No, the Main Circuit Breaker Upstream of the Meter Does Not Need a Padlock Symbol!
A few years ago, problems arose with circuit breaker types that did not meet the requirements for the main circuit breaker upstream of the meter. The problematic breakers had a replaceable front cover, which could lead to confusion about their current rating. One manufacturer subsequently redesigned its breakers, resolved the issues and began marking the new type with a padlock pictogram. It is important to understand that although the padlock pictogram may identify a compliant product, this does not automatically mean that every circuit breaker upstream of a meter must carry one. Users should be careful and focus primarily on the breaker specifications.
Only a circuit breaker meeting all of the following parameters may be used as the main circuit breaker upstream of the meter:
- Type B tripping characteristic. Type C or D is permitted for appliances with a high inrush current only after discussion with and approval by an authorised representative of the distribution system operator (DSO).
- Short-circuit overcurrent release set to between three and five times the rated current (In) within 0.2 s. A short-circuit overcurrent release that operates above five times In within 0.2 s is permitted only after discussion with and approval by an authorised representative.
- Rated short-circuit breaking capacity of at least 10 kA.
- For three-phase circuit breakers, it must not be possible by design to operate the individual phases independently (the link between the breaker poles must not be removable).
- Unambiguous marking of the current rating (for example, a distinctive colour on the operating lever or the manufacturer’s original label showing the parameters) and of the breaker’s tripping characteristic.
Details of the required parameters and specifications are set out in the distribution company’s connection requirements, available on its official website. The distributor ČEZ has also published a separate document, “Notice on non-compliant circuit breaker types”, which addresses this issue.
It is perfectly acceptable to use circuit breakers that do not have a padlock pictogram.
The connection requirements specify which parameters the circuit breaker must meet.
None of the distributors’ requirements state that a circuit breaker must carry a padlock pictogram.
Our range includes compliant circuit breakers that meet all the distributors’ connection requirements.