Guides · Faisalabad, Lahore, Punjab
Backup Loads Panel: Choosing What Runs During Load-Shedding
Short answer
A backup loads panel (also called an essential loads DB) is a separate distribution board fed from your hybrid inverter's backup output. Only the circuits wired to it stay on during load-shedding; everything else stays on the grid side and goes off with WAPDA. Choosing those circuits well is what decides whether your battery lasts the night and whether the inverter trips on overload.
This guide explains how the split works, which loads usually belong on the backup panel, which do not, and what good wiring looks like.
How a hybrid inverter splits your house in two
Most hybrid inverters have two AC connections on the house side:
- Grid port (also called grid, AC input or on-grid port). This connects to the DISCO supply through your main DB. When the grid is on, the inverter uses it to supply load, and in grid-tied designs it can also export surplus solar.
- Backup port (also called EPS, load or AC output port). This feeds the backup loads panel. When the grid fails, the inverter disconnects from the grid and keeps this port live from solar and battery.
So your home ends up with two boards:
| Board | Fed from | What happens in load-shedding |
|---|---|---|
| Main DB (grid loads) | DISCO meter | Goes off with the grid |
| Backup loads panel (essential loads) | Inverter backup port | Stays on from solar and battery |
On many low-voltage hybrids sold in Punjab, all load passes through the inverter's output and there is effectively one board behind it. On many grid-tied hybrids, especially three-phase models, the backup port is smaller than the inverter's full rating, and some models need an extra backup box before the backup port works at all. Our guide to hybrid inverter transfer time explains how quickly each design switches over.
If you have an on-grid inverter with no battery, there is no backup panel at all, because the inverter must shut down when the grid fails. See can a solar inverter work without a battery?
Backup loads panel
Essential
Lights, fans, router, fridge
Heavy
ACs and motors on grid only
Why not put the whole house on backup?
Owners often ask for "everything on backup". There are three reasons that usually does not work:
- The backup port has a current limit. If the combined load on the backup panel exceeds it, the inverter shows overload and may shut the output off. See inverter showing overload or beeping.
- The battery has a fixed number of kWh. Every extra appliance on backup shortens backup time.
- Starting surges. Motors, compressors and pumps draw several times their running current for a moment when they start. Two of them starting together on backup can trip the inverter.
Running a whole house on solar is possible with the right inverter and battery size, but it is a design decision, not a wiring shortcut. Our guide can you run your whole house on solar? covers that case.
Which loads to put on the backup panel
The question to ask for each circuit is: "Do we need this during a two to four hour outage, and can the battery afford it?"
Usually on backup
- Fans and lights in bedrooms and the lounge
- Wi-Fi router, phone chargers and a TV
- Fridge and freezer
- CCTV, gate intercom and alarm system
- A computer or work-from-home setup
- One inverter AC in a bedroom, if the inverter and battery are sized for it
Usually on the grid side
- Additional ACs beyond the one you really need
- Electric geysers and immersion rods
- Irons, kettles, microwave ovens and electric ovens
- Water motor and pressure pump (see the note below)
- Washing machine and dryer
- EV charger
- Workshop tools, welding plant, and garden or outdoor circuits
The awkward ones
Water motor. Many families want the motor on backup because tanks run dry during long outages. A motor has a high starting current. It can go on backup if the inverter can handle the surge and you agree not to run it with an AC at the same time. Some homes put it on a separate selector so it can be moved between grid and backup by hand.
AC. One inverter AC on backup is common in homes with a suitable inverter and battery. Non-inverter ACs draw a high starting current and drain the battery quickly.
Kitchen sockets. A whole kitchen socket circuit on backup invites someone to plug in a kettle or microwave. Better to put only the fridge socket on backup.
