The most important thing first
Elektroplanung with BIM creates early clarity: cables, connections and interfaces are defined in the model before work starts on site. This reduces errors, makes costs more reliable, and simplifies later operation. The impact can be seen in a school construction project in Märstetten: because a large portion of the electrical installation was prefabricated in the factory, the on-site installation effort dropped by more than half, and the building was ready for occupancy after seven months.
What we repeatedly notice at Pezag AG in practice: the greatest benefit occurs not on the construction site, but much earlier in the planning. By cleanly defining cables, connections and reserves in the model, pressure in the execution is relieved and detours are avoided. This was crucial in the Schulbau Weitsicht project in Märstetten.
What concrete benefits does Elektroplanung with BIM offer for owners?
For owners, BIM makes Elektroplanung tangible because requirements, route of cables and interfaces become visible early. In Märstetten Pezag AG took on the complete electrical specialty responsibility, from concept to Elektroplanung to execution, including photovoltaic system. The execution was prepared so that much did not have to be solved on site. Every project benefits from this: fewer ambiguities in execution mean fewer additional costs and higher quality. In tight schedules, the advantage becomes even clearer because every saved day on site counts.
The Pezag AG took on complete electrical specialty responsibility including concept, Elektroplanung, execution as well as planning, installation and integration of the photovoltaic system.
What prerequisites must be clarified early?
| Topic | What should be defined early | Why this is important |
|---|---|---|
| Utilization | Rooms, loads and reserves | So Elektroplanung fits the later operation |
| Interfaces | Collaboration with architect and other planners | So the models of the trades fit together |
| Extensions | Photovoltaics, e-mobility and building automation | So later functions don't have to be improvised |
| Level of detail | Responsibilities and delivery dates | So prefabrication and installation mesh cleanly |
BIM does not work as a post hoc correction tool. In Märstetten it was crucial that requirements were defined in advance and collaboration coordinated early. Only then could the electrical installation be pre-fabricated in the factory rather than assembled step by step on site.
How did the project unfold in Märstetten?
- Electrical planning was set up in the BIM model and coordinated with the other participants.
- Cables and connections were defined precisely in the model.
- The electrical installation was installed in the factory into the modules.
- On site only the module connections had to be plugged together.
- The system was integrated including photovoltaics.
The Märstetten example clearly shows the practical difference. The plan was a three-story wooden module building with six classrooms, three group rooms and sanitary facilities, realized with KIFA Systembau AG between January and July 2025. For construction there were only seven months available, so prefabrication was not a luxury but a prerequisite.
Pezag AG
Which mistakes in BIM-based electrical planning are most costly?
What matters in practice
A common mistake is using BIM too late. Then cables, connections and reserves cannot be cleanly integrated into the model, and later changes become expensive. Prefabrication only helps if the model is stable; otherwise adjustments involve double work.
Many think digital planning means more effort up front. In reality, this upfront effort pays off during execution: fewer corrections, fewer on-site alignments, less lost time. If BIM does not deliver the hoped-for benefit, it is rarely the model’s fault but usually the late start. If Elektroplanung is only brought into the model after other trades are already fully planned, one can only react rather than co-create.
Classical planning or BIM-based planning?
| Topic | Classical planning | Planning with BIM |
|---|---|---|
| Overview | Individual 2D plans per trade | A single 3D model of all trades |
| Interfaces to ventilation, sanitation, static | Conflicts often only appear on site | Conflicts are identified and resolved early in the model |
| Changes during the project | Must be updated in multiple plans | Managed centrally in the model |
| After handover | Paper or PDF documentation | Model as basis for service and extensions |
| Suitable for | Simple projects like a single-family home | Projects with multiple trades, tight schedules or prefabrication |
| Costs and material | Quantities estimated from plans | Quantities can be derived directly from the model |
For SMEs, municipalities and investors, what the model achieves is more important than the model itself: fewer surprises on site, more reliable costs and a system that can be easily maintained and expanded later. BIM is a tool for this, not a self-serving purpose.
Frequently asked questions
When is BIM particularly worthwhile in electrical planning?
Is BIM also sensible if a photovoltaic system is planned in addition?
What happens if the model changes during the project?
What role does BIM play after construction?
For owners, the core benefit is clear: Elektroplanung with BIM creates early binding, reduces on-site effort and makes prefabrication feasible at all. In Märstetten this approach helped deliver the school project on time despite a tight deadline.
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Pezag AG, Bischofszell