IEC 60947-6-1).

A WattEY platform · Solar ↔ grid switching

STS — the smart transfer switch for solar and the grid

STS moves your building between solar and the WAPDA grid — from your phone, automatically on a daily schedule, and confirmed every timeby the device’s own sensors. It’s the difference between “I think we’re on solar” and “we’re on solar, confirmed — and it moves to the grid at 5 PM by itself.”

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Already set up? Open the STS app →

Why STS is different

It confirms

Other switches fire a command and assume. STS waits for the device to prove the source actually changed — so you always see the real state, not the last thing you tapped.

It’s safe by design

On the industrial unit, “both supplies live at once” isn’t discouraged — it’s made impossible in the equipment. Safety isn’t a setting you can forget to turn on.

It’s hands-off

Schedules run themselves. Outages self-correct. Manual changes are respected. STS works whether or not you’re paying attention.

How STS works

Step 1

Fit the controller

A small smart controller is wired onto your existing solar/WAPDA changeover switch — once, by your electrician. Your wiring doesn’t change.

Step 2

Connect it

The device comes online on its own. The installer gives you a one-time code; paste it into the app and the device is yours.

Step 3

Control it

Open the app, tap to switch solar or WAPDA, see the live source, and set daily switching times.

Step 4

Forget about it

STS runs your schedule every day. If power drops and returns, it catches up to where it should be. You open the app only when you want to.

One app, three shapes of hardware

STS Controller — multi-circuit

Controls up to four separate circuits independently — switch and schedule each load, and cap how many run at once. For homes and shops that want per-circuit control.

STS Transfer Switch

A dedicated solar/WAPDA changeover unit. One control, two sources, with the device’s own sensor confirming which supply is actually live.

STS Industrial — dual-source

Purpose-built for industry: a latching transfer switch with a hard safety interlock (one source at a time, never both), fully schedulable, every switch confirmed by the device’s sensors.

Who it’s for

Homes — free solar by day, grid by night, set once.
Shops & offices — switch branches to the right source from your phone, without a trip.
Industry — where the supply must be exactly right and never both at once.
Installers — register a device, hand over a code, manage a whole portfolio from one dashboard.

Where it fits

STS is the switching layer of the WattEY platform — alongside Solar Performance Cloud for solar inspection and TenantBill for commercial billing. It pairs naturally with a solar installation.

Frequently asked questions

What is STS?: STS (Smart Transfer Switch) is a Wattey Energy product, part of the WattEY platform, that moves a building between solar and the WAPDA grid — from your phone, automatically on a daily schedule, and confirmed every time. A small controller fits onto your existing changeover hardware; your wiring doesn’t change.
Do I need to change my wiring?: No. STS fits onto your existing solar/WAPDA changeover setup. An electrician installs the controller once, and your wiring stays as it is.
How do I know a switch actually happened?: This is what sets STS apart. It doesn’t just send a command and assume — it waits for the device’s own sensors to report that the source really changed, and only then tells you it’s done. If the switch didn’t take, you’re told, not left guessing.
What happens if the power or internet goes out?: The device catches up on its own. The moment it’s back, STS reconciles to whatever the schedule says it should be on right now — including a switch it missed while it was down. It doesn’t get stuck.
Can I still switch by hand?: Always. STS respects a manual change and won’t override it until the next scheduled time. You’re always in charge.
What makes the Industrial version different?: The STS Industrial transfer switch enforces one rule in the equipment itself: only one source can ever be live — never both — so no command, schedule, or mistake can bridge solar and the grid together. It’s built for sites where the supply has to be exactly right, every time, and is designed to align with recognised transfer-switch standards (UL 1008, IEC 60947-6-1).

Take control of your power

Talk to us about fitting STS to your home, shop, or facility.

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