Sizing the backup panel: example arithmetic
The battery has to supply everything on the backup panel for the hours you expect to be without grid power. A quick estimate:
Example arithmetic, with round illustrative numbers: suppose the backup panel carries 6 fans at about 80 W, 10 LED lights at about 15 W, a fridge averaging about 150 W, a router and chargers at about 50 W, and one inverter AC averaging about 1,000 W at night. That is roughly 480 + 150 + 150 + 50 + 1,000 = about 1.8 kW. Over a 3-hour outage the panel uses about 5.4 kWh. Remove the AC and the same panel uses about 2.4 kWh over 3 hours. These numbers are for illustration only; real appliances and habits vary.
Our battery sizing guide and batteries for a full night of backup take this further.
Inverter settings that go with the backup panel
The backup panel works together with the inverter's mode settings. In SBU mode the backup loads run from solar and battery first, even when the grid is on; in SUB or utility-first mode they use the grid first and keep the battery in reserve. Our guide to SBU, SUB and utility-first modes explains which suits load-shedding and which suits net billing.
During normal days, you can get more from the same battery by running heavy grid-side loads in solar hours. See solar load management.
Good wiring practice
A backup panel is permanent wiring, and mistakes can be dangerous. A competent installer should:
- Mark every breaker on both boards so the family knows what is on backup.
- Fit correct protection on the backup panel: MCBs sized to each circuit, and residual current protection where the design calls for it. See MCB vs MCCB vs RCCB and our breakers and protection range.
- Keep the backup and grid circuits separate. A backup circuit must never also be connected to the grid board, or the inverter output can feed back into the grid wiring.
- Follow the inverter manual for neutral and earth arrangement on the backup side. Different models handle this differently.
- Add a manual bypass switch so the backup panel can be fed directly from the grid if the inverter is removed for service. Our changeover switch guide explains bypass and generator changeovers.
- Leave spare ways in the backup panel for circuits you may want to move later.
Common mistakes
- All sockets in one room on one circuit. If the bedroom AC and the room sockets share a circuit, you cannot move one without the other. A survey before wiring saves rework.
- Heavy loads moved to backup "temporarily". A geyser moved over for one winter often stays there, and the battery empties by midnight.
- No labels. In an outage, nobody knows which switch to turn off.
- Backup panel added without checking the backup port rating. The panel looks fine until the first hot evening outage, when the inverter trips.
How Solar Works Pakistan plans the backup panel
During the free site survey we list your circuits with you and agree which ones need to stay on. Our in-house engineers then size the inverter, the battery and the backup panel together, rather than adding the panel as an afterthought. Our own teams wire both boards, label them and show the family how the split works at handover. See what happens during a free solar site survey and our solar inverter price page for inverter options.
We design systems from about 6 kW upward for homes, shops and factories. For factories, the same idea applies at larger scale: critical process loads, lighting and IT on backup, with heavy motors on the grid or generator side.
Get today's price or a free site survey
Tell us which rooms and appliances you need during load-shedding, and send a photo of your current DB.
- 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
We serve customers throughout Punjab. See our Faisalabad and Lahore pages, or contact us.
Frequently asked questions
What is a backup loads panel?
It is a separate distribution board fed from the hybrid inverter's backup (EPS or load) output. The circuits on it stay powered from solar and battery during load-shedding, while the rest of the house goes off with the grid.
What is the difference between the grid port and the backup port on a hybrid inverter?
The grid port connects the inverter to the DISCO supply. The backup port feeds your essential loads and stays live when the grid fails, as long as solar or battery energy is available.
Can I put my AC on the backup panel?
Often one inverter AC can go on backup if the inverter and battery are sized for it. More ACs, or a non-inverter AC, usually overload the inverter or empty the battery quickly.
Should the water motor be on backup?
It can be, if the inverter handles its starting surge and it is not run together with other heavy loads. Some homes use a selector switch so the motor can be moved between grid and backup.
Why does my inverter trip when the grid goes off?
Usually because the loads on the backup panel exceed the backup port's rating, or several motors start at once. An installer should check the load list against the inverter's backup rating.
Can I add more circuits to the backup panel later?
Yes, if the inverter and battery have spare capacity. Ask your installer to check the backup port rating and battery size before moving circuits across.