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Rotary Switch Utilisation Categories

vantech

Hi, 

I am looking for a rotary switch which can act as an isolator for an entire installation. 

There are different types of utilisation categories, which outline certain load types for operation and switching (AC1, AC2, etc.) 

Obviously a standard installation has any number of load types connected to it that are not covered by the specified utilisation categories. 

How is the generally covered? The isolator will be ON 24/7, therefore no mechanical switching will be taking place. I believe that generally the utilisation categories relate mainly to the switching on/off of the load, rather than the load itself during operation. 

Thanks. 

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  • 0

    It's a little more tricky than just switching on/off, as the actual category is defined in the relevant part of BS EN 60947 (or alternatively, BS 61095).

    A (very long, approx 3 page) list of examples is provided in Guidance Note 2 Isolation and Switching (Table 3.2, page 39, in the 8th Edition, or page 41 in the 9th Edition)

  • 0 in reply to gkenyon

    Thanks. 

    This is a bit of a minefield as without access to these product standards, it’s very difficult to fully understand the intent. 

    The categories remain the same in any instance. The switch (and indeed something like a contactor) data sheets all indicate specific utilisation categories. I have seen standard installation contactors used on installs with attention only paid to the loading, rather than a specific category; these generally last for years (the coil is what usually fails). 

    There must be a general rule that’s applied?

    This 100A main switch had a UC of AC23: 

    https://pdg.cef.co.uk/downloads/pdg/eaton_ems1001n_datasheet/eaton_ems1001n_datasheet.pdf

    It makes no reference to resistive or capacitive load types, which would likely be connected as well as inductive loads, which is what AC23 relates to “Switching of motor loads or other