Products · Faisalabad, Lahore, Punjab
Changeover Switch for Solar, Generator and WAPDA
Short answer
A changeover switch lets your building take power from one source at a time, for example WAPDA (the grid) or a generator, and physically prevents both from being connected together. Its most important job is safety: it stops a generator or inverter from feeding power back into the grid line, where it could kill a lineman working on a "dead" cable. For solar systems, the right changeover depends on whether you have an on-grid, hybrid or off-grid inverter, and whether a generator is part of the setup.
This guide explains manual and automatic changeovers, how they fit with solar inverters, how to size one (including the popular 63 amp rating), and what it costs.
Buy loose or with a system. We sell manual changeovers and ATS units (Chint, TOMZN, CNC, Mora, Pixel) over the counter, or supply them as part of an installed system.
What a changeover switch does
A changeover switch has two supply inputs and one output to your loads. A good one has three positions:
- I: load connected to source one (for example WAPDA)
- 0: everything disconnected
- II: load connected to source two (for example the generator)
The switch is built so that source one and source two can never be connected at the same time. The "0" position matters: it lets an electrician isolate the building fully.
Why backfeeding is dangerous
If a generator is wired to your house without a proper changeover, its power can travel back through your meter onto the street transformer. The transformer steps the voltage up. A DISCO lineman who has switched off a feeder and believes the line is dead can be electrocuted. Backfeeding can also destroy the generator when grid power returns. Never connect a generator, or any inverter output, to house wiring without a correctly installed changeover.
Manual vs automatic
Manual changeover
Low cost; you switch by hand
ATS
Switches automatically; costs more
Changeover switches and solar inverters
How a changeover fits depends on the inverter type. Our hybrid vs on-grid vs off-grid guide explains the types in more detail.
On-grid inverter
An on-grid inverter connects to your main supply and runs alongside the grid. It has built-in anti-islanding protection, so it stops when the grid fails. You do not put the on-grid inverter on a changeover by itself. The changeover sits between the grid and the generator, and the solar inverter joins on the load side.
That creates a second issue: when the generator runs, the on-grid inverter may try to sync with it and push power into a lightly loaded generator. Factories handle this with a solar-generator controller. See solar and generator hybrid systems.
Hybrid inverter
A hybrid inverter has its own internal transfer switch. It takes grid input, and gives a separate backup (EPS) output that stays live from solar and battery during load-shedding. You usually do not need an external changeover between grid and inverter. You may still want:
- a manual bypass changeover, so that you can feed backup loads directly from the grid if the inverter needs servicing;
- a generator changeover on the inverter's grid input, if a generator is used to charge the battery or supply load during long outages. Check that the inverter accepts generator input.
Off-grid inverter
An off-grid inverter often has a utility (AC) input for charging. A changeover between WAPDA and generator on that input lets either source supply it. The inverter output must never be tied back to the grid.
Manual vs automatic changeover switch
| Manual changeover | Automatic changeover (ATS) | |
|---|---|---|
| How it switches | You turn a handle | A controller detects a source failure and switches |
| Speed | As fast as you can walk to it | Seconds, after a set delay |
| Generator start | Manual | Can send a start signal to a generator with auto-start |
| Cost | Lower | Higher |
| Typical use | Homes, small shops, maintenance bypass | Factories, hospitals, petrol pumps, sites with frequent outages |
An automatic changeover switch (also called an ATS, automatic transfer switch) watches the grid. When it fails, the ATS waits a few seconds, signals the generator to start where the generator supports it, and moves the load once the generator is stable. When the grid returns, it waits again to make sure the supply is steady, then switches back.
ATS settings matter. Too short a delay and the switch chatters during brief dips. Too long and sensitive loads see a long outage. These are set during commissioning.
How to size a changeover switch
Current rating
The switch must carry the full current of the circuit it supplies. Common ratings start at 32 A and 63 A and go much higher for factories. The 63 amp changeover switch is a popular size for homes and small commercial buildings, but whether it suits you depends on your load and the rating of your main breaker.
A quick way to think about it, as round illustrative numbers only: a single-phase home with a 40 A main breaker would normally have a changeover rated at least equal to that main breaker, so 63 A gives some margin. The real figure is set by the electrician from your sanctioned load, cable sizes and main breaker.
