
OCA low-voltage inspection: what is checked and when it is due
The periodic low-voltage inspection is done by an accredited control body, the OCA. The company that installed the system cannot do it. Here we explain which installations need it, how often it is due, how defects are rated and how to prepare for it.
The essentials
- ITC-BT-05
- REBT
- OCA inspection
An accredited control body, the OCA, and not the company that installed or maintains the installation. If defects are found, an authorised installer corrects them.
Industrial installations that needed a project and exceed 100 kW installed, places of public assembly, class I fire or explosion risk premises, wet locations above 25 kW, swimming pools above 10 kW, operating theatres, outdoor lighting above 5 kW and electric vehicle charging stations that needed a project.
Every 5 years for all those that passed the initial inspection. Every 10 years for the common areas of residential buildings above 100 kW. This is the general rule of the regulation.
They are very serious, serious or minor. With no very serious or serious defects, the certificate is favourable. With a serious defect, or a minor defect from a previous inspection left uncorrected, it is conditional and a deadline is given to correct it. If the deadline passes without correction, or there is a very serious defect, the result is negative and is reported to the authority.
Keep the design, the diagrams and the installation certificates to hand. Before the visit, measure earthing and insulation and look at the boards with thermography. That is what we do in well-run preventive maintenance.
Sources
Plain-language summary of ITC-BT-05 of the REBT (RD 842/2002) as of 22 October 2026. For a specific case, the text of the regulation and the control body's decision prevail.
Low-voltage electrotechnical regulation, RD 842/2002 (BOE) ↗
Standards for this service
The standards named here
- ITC-BT-05
- REBT
The full list, with the registrations and what each standard requires, is in Standards and registrations.
Recent projects
Tap a photo to see the job from the inside: what was asked, how it was done and what was installed.