All about ITTO

Yes, it is compulsory for all electrical installations, but the frequency depends on the type of building or electrical installation.

At the beginning of 2022, the Ordinance on Low-Voltage Electrical Installations (OIBT) came into force in Switzerland. As owners are fully responsible for the electrical installations they own, they are obliged to have them inspected periodically, at their own expense.

Your distribution system operator (DSO) will send you a request for inspection by post, giving you 6 months to carry out the periodic inspection of your electrical installation.

Depending on the type of property you own, you'll need to do this at different intervals. Your DSO will specify, in its letter, the periodicity that applies to your property and the deadline to be respected. Consult the periodicity table. 

Once the inspection has been carried out, and if no defects are found, a safety report and a test and measurement protocol are sent to the DSO by an independent inspection company commissioned by you. As the owner, you will need to keep a copy of these documents until the next inspection.

In the event of a fault in your electrical installation, you will need to appoint an approved electrician to carry out the repair work in accordance with the fault report drawn up by the independent inspection company. Once the work has been carried out, the safety report is sent to you and your distribution network operator.

At the beginning of 2002, the Ordinance on Low-Voltage Electrical Installations (OIBT) came into force in Switzerland. As owners are fully responsible for their electrical installations, they are obliged to have them inspected periodically, at their own expense.

The owner of the system, or his representative, is required to carry out any repairs to the system requested during the inspection.

Indirectly, because it is the customer's responsibility to report any defects in the installation to the owner.

The final inspection is carried out by the installer, or subcontracted to an independent inspection body, before the system is handed over to the owner.

Acceptance inspections concern new installations other than residential premises. It is carried out within 6 months of handover of the system to the owner by an independent inspection body (other than the installer who carried out the work).

Special case of photovoltaic installations: since January 1, 2018, an acceptance inspection is mandatory for these installations. It must be carried out within 60 days by an independent body. Find out for yourself, as some service providers offer packages that include both the final inspection and the acceptance inspection.

The periodic inspection is carried out by an independent body or an approved electrical fitter at intervals of 5, 10 or 20 years, depending on the case (refer to the periodic table above).

In the case of a change of ownership, the five-yearly inspection must be initiated by the purchaser of the property, or by agreement through the notary. Although strongly recommended, it is not mandatory if the property's last electrical inspection was carried out less than 5 years ago.

There are several possible scenarios:

• At the end of a construction or renovation project, a final inspection is carried out and formalized in a safety report submitted to the owner.
• The ITTO Ordinance also provides for periodic inspections, every 20 years for dwellings. In fact, 6 months before the inspection is due to take place, the distribution network operator contacts the owner to request the safety report.
• if the owner changes, a periodic inspection must be carried out if the previous inspection was performed more than 5 years ago.

Since the amendment of the ITTO in 2022, the periodic inspection of an electrical installation with elements with neutral connection according to diagram III must be carried out every 5 years (instead of 20 years).

If work is to be carried out on this type of installation, an acceptance test must be carried out by an independent body.

To find an independent inspection body, a list is available at the following link: ESTI.

Be sure to enter your commune or a neighboring commune if there are no results.

The aim of the Low Voltage Installation Standard (NIBT) is to protect people, animals and property against the risks and damage that may arise from the normal use of the installation.

The NIBT or SN 411000 contains rules for the programming, construction and testing of electrical installations supplied with nominal voltages up to 1000V AC or 1500V DC. It is based on the Electrical Installation Act (EIA), the Ordinance on Heavy Current (VVV), the Ordinance on Low-Voltage Electrical Equipment (VLV) and the Ordinance on Low-Voltage Installations (VLV).

The ITLN is issued by Electrosuisse, through the Technical Commission 64 (TC 64), which, with the help of representatives from various branches and associations, maintains, modernizes and expands it. EIT.swiss is a member of TC 64, representing the interests and concerns of the electrical industry.