Poles
- Single-phase: a 2-pole changeover switches both live and neutral.
- Three-phase: a 4-pole changeover switches all three phases and neutral.
Switching the neutral matters, especially with a generator, because the neutral-earth arrangement differs between sources. Our guide on three-phase vs single-phase inverters explains phase choice.
Protection around the switch
A changeover is a switch, not a protective device. Each source still needs its own breaker. See our guide to MCB, MCCB and RCCB for solar, plus a voltage protector where grid voltage swings, and earthing and surge protection.
Changeover switch price in Pakistan
We use CHINT changeover switches and protection devices in our installations.
| Type | Typical use | Price |
|---|---|---|
| CHINT manual changeover, 2-pole, 63 A | Single-phase homes | WhatsApp for today's rate |
| CHINT manual changeover, 4-pole, 63 A | Three-phase homes and shops | WhatsApp for today's rate |
| CHINT manual changeover, 4-pole, higher rating | Commercial and small industrial | WhatsApp for today's rate |
| CHINT automatic changeover (ATS), 2-pole | Single-phase with generator | WhatsApp for today's rate |
| CHINT automatic changeover (ATS), 4-pole | Three-phase with generator | WhatsApp for today's rate |
| Enclosure and installation | Any | WhatsApp for today's rate |
Safe installation checklist
- Use a rated changeover, not two breakers. Two separate breakers can both be switched on by mistake.
- Match the current rating and poles to the main breaker and the number of phases.
- Switch the neutral where the sources need separate neutral-earth arrangements.
- Keep the inverter output off the grid side. Only the inverter's grid input connects to the utility supply.
- Label each position clearly: WAPDA, OFF, GENERATOR, or BYPASS.
- Test both directions during commissioning, and test that the load goes dead in the 0 position.
- Have it installed by a qualified electrician. Changeover wiring sits on the incoming supply, where mistakes are dangerous.
How Solar Works designs changeovers
Our in-house engineers design changeover and protection as part of the whole system, whether it is a home hybrid system or a factory where solar, grid, battery storage and an existing generator all work together. Our industrial and commercial solar page explains how we approach integrated hybrid systems. We install with our own teams, test every switching path before handover, and provide a 1-year service warranty under the applicable project terms. We do not sell generators, but we integrate customers' existing generators into hybrid designs.
Get today's price or a free site survey
Send us your sanctioned load, connection type and a photo of your main distribution board. We will recommend the right changeover and protection.
- WhatsApp or call: 0336 666 4321
- Email: info@solarworks.pk
- Head office: Main Boulevard, Sargodha Rd, Block F FDA City, Faisalabad
- Lahore branch: 2nd Floor, Jeff Heights, Gulberg, Lahore
- Hours: 9:00 AM to 6:00 PM, daily
- Service area: all of Punjab. See our Faisalabad and Lahore pages, or contact us.
Frequently asked questions
What is a changeover switch used for?
It selects which source supplies your building, such as WAPDA or a generator, and makes sure the two can never be connected together. That protects line workers, your generator and your appliances.
Do I need a changeover switch with a hybrid inverter?
Usually not between grid and inverter, because a hybrid inverter switches internally. A manual bypass changeover for servicing, and a generator changeover on the inverter input, are often useful.
What is the difference between a manual and an automatic changeover switch?
A manual switch is turned by hand. An automatic changeover (ATS) detects a grid failure, can start a generator that supports auto-start, and switches the load on its own, then switches back when the grid returns.
Is a 63 amp changeover switch enough for a house?
For many homes it is, but it depends on your main breaker and load. The changeover should be rated at least equal to the main breaker it follows. An electrician should confirm it.
Should a changeover switch the neutral?
In most generator setups, yes. A 2-pole switch for single-phase and a 4-pole switch for three-phase switch the neutral along with the live conductors.
Can I connect an on-grid inverter to a generator?
Not without a proper controller. An on-grid inverter can push power into a lightly loaded generator and damage it. Factories use a solar-generator controller for this.
Which changeover brand do you use?
We use CHINT changeover switches and protection devices. The exact model and rating are listed in your quotation.