Your DB Board and Solar: What an Installer Changes

What is in your DB board now

Open the cover of a typical South African house's DB board (the hinged door, not the panel behind it) and you will usually find:

• A main switch. It disconnects the whole installation from the incoming supply. Eskom's application form for small-scale embedded generation calls this the "point of control".
• An earth leakage unit. Often a wider device with a test button. It watches the current going out on the live conductor and coming back on the neutral. If some of it is leaking elsewhere, through a fault to earth or through a person, it trips. Units set at 10mA or 30mA are the high-sensitivity types used to protect people, as Sparks Electrical News explains.
• Circuit breakers. One per circuit (lights, plugs, geyser, stove, pool pump). Each protects its wiring against overload and short circuits.
• Possibly a surge arrester. A device that diverts voltage spikes from lightning or the network to earth.
• Neutral and earth bars. The rows of terminals where the circuits' neutral and earth wires are connected. You won't see these without removing the inner panel, and you shouldn't.

Older boards may have fewer of these, or older versions of them. That matters later, when we look at why some boards need upgrading.

What a hybrid inverter changes: essential and non-essential circuits

A hybrid inverter has a grid connection and a backup (or load) output. In a typical home installation, the grid supply feeds the inverter, and the inverter's backup output feeds a group of selected circuits. When the grid is up, power passes through to those circuits while the panels and battery help. When the grid fails, the inverter disconnects from the grid and keeps those circuits running from the battery and panels.

That creates two groups:

Splitting the circuits is what keeps a 5kW inverter from being asked to run a geyser element, a kettle and a stove at once. Which circuits move depends on your inverter, your battery and how your house is wired. Our list of appliances worth backing up is a good place to start that conversation.

Some inverters manage this split in the box as well. Solis's single-phase S6-EH1P low-voltage hybrids, for example, list dual backup ports on the datasheet for controlling important and less important loads. The installer still has to wire each port to the right circuits and protection.

Why the separate essential board?

Circuits in older houses are rarely grouped the way backup needs them. The kitchen plugs might share a breaker with the kettle and the dishwasher, or the lights on one side of the house might be on a circuit with an outdoor socket. Moving the right circuits onto a separate essential board, with its own breakers and earth leakage protection, makes the system easier to understand, test and maintain. It also means the next electrician can see at a glance which circuits the inverter feeds.

Sometimes it means rewiring a circuit or two to separate a heavy load from the lights it shares a breaker with. That is a cost a vague quote can hide.

The neutral-earth question, briefly

This is the part of the design that most often causes trouble later, so it helps to know it exists. On the grid, your supply authority provides the connection between neutral and earth. When a hybrid inverter runs in an outage, it is disconnected from the grid, so its backup output needs its own neutral-earth reference for protection devices to work.

Manufacturers handle this differently, and their manuals say so:

• Deye's manual for its SUN-7.6K and 8K single-phase hybrids says that when the inverter is off-grid, "the N line needs to be connected to the earth", through an external relay on some hardware versions or a built-in one on others.
• Sunsynk's 3.6/5kW single-phase manual (v41, July 2024) has a note headed "Only for South Africa". It recommends a permanent neutral-earth bond on the load output, in an external box "clearly marked 'permanent PE/N bond'", and says the inverter's grid supply should be taken from the mains before the main earth leakage unit to prevent it tripping.

You don't need to judge these arrangements yourself. You do need an installer who follows the manual for your exact model and the wiring code, because getting it wrong shows up as an earth leakage unit that keeps tripping, or worse, protection that doesn't work during an outage.

