Electrical refurbishment in existing buildings
We renew outdated electrical systems in residential and commercial properties – in stages while in use, or in one go when the property is vacant.
When a refurbishment may be due
Many systems in older Rendsburg buildings date from a time when a flat managed with two circuits – today, a cooker, home office and washing machine are all connected to it.
Signs from everyday life
- Fuses trip when switching on larger appliances
- Screw-type fuses or distribution board without RCD protection
- Sockets without earth contact, power strips in continuous use
- Cables with fabric insulation or aluminium conductors
- Switches and sockets come loose from the wall
- Usage is changing: home office, wallbox, new kitchen
Three approaches, depending on the property
Not every old system has to be completely torn out. Often a new distribution board with additional circuits is enough, and sometimes only one area is affected – kitchen, bathroom, outdoor area.
- Renew the distribution board and add protective devices
- Renovate individual areas while the rest stays in operation
- Complete renewal when vacant or during a core renovation
Process
How a refurbishment proceeds
Before any chiselling begins, there is a site survey.
We open the meter cabinet, check whether a protective earth conductor is present, measure the insulation resistance of the cables and record the loop impedance, i.e. the resistance in the fault current circuit. This shows which circuits can remain and which need to be rewired. Only then do we draw up a quote with line items you can follow. We plan the work so that your flat or business is usable again every evening.
- 1
Site visit and measurement
We inspect the distribution board, cable runs and sockets, measure insulation resistance and loop impedance, and note where classic earthing or fabric-insulated cables are still in place. Roughly one to three hours per residential unit.
- 2
Concept and quote
You receive a proposal outlining which circuits will be newly installed, where sockets and switches will be positioned going forward, and whether it makes sense to carry out the work in sections or in one go. Line items are listed individually.
- 3
Coordinating the sections
Together we determine the order in which work will be carried out. For occupied flats, we usually start with the meter cabinet, followed by the bathroom, kitchen and living areas.
- 4
Execution
Cutting channels, running cables, fitting boxes, installing and connecting the distribution board. Dust protection and daily rough cleaning are included, and we cover tiles and floors.
- 5
Measuring, testing, documenting
Every new circuit is measured, and every residual current device is triggered and tested. You receive a test report and a labelled distribution board plan.
- 6
Handover
We go through the system with you, explain the distribution board and shut-off paths, and record any open points in writing, such as painting work on the closed channels.
Two approaches
In sections or in one go
Both approaches lead to the same system; they differ in disruption, build time and cost. If you're staying in the flat, working in sections is usually the better option.
If the flat is vacant or already being renovated anyway, doing it all at once is more cost-effective, because cable routes, dust protection and site visits only need to happen once.
Scroll table sideways
| Criterion | Refurbishment in sections | Refurbishment in one go |
|---|---|---|
| Use of rooms | Flat remains habitable, one room or floor per section | Rooms are unusable for days at a time, power partly switched off |
| Typical duration | several short work phases over weeks or months | continuous build time, usually a few days for one flat |
| Cost profile | higher per socket, because site visits and dust protection occur multiple times | more cost-effective per socket, cable routes are opened only once |
| Interim state | old and new exist side by side, documentation is updated progressively | a clear, final state after acceptance, one test report |
| Suits | occupied flats, rented properties with an ongoing tenancy, limited budget | vacant properties, owner-occupied flats before moving in, core renovations alongside other trades |
| Meter cabinet | renewed first, later sections are simply connected to it | completed together with all circuits |
Cost
What the price depends on
A refurbishment isn't billed by square metre, but by the amount of work involved. The largest share comes from the cable routes: how much wall needs to be opened, what material it's made of, and how far it is to the distribution board.
We state these cost drivers openly, so that when you look at the quote, you can see where savings are possible and where they aren't.
- Number of circuits and sockets: Each additional circuit means its own cable from the distribution board to the room and a space in the meter cabinet.
- Wall material: Sand-lime brick and clay brick can be chased easily, while concrete and reinforced concrete take considerably more time. In timber stud walls, chasing is almost entirely unnecessary.
- Condition of the meter cabinet: Old meter installations with screw-type fuses are generally replaced completely, including the meter panel, distribution panel and residual current devices.
- Existing protective earth conductor: If the third conductor is missing, the circuit cannot be upgraded – it has to be newly run.
- Surface-mounted or concealed: Visible installation in cable duct or conduit is noticeably cheaper, for example in basements, garages and utility rooms.
- Additional runs: Network sockets, roller shutter controls, smoke detectors or a supply line for the wallbox are run along at the same time while the walls are open anyway – adding them later costs more.
- Follow-up work: We close chases properly; please budget separately for wallpapering, painting and tiling.
What you can prepare
Ready for a modern electrical system?
We'll take a look at your existing system and discuss the possible next steps.