Single line diagram of your home, premises or building in Seville, Spain: as-built drawings

What a single line diagram of a home is and why you need one

The single line diagram (esquema unifilar) is the map of your electrical installation. On a single sheet it shows how power reaches the fuse board and how it is shared out: main switch, RCDs, breakers with their ratings, the size of each cable and the area each circuit feeds. It is the difference between an installation any professional understands in five minutes and one where you have to switch breakers on and off to find out what turns off what.

Many homes and premises in Seville have no diagram at all, or one that no longer resembles reality after several renovations. We draw the single line diagram of the home, premises or building from what is actually installed.

When you need one

• Legalisations and boletines. The technical design report and the project include the installation diagram, under ITC-BT-04. If you are going to legalise or certify an existing installation, it has to be surveyed. See electrical design report and project.
• Opening business premises. The electrical documents that accompany the licence or the responsible declaration usually require the diagram and plans. More in business opening licence.
• Renovations and extensions. Before adding circuits it is worth knowing what is there and how much room is left in the panel.
• Building maintenance. Communities of owners and companies need to know what each panel feeds in order to locate faults and plan improvements. It fits with building maintenance.
• Sale or rental. A documented installation gives confidence and avoids doubts in the negotiation.
• End of works. Builders, architects and developers need the as-built drawings to hand over the final documentation.

What the survey includes

1. Inspection of each panel: main switch, RCDs, breakers, contactors and other devices.
2. Circuit identification: which lights, sockets and appliances each line feeds, checked on site.
3. Technical data: rating of each protective device, sensitivity of the RCDs and cable sizes.
4. Inconsistencies found: breakers oversized for the cable they protect, circuits without an RCD or undocumented sub-panels. We list them separately.
5. Single line diagram drawn with standard symbols.
6. Floor plans, if you need them, showing panels, light points and sockets.
7. Labelling of the panel to match the diagram.

How we work

1. You tell us what you need it for, because a diagram for a boletín is not the same as the as-built drawings of a building.
2. Fixed quote from a few photos of the panels or a quick visit.
3. On-site survey with short, announced power cuts, circuit by circuit.
4. Drawing of the diagram and plans.
5. Delivery as PDF, and on paper if you ask, with the inconsistencies found and their possible solution.

A typical case

Premises in the city centre are changing use and the new licence requires up-to-date electrical documents. The panel has breakers added at every refit and nobody knows what each one protects. We survey the installation, find two circuits without an RCD and a 25 A breaker protecting a 2.5 mm² cable, correct it with a prior quote and deliver the diagram and plans for the technical design report.

If the survey shows the panel is badly deteriorated or has no room for what you need, we propose a fuse board replacement.

Guide prices

Market estimate. A flat with a single panel is at the low end of the range; premises or a building with several panels and floor plans, at the high end. We give you a fixed price before starting. The rest of our services are under certificates and reports.