When is a full electrical project required in Spain?

Common ITC-BT-04 thresholds

This is a working summary. The full instruction must be checked because one installation may fall into several categories.

ITC-BT-04 provides an exception for charging installed in existing group g) and h) car parks within residential buildings: no project is required for that charging work if the new installation falls outside group z). The garage classification alone does not trigger a new charging project in this case.

Extensions and material alterations

An extension can require a project when it crosses a threshold, affects one of the specified groups or, in an installation originally designed by project, cumulative extensions exceed 50% of the earlier design power. Material alterations also need classification.

For the next part of the decision, see the guides to Project or MTD and MTD design report.

How to apply the thresholds to a real property

Your electricity contract alone does not determine whether a Spanish electrical project is required. First classify the installation by its use and conditions: industry, public access, wet premises, parking, generation or EV charging, for example. Then apply the design power specified by ITC-BT-04 and check whether more than one category applies.

An industrial workshop with 25 kW of design power exceeds the general industrial threshold of 20 kW. An 8 kW bar also needs a project, because of its public-access classification. These hypothetical examples show why reducing contracted power does not remove a requirement arising from the installation’s use or design.

For an extension, retrieve the earlier project and consider accumulated modifications instead of looking only at the latest circuit. ITC-BT-04 also covers substantial modifications and particular extensions. The new project should establish the work’s boundaries, its connection to the retained installation and the final documents that need updating.

Why contracted power alone cannot answer the question

The thresholds in the table apply to specific installation categories. For example, public-access premises can require a project even if the owner's expected electricity bill is low. Other categories require an assessment of design power and the conditions defining the group; the contracted power on an invoice is not always the deciding figure.

For an extension, record the power before and after, the parts being changed and any change of use. If the premises or equipment has not yet been chosen, the answer may be provisional: a project requirement depends on a defined technical scope, not a marketing description of the business. Checking this early avoids commissioning a technical report that proves insufficient at registration.