📚 Knowledge

Topic overview

⚡ Digital meter: consumption, power, and shutdowns

📄 The difference between Boletín Eléctrico, CI, and CAI

📑 MTD or Proyecto – when do you need either document

✔ When is an OCA inspection required?

🏛 Registration with the Consejería de Industria

📜 Why does Endesa sometimes require a new Boletín Eléctrico?

📄 What is a Boletín Eléctrico – and is it the same as a CI?

Yes. “Boletín” is the colloquial term for the Certificado de Instalación Eléctrica (CIE), also known as the CI. It confirms that an electrical installation complies with current Spanish regulations, and can only be issued by an officially licensed Electricista Autorizado or an Empresa Instaladora Autorizada.

🔤 What’s the difference between Boletín Eléctrico, CI, and CAI?

In the Canary Islands, the documentation of the Consejería de Industria often distinguishes between two documents:

CI – Certificado de Instalación is the standard certificate for a new or substantially modified electrical installation, and corresponds to what’s usually referred to colloquially as a Boletín.

CAI – Certificado de Adaptación de la Instalación is used when there isn’t an entirely new installation, but rather, for example, a capacity increase (Potencia) or an extension of an existing installation is being documented.

I check which document is required in your particular case before submitting the application.

📑 MTD or Proyecto – which document is needed when?

For most residential buildings, a Memoria Técnica de Diseño (MTD) is required in addition to the Boletín Eléctrico — it describes the technical details of the installation. As an Electricista Autorizado, I can prepare this myself.

For larger or more technically complex installations, an MTD is no longer sufficient — in that case, a Proyecto Técnico, prepared by an engineer, is also required. I check in advance whether this is necessary for your project.

✔ When is an OCA inspection required?

For certain installations, the law additionally requires an inspection by an OCA (Organismo de Control Autorizado) — an independent, state-approved inspection body that checks the installation before final registration.

🏛 How does registration with the Consejería de Industria work?

Only when all the required documents are complete, they can be registered at the Consejería de Industria. Depending on the project, these include: the Boletín Eléctrico (CIE), the MTD, if applicable a Proyecto Técnico, and if applicable an OCA report. Only when this registration has taken place, the process is officially completed.

📜 How long is a Boletín Eléctrico valid?

Generally up to 20 years. In certain cases, however, the grid operator may require a new certificate earlier.

⚡ Does a capacity increase always require a new Boletín Eléctrico?

Not always. A new Boletín is only required if at least one of the following conditions applies:

• Significant structural changes: structural changes were made to the fuse box (cuadro eléctrico) or the main cable as part of the capacity increase.
• Limit exceeded: the requested power exceeds what the current Boletín allows (e.g. increasing to 7.4 kW under an old certificate limited to a maximum of 5.75 kW).
• Document expired: the last Boletín is more than 20 years old.
• Phase change: switching from single-phase power (monofásica) to three-phase power (trifásica).

📖 Want more background information?

Many of the topics in this knowledge base are covered in detail in my book “Elektrik in Spanien” — with numerous practical examples, photos, and explanations of the differences between German and Spanish installation regulations. So far this book is only available in German.