In short: An indoor electrical installation design is prepared with calculations and drawings under the Regulation on Indoor Electrical Installation Design (Elektrik İç Tesisleri Proje Hazırlama Yönetmeliği). For a new building, the design goes to the municipality with the building permit file. Gediz EDAŞ requires an approved indoor electrical installation design for construction power and for the permanent connection. Information is current as of November 9, 2026.
What rules does an indoor installation design follow?
Two regulations. The Regulation on Indoor Electrical Installations (Elektrik İç Tesisleri Yönetmeliği) sets how the installation is built. The Regulation on Indoor Electrical Installation Design lists what the design must contain.
The design is prepared to match the architectural design. It is developed in stages; the final design is the one that goes for approval.
What calculations does the design include?
Calculations that show the installation will operate safely. The regulation requires at least the following:
- Power demand: installed power and demand load
- Cross-section: current-carrying capacity of conductors and cables
- Voltage drop
- Short circuit and selection of protective devices
- Selectivity: in a fault, only the protective device nearest the fault trips
- Grounding: ground resistance and protective conductor cross-sections
- Power factor correction, if needed
Each calculation has a counterpart on site. The voltage drop calculation keeps the voltage adequate at the farthest outlet and motor. The short-circuit calculation shows that the protective device trips fast enough in a fault. The grounding calculation lets current leaking to an enclosure find a path without harming anyone.
What drawings are prepared?
Drawings that show what the calculations mean on site. The main sheets are:
| Drawing | What it shows |
|---|---|
| Single-line diagram | Lines, cross-sections and protective devices from the supply to the last panel |
| Floor plans | Locations of outlets, lighting, branch circuits and panels |
| Riser diagram | Lines from the meters to apartment and common-area panels |
| Panel diagrams | Circuits and load schedule of each panel |
| Grounding plan | Foundation grounding and equipotential bonding |
| Meter panel detail | Meter layout and building service entrance |
In buildings that need an electrical room and a cable shaft, these are shown in the design too. A lighting calculation is optional for residences and required for other buildings.
Symbols come from the symbol list in the Regulation on Indoor Electrical Installations or from the EN 60617 standard. That way every engineer reads the design the same way.
What path does the design take for a new building?
It goes through two approvals: the municipality and Gediz EDAŞ. The design goes into the building permit file; Gediz EDAŞ also approves it separately. Both are obtained before installation work starts.
If the municipality finds something missing or wrong, it returns the design with its reasons. We correct it and resubmit.
Site survey
We review the architectural design, the loads and the connection point. The CAD file of the architectural design speeds up the work.
MCDCalculations and drawings
We do the calculations and draw the sheets to match the architectural design.
MCDPermit annex
The municipality reviews the design and approves it as an annex to the building permit.
Designer → MunicipalityGediz approval (YBS)
As designer of record, we upload the final design to Gediz Elektrik’s online portal (New Connection System, YBS). If anything is missing, we correct it and upload it again. Installation work does not start before approval.
MCD → Gediz EDAŞConstruction power
A temporary connection requires the approved indoor installation design, the title deed and the building permit.
MCD → Gediz EDAŞOccupancy permit
A building without an occupancy permit cannot receive electricity service.
MunicipalityPermanent connection
The connection is made with the approved design, the title deed and the occupancy permit.
MCD → Gediz EDAŞ
If the design changed during construction, an as-built design is submitted before acceptance.
What changes with a capacity increase?
The installation is recalculated for the new capacity. The Regulation on Indoor Electrical Installation Design also applies to modified or expanded parts of existing installations.
If installed power or floor area changes by more than 20 percent, a modification design is required; smaller changes are also added to the design and approved by Gediz.
Voltage drop and short-circuit calculations are repeated with the new load; the main feeder and main protection are reviewed accordingly. The application goes to Gediz EDAŞ; the required documents depend on the type of use.
First we check the condition of the existing installation. In older buildings the main feeder cable may not carry the new capacity; then it is replaced. Rooftop solar PV also requires an electrical design. To get started, send us your latest bill.
Frequently asked questions
Who can prepare an electrical design?
An electrical, electrical and electronics, electronics, or electronics and communications engineer. Electrical technicians may prepare one within their authority.
Does the design need EMO (Chamber of Electrical Engineers) endorsement?
Building permit designs cannot be made subject to professional chamber endorsement. However, the designer of record must be registered with the chamber, and their office must be registered too.
How long is an approved design valid?
If installation does not start within 3 years of approval, the design becomes void. If it starts but is not completed within 5 years, it also becomes void.
Can you get construction power without a design?
No. Gediz EDAŞ requires the approved indoor installation design, the title deed and the building permit for a temporary connection.
Does the Electrical Facilities Project Regulation cover indoor installations?
No. This regulation excludes indoor installations. An indoor installation design is prepared under the Regulation on Indoor Electrical Installation Design.
Sources
- Regulation on Indoor Electrical Installation Design (Elektrik İç Tesisleri Proje Hazırlama Yönetmeliği), Official Gazette No. 25305, December 3, 2003, Articles 8 and 13
- Regulation on Indoor Electrical Installations (Elektrik İç Tesisleri Yönetmeliği), Official Gazette No. 18565, November 4, 1984, Articles 11 and 13
- Electrical Facilities Project Regulation (Elektrik Tesisleri Proje Yönetmeliği), Official Gazette No. 29221 (repeated issue), December 30, 2014
- Planned Areas Zoning Regulation (Planlı Alanlar İmar Yönetmeliği), Official Gazette No. 30113, July 3, 2017, Articles 57 and 64
- Regulation on the Authority, Duties and Responsibilities of Electrical Technicians (Elektrik ile İlgili Fen Adamlarının Yetki, Görev ve Sorumlulukları Hakkında Yönetmelik), Official Gazette No. 33143, January 20, 2026
- Gediz EDAŞ, New Connection
- Gediz EDAŞ, New Connection System (YBS) announcement, May 7, 2025
- Gediz EDAŞ, YBS version transition announcement, September 2, 2026