The new devices you will see

A solar installation adds equipment in and around the DB board. Names vary, but a complete design usually includes:

• DC isolators. Switches that disconnect the panels' DC cabling from the inverter so it can be worked on safely. They usually sit near the inverter, sometimes in a dedicated enclosure.
• A PV combiner or junction box with surge protection. Where the panel strings come together, with fuses where needed and a DC surge protection device. Deye's manual asks for a "PV junction box with surge protection", warning that otherwise lightning on the panels can damage the inverter.
• Battery protection. A DC breaker or fuse between the battery and the inverter. Battery cables carry large currents, so this device matters.
• AC isolators and breakers for the inverter's grid input and backup output. Sunsynk's manual says the final installation must include breakers certified to IEC 60947-1 and IEC 60947-2.
• A bypass switch. Many electricians fit one so the essential circuits can run straight from the grid if the inverter is serviced or replaced. Our changeover switch guide explains how this differs from a generator changeover.
• A current sensor (CT clamp). A small clamp around the incoming supply cable that tells the inverter how much power the house is drawing from the grid, so it can limit or prevent export.
• A dedicated point of isolation for the generator. Eskom's SSEG application form requires a main switch and a separate point of isolation for the embedded generator, both "readily accessible to the user", in line with SANS 10142-1. Municipal distributors set their own requirements, so your installer should confirm which apply.

Surge protection on both sides

Surges from lightning can enter through the grid connection or the DC cabling from the roof. A well-specified design protects both: a surge protection device on the AC side, in the DB board, and one on the DC side, in the PV combiner box. Our guide to hail, lightning and surges explains why earthing and surge protection matter more than the panels' hail rating. If a quote lists only one, ask why.

Labels, signage and the single-line diagram

After a solar installation, your house has more than one source of power. The grid can be off and the essential board still live from the inverter. Anyone who works on the installation later needs to know that before touching anything.

Expect three things:

1. Labelled circuits and devices. Every breaker on both boards named, plus clear labels on the DC isolators, battery isolator, bypass switch and any neutral-earth bond box.
2. Warning signage on the DB board that the installation has an alternative supply, so an electrician or a firefighter knows to isolate the inverter, panels and battery as well as the main switch.
3. A single-line diagram. Eskom's form asks for one showing the point of control, the SSEG point of isolation, the generation connection point and the protection devices, "placed in a suitable location inside the metering kiosk or main distribution position".

Labels cost almost nothing to do properly. A board covered in faded masking tape and biro after a solar installation tells you something about the rest of the work.

Why an old DB board may need upgrading

An installer may recommend replacing or extending your DB board. Reasons usually fall into a few groups:

• No space. New breakers, isolators and earth leakage units need room on the rail. A full board means an extension or a new one.
• Condition. Scorch marks, discoloured or loose devices, brittle wiring or a damaged enclosure are reasons to fix the board before adding to it.
• Missing or outdated protection. Some older boards have no earth leakage unit, or devices that are no longer suitable for the new design.
• Poor circuit grouping. If heavy and light loads share circuits, separating them may need new circuits.

There is also a legal reason. Regulation 7 of the Electrical Installation Regulations, 2009 normally requires a CoC for at least the addition or alteration. But regulation 7(3) covers installations that existed before 23 October 1992 with no change of ownership after 1 March 1994. For those, any addition or alteration means the user must get a CoC for the whole installation. If you have owned an older house for a long time, ask your installer early whether this applies, because faults found elsewhere in the house then have to be fixed too.

An upgrade recommendation is not automatically an upsell. Ask the installer to say in writing what is wrong with the existing board and what the replacement includes.

The law: a registered electrician and a Certificate of Compliance

Connecting an inverter to your DB board is electrical installation work under the Electrical Installation Regulations, 2009, made under the Occupational Health and Safety Act:

• Who may do it. Regulation 6 says no one may do electrical installation work as an electrical contractor unless registered as one, and regulation 5 requires a registered person to exercise general control over the work.
• The CoC. Regulation 7 requires the user or lessor of an installation to have a valid CoC with a test report, and a CoC for at least any addition or alteration made after one was issued.
• The standard. The Department of Employment and Labour's November 2025 notice says a registered contractor may only issue a CoC after the inspections and tests needed to make sure the installation is safe and compliant with SANS 10142-1, the wiring code. It also advises checking the contractor named on a CoC against the Department's database. Its October 2025 statement adds that a contractor issuing a CoC for an unregistered person's work commits a criminal offence.

Grid-connected systems usually need more than the CoC. Eskom's form requires an Embedded Generation Installation (EGI) Compliance Test Report signed by a professionally registered competent person, and an inverter that complies with NRS 097-2-1. In Cape Town, the City's SSEG FAQs (January 2025) say a qualified electrician must issue the CoC, including for the AC rewiring for solar or batteries, and an ECSA-registered professional must sign off the commissioning report. Our electrical CoC guide and SSEG registration guide cover the paperwork in more detail.

