Electrical Project Approval in Bursa: A Step-by-Step Process

Whether you're building a factory, increasing capacity, or renovating an existing facility, electrical project approval is often the most underestimated step in the construction timeline — until the energization date starts slipping. In Bursa, this approval process can take anywhere from a few weeks to a few months, depending heavily on how well the file is prepared. This guide walks through the process end to end: who's involved, what's required, and how to avoid the delays that catch most facility owners off guard.

Why Is Electrical Project Approval Required?

In Turkey, every electrical installation — high voltage (HV), medium voltage (MV) or low voltage (LV) — must have a design approved by the relevant authority before energization. This approval is the official proof that the facility was designed in compliance with regulation on life safety, fire safety and grid compatibility. A facility that lacks approval, or that deviates from its approved design, will have energization refused by both the utility and the OIZ.

Who's Involved in the Process?

In Bursa, a typical electrical project approval process involves three parties:

• The design author (electrical engineer): the party who prepares and technically signs the project.
• The OIZ administration (if applicable): if the facility sits in an organized industrial zone, the project is first reviewed by the OIZ's technical department.
• The utility company: for MV and HV connections, the utility separately evaluates the project for grid compatibility and sets the connection agreement accordingly.

The Step-by-Step Approval Process

1. Preliminary information and site survey: the facility's load profile, existing infrastructure and connection point are clarified. Wrong assumptions at this stage lead to project revisions later.
2. Single-line diagram and calculations: a single-line diagram is prepared, backed by load-flow, voltage-drop and short-circuit calculations. Short-circuit currents are calculated per IEC 60909-0:2016.
3. Cable sizing and protection coordination: cable cross-sections follow TS HD 60364-5-52, and protection devices are set on a selectivity basis.
4. Lighting and earthing design: the lighting design meets TS EN 12464-1:2021 illuminance requirements, and earthing follows the relevant standards.
5. File submission to the authority: the completed project is formally submitted to the OIZ and/or the utility.
6. Review and revision rounds: the authority reviews the project technically and may request revisions for anything found incomplete or incorrect.
7. Approval and connection agreement: once approved, a connection agreement is signed with the utility for MV/HV connections.
8. Implementation and as-built: field implementation follows the approved project; if mandatory site deviations occur, an as-built update is prepared.

What Documents Are Required?

A typical approval file includes:

• Single-line diagram: the master drawing showing the facility's full power distribution hierarchy.
• Load list: a table of each line's and machine's installed power, operating factor and diversity factor.
• Short-circuit calculation report: prepared per IEC 60909-0:2016, supporting breaker and fuse selection.
• Protection coordination report: an analysis showing the staged tripping sequence on a selectivity basis.
• Cable-sizing calculation table: cross-sections calculated per TS HD 60364-5-52 on current-carrying capacity and voltage-drop criteria.
• Lighting calculation report: calculations meeting TS EN 12464-1:2021 illuminance requirements.
• Earthing design: the earthing network design and expected resistance values.
• Additional forms: connection application forms and technical undertakings requested by the utility for MV/HV connections.

OIZs typically require their own standard file format and drawing template; files that don't conform to that format get rejected at first review even when technically correct. That's why obtaining the relevant OIZ's or utility's current specification before preparing the file is the simplest — and most commonly skipped — step in the process.

Planning Budget and Cost Items Up Front

The cost of the approval process isn't limited to the engineering service fee. OIZ and utility fees, connection agreement charges and — where needed — additional measurement or survey costs are all part of the process. Clarifying these line items at the very start of project preparation avoids budget surprises and makes it easier to decide which calculations to prioritize. In capacity-increase projects especially, correctly identifying which part of the existing infrastructure can be reused prevents unnecessary re-investment.

Digital Submission and Post-Approval Follow-Up

Most OIZs and utilities now require projects submitted digitally (CAD drawing files plus PDF calculation reports). A file that doesn't meet digital-submission standards — layer naming, scale, signature-block placement — can get rejected for administrative reasons even when technically sound. And the process doesn't end at approval: as field implementation proceeds according to the approved project, staying in regular contact with the authority prevents surprises at the provisional-acceptance stage.

How the Process Differs by Facility Type

The approval process varies significantly by connection level:

• LV-connected small/medium facilities: the process is relatively simple; a single-line diagram, load list and lighting calculation are usually enough.
• MV-connected facilities with their own substation: short-circuit calculation, protection coordination and a utility connection agreement are added, expanding both file scope and review time.
• HV-connected large industrial facilities: the most extensive process, typically requiring a separate connection agreement, detailed protection coordination and additional correspondence with the OIZ's higher authorities.

Clarifying which category your facility falls into up front lets you set realistic budget and timeline expectations.

Project Revision for an Existing Facility

When a capacity increase, machine addition, or non-conformity fix is needed, we update the existing facility's project through revision rather than starting from scratch. This significantly reduces both cost and approval time — because most of the existing calculations can be reused, with only the changed parts recalculated.

The SOREAS Difference

The biggest time-waster in electrical project approval usually isn't technical error — it's failing to correctly read the authority's expectations from the start. Because SOREAS has worked for years across Bursa's 17 organized industrial zones and with the utility, we know each authority's specific format and documentation expectations up front — which minimizes revision rounds. The project is also prepared not merely as an approval document but as a field-implementable engineering document that allows for future expansion — an approach that speeds up approval in the short term while also meeting your facility's future capacity-growth needs.

FAQ

How long does electrical project approval typically take? It depends on the project's scope, the authority's workload, and how complete the file is on first submission. A complete, consistent file significantly shortens the process.

Is approval required for facilities outside an OIZ? Yes. For facilities outside an OIZ, the project is submitted directly to the relevant utility; the process follows similar steps but without the OIZ's additional specification layer.

What happens if the site deviates from the approved project? Any mandatory site change must be reflected in the project as an as-built update and reported to the authority if required — otherwise it's recorded as a non-conformity at the provisional-acceptance stage.

Is short-circuit and protection-coordination calculation mandatory for every project? For MV- and HV-connected facilities with their own substation, these calculations are almost always mandatory; most OIZs and utilities require them as a standard part of the provisional-acceptance file.

Can the design author be changed? Yes, but the new author must technically take over the project and complete any required revisions under their own responsibility.

Can construction or installation begin before project approval? Civil works can sometimes proceed in parallel, but electrical installation must begin according to the approved project — unapproved implementation risks rework and will be rejected at provisional acceptance.

How long is an approved project valid for? An approved project remains valid until implemented on site; but if it sits unimplemented for a long time and regulation or grid conditions have changed, an update may be requested.

If I operate on multiple OIZ plots, do I need a separate project for each? Yes, each plot/facility requires its own project and approval process based on its connection point and load profile; however, shared standards and reusable calculation methods across plots of the same business can speed up the process.

Do I need a new approval if I only change the equipment brand, not the design? Usually not, as long as the replacement equipment meets the same technical parameters (rated power, short-circuit rating, protection class) the approved calculations were based on. If the parameters differ, a revision is typically required.

Conclusion: A Well-Prepared File Is Time Saved

Electrical project approval is often on the critical path of the construction timeline — a delayed approval means delayed energization, which means a delayed production start. Most of the process isn't within your control (like the authority's review speed), but the quality of the file is entirely within your control. A complete, consistent file prepared to the specific authority's format expectations eliminates the single biggest delay risk you'll face in the approval process.