A critical loads panel — also called a backup panel — is a small, separate breaker panel that holds only the circuits a backup power source will feed during an outage. When the grid fails, the backup system, whether a home battery or a bidirectional EV, powers that panel and nothing else, so its limited output is spent on essentials like refrigeration and light. A licensed electrician installs it as part of the backup system; the car never plugs into it directly.
Key Takeaways
- A critical loads panel holds only the circuits a backup source will feed.
- Splitting the house keeps heavy loads from tripping the backup system.
- The circuit list is a design decision, made with an electrician at survey stage.
- V2L needs no panel; wired V2H and home battery systems usually have one.
Why Backup Power Does Not Feed the Whole House
A single EV or home battery system has a modest rated output set against a whole house at full stretch. Put every circuit on backup and one heavy load starting up — an electric dryer, an oven, air conditioning — can exceed what the system can supply and trip it, taking the essentials down with it. Splitting the house solves the problem: the circuits that matter move onto the critical loads panel, and the rest simply stay off until the grid returns. It also stretches the stored energy further, because nothing on the panel is optional. How a two-way system hands over when the grid fails is covered in bidirectional charging explained.
What Usually Goes on the Panel
| Usually backed up | Usually left off |
|---|---|
| Refrigerator and freezer | Electric oven and hob |
| A lighting circuit or two | Tumble dryer |
| Internet router and phone charging | Air conditioning |
| Heating controls and boiler electrics | The EV charger itself |
| Sump or well pump, where fitted | Electric shower |
The exact list is yours to choose with the installer. The pattern behind it is simple: what must never go dark goes on, and what can wait a day stays off. Note the one entry people forget — you do not charge the car from the car, so the EV circuit stays on the main panel.
How the Choice Is Made
Start from a power cut, not from the breaker box. List what the house genuinely needs for a day without the grid: cold food, some light, communications, heating controls, any medical basics. Your electrician then totals the running loads of the chosen circuits against the backup system’s rated output, and moves those circuits onto the new panel. Two practical points follow. Choose with a little headroom, because changing the list later means further electrical work. And expect the decision at survey stage, before the backup hardware is ordered — the panel is part of the system design, not an afterthought. All of it is mains work for a licensed electrician, under the same code framework as any home electrical installation; the safety basics are in are home EV chargers safe.
Panel, Whole-Home Backup, or Just V2L?
There are three levels. Vehicle-to-load through the car’s own outlet feeds one or two appliances by extension lead — no panel and no installation, but nothing is automatic. A critical loads panel gives automatic backup for the chosen circuits, and is the common middle path for wired vehicle-to-home and home battery systems. Whole-home backup covers everything, but needs a far larger system to do it safely. Most homes that install two-way charging land on the middle option; whether the car or a stationary battery should supply it is weighed in is bidirectional charging worth it.
The Everyday Half of the System
Backup is only half the story: the same car still needs ordinary daily charging, and EVDANCE’s range is one-way. A wall charger such as the EV-ACT5006T 48A Level 2 wall charger — up to 48 A, hard-wired or on a NEMA 14-50P plug — handles the daily job, while backup, if you add it, is a separate matched system designed around the panel. The residential charging solutions page covers the everyday side.
Frequently Asked Questions
Can I choose which circuits go on the panel?
Yes. The list is agreed with your electrician at design time. The only limit is the backup system’s rated output — the chosen circuits together must stay within what it can supply.
Does a critical loads panel work with V2L?
No. Vehicle-to-load feeds appliances directly from the car’s own outlet, with no fixed wiring at all. A critical loads panel belongs to wired vehicle-to-home and home battery systems.
Can circuits be added to the panel later?
Usually, yes — but it is further electrical work, and the system’s output still caps the total load. That is why the list is worth planning carefully at the start.
Related Reading
- Bidirectional Charging Explained: V2L, V2H and V2G
- Is Bidirectional Charging Worth It?
- Are Home EV Chargers Safe?
- Solar Panels and EV Chargers: How to Charge Your Car With Sunshine
