UL approval “recognized”
The first, ‘recognised’ or ‘Appliance Wire Material (AWM)’, refers to a system in which the basic suitability of all components of a cable (conductor, insulation, sheath, etc.) is tested individually and a cable may be constructed from this modular system. In this case, the rating of the cable corresponds to the lowest rating of a permissible component used. The underlying standards are UL 758 and CSA 22.2-210.
There is also a second type of approval called ‘listed’:
UL approval “listed”
With this type of approval, the complete structure of the cable required for a specific application is specified, for example ‘tray cable’, ‘machine tool wire’ and many more. Although different variants are usually possible here, there is significantly less freedom in the cable structure than with the ‘recognised’ modular system.
There is usually a separate standard for the various ‘listed’ types, e.g. UL 1277 or CSA 22.2-239 for ‘Tray Cable’ or UL 444 for ‘Communications Cables’. Exactly which ‘listings’ can be used for which application is determined by the respective application standards that the customer must follow (NEC, NFPA, etc.).
Obtaining one of these approvals involves regular quality assurance checks by the authorising authority. SAB is therefore regularly inspected by both UL and CSA.
How do the UL/CSA variants differ?
To a large extent, the institutions recognise each other, so that many of the requirements are identical. However, this does not apply across the board. As a result, there are still approval variants in which UL tests according to Canadian standards, CSA according to US standards or both. This results in labelling such as cUL and cULus or CSAus or cCSAus: The capital letters indicate the testing authority, the prefix and suffix the nationality of the standard to be tested.