The safety standards relating to the building of electrical panels for the North American market require extensive knowledge from Italian manufacturers and designers.
The North American approach is completely different from the European one. Self-certification is not considered enough and the safety of plants or machinery is based on the condition that everything has been previously checked and certified.
Why do we often talk about UL even if there are many other certification entities?
UL (Underwriters Laboratory) is the main laboratory in the USA and one of the best known in the world. This is why it is recognized as a leader in the field of safety tests and its standards are normally applied by other test laboratories. The organization to which Technology BSA relies on for its certification service is called ETL, in order to guarantee the certification service of electrical equipment in the assembly of automation panels (Industrial Control Panel) and on the machine / plant in reference to the Field Evaluetion standard for the United States and SPE 100 for Canada.
UL508A is the reference standard for industrial automation designers and is divided into sections: the first contains rules for all equipment to which are added other sections containing rules for some specific types of machines.
Except for some restrictions, it’s not mandatory to certify the plant or the machine as a whole through a third party at the time of installation. But obtaining the certification of a laboratory is possible only in the presence of a verification procedure and a specific standard. Even if the certification is voluntary, it’s the best way to avoid disputes with local authorities and insurance companies.
Technology BSA organizes with Rockwell Automation a free course on UL/CSA regulations that will allow you to deepen the topic with qualified technicians on the certification required by the USA and Canada: February 12, 2020 at the Ca ‘Rapulin (AT – Italy) conference room.
FOCUS ON….DIFFERENT TYPES OF CIRCUIT
The UL508-A standard, unlike the European one, divides the power circuits into two parts, for the choice, sizing and wiring of the components inside the electrical equipment:
- Feeder Circuit: all circuits and conductors upstream of the final overcurrent device protecting of a branch circuit
- Branch Circuit: the conductors and components downstream of the final overcurrent device protecting the circuit and the outlets(Branch Circuit Protection)
Example: The branch circuit starts at the fuse connection terminals. While the transformer and its protection at the primary must be considered part of the feeder, therefore in cases with transformers and / or autotransformers the Branch circuit always starts at the secondary of the transformers / autotransformers.
