DGUV Regulations 3 and 4 govern the safe handling of electrical systems and equipment. Essentially, the difference between Regulations 3 and 4 lies in their scope of application. Regulation 3 applies to private-sector companies, and Regulation 4 applies to public institutions, although their content is largely identical.

These regulations require operators to conduct regular and timely inspections of all electrical systems and equipment. The purpose of this is to prevent hazards and accidents in the workplace.

The inspection consists of a visual inspection, an insulation resistance test, and a functional test. Defective devices must be taken out of service immediately. After repairs, the devices must be retested before they can be put back into service.

The inspection must be performed by qualified electrical professionals (EFK, electricians, electrical technicians, electrical engineers).

Exception: Under the constant guidance, supervision, and responsibility of an experienced qualified electrical professional, the inspections may also be performed by persons trained in electrical work (EuP). Courses for training EuP are offered by well-known, state-recognized inspection organizations.

Portable electrical equipment refers to devices that can be moved or easily transported from one location to another while in operation and while connected to the power supply. Stationary electrical equipment, on the other hand, refers to equipment that does not have a carrying device and is so large that it cannot be easily moved. This also includes electrical equipment that is temporarily fixed in place and operated via movable connection cables.

Fixed electrical equipment must be inspected every 4 years.

The inspection intervals specified in DGUV Regulation 4 are guidelines for normal operating and environmental conditions and are intended for general reference only. The actual inspection intervals are determined by the employer as part of a risk assessment, which may conclude that the intervals need to be shortened. Causes include exposure to dirt and dust, moisture and wetness, corrosion, oils, greases, acids, alkalis, harsh operating conditions, mechanical stress, and electrical, chemical, and thermal influences.

DGUV Regulations 3 and 4 apply in full to devices used while working from home as well. A mandatory inspection requirement may also apply to personal devices. This is the case, for example, if work devices are permanently powered through a personal power strip.

A DGUV inspection for power cords includes a visual inspection, a protective conductor test (including a bend test), insulation measurement, and a circuit test (continuity and polarity). It must be performed separately from the main appliance by a qualified electrician to ensure that the cord complies with standards and is safe.

The reason for this is that a “combined measurement” (with the cable connected to the device) is usually not reliable. Therefore, a separate inspection of the low-voltage device cable is strongly recommended.

Example: Computers and monitors with power cords: The cable and the device are considered two separate test items. Both must be tested individually. The cable is tested for continuity, insulation resistance, and protective conductor resistance. The main device must also be measured and subjected to a visual inspection.