What the DB board work adds to a quote

We haven't found dated, published South African prices for DB board work on a solar installation that we could stand behind, so we won't give a number. The cost depends on what your board needs, and it can vary a lot between two houses with the same system.

What you can do is make sure the quote shows it. A complete quote should list:

• the essential board (new board, extension or reorganised existing board) and how many circuits move to it;
• any circuits that must be rewired or split;
• DC isolators, the PV combiner box, fuses and DC surge protection;
• battery protection;
• AC breakers, isolators, earth leakage protection and AC surge protection;
• the bypass switch, if one is included;
• the neutral-earth arrangement for the backup output;
• labelling, signage and the single-line diagram;
• testing, the CoC and any municipal or Eskom submissions.

If two quotes for the same equipment differ widely, the board work is often where the gap is. Our solar quote scorecard helps you compare them line by line.

Questions to ask your installer

1. Which of my circuits will be on the essential side, and will they be on a separate board?
2. Does my existing board need replacing or extending? What is wrong with it?
3. Which earth leakage units will protect the essential and non-essential circuits, and do they match the inverter manufacturer's requirements?
4. How will the neutral-earth connection on the backup output be handled for this inverter?
5. Where will the DC isolators, combiner box and surge protection go?
6. Will there be a bypass switch, and how do I use it?
7. Will every device be labelled, and where will the single-line diagram be kept?
8. Who is the registered electrician, and will I get the CoC and test report at handover?

If you want an installer to answer these for your house, Alumo can assess it and quote a hybrid system. Ask for the board work, testing and CoC to be listed. Request an itemised solar and backup quote →

Frequently asked questions

Do I need a new DB board for solar?

Not always. Many installations keep the existing board and add a separate essential board for the circuits the inverter feeds. A new or extended board is needed when there isn't space, the existing board is in poor condition, or its protection doesn't suit the new design. Ask the installer to explain any upgrade in writing.

What is the difference between essential and non-essential circuits?

Essential circuits are fed from the hybrid inverter's backup output and stay on during load-shedding, within the inverter's and battery's limits. Non-essential circuits stay on the grid only and go off when the grid does. Heavy loads such as the geyser, stove and pool pump usually stay non-essential.

Can I put my geyser on the essential board?

Only if the inverter and battery were sized for it. A geyser element draws kilowatts of power for long periods, which would take up much of a small inverter's output and drain a home battery quickly. Most designs keep it on the grid side.

Who is allowed to change my DB board for solar?

A registered electrical contractor, or work under the general control of a registered person, as the Electrical Installation Regulations require. You should receive a CoC for at least the alteration, with a test report. Grid-connected systems usually need extra sign-off for the supply authority as well.

Is SolarGuide the installer?

No. SolarGuide is an independent referral partner. Alumo supplies, installs, finances and warrants the systems. We help you compare options and get a free quote. All pricing is indicative and subject to a site assessment and credit approval.

Sources and review note

Checked on 21 October 2026. The legal requirements come from the Electrical Installation Regulations, 2009, regulations 5, 6 and 7, with regulation 7 read on Acts Online; the Department of Employment and Labour's statement of 22 October 2025; and its notice of 21 November 2025. The point of control, point of isolation, single-line diagram, EGI test report and NRS 097-2-1 requirements are from Eskom's Application Form for SSEG (version 2025V2). Cape Town sign-off requirements are from the City's SSEG FAQs (revision January 2025). Manufacturer requirements are from the Deye SUN-7.6/8K-SG01LP1-EU user manual, the Sunsynk 3.6/5kW single-phase hybrid user manual v41 (19 July 2024, distributor-hosted copy) and the Solis S6-EH1P(3-8)K-L-PLUS datasheet. Earth leakage sensitivities are from Sparks Electrical News (9 December 2021). We did not publish DB board upgrade prices because we found no dated, primary South African source. This guide explains what an installation involves so you can check a quote. It is not wiring instruction, and it does not replace advice from a registered electrician who has seen your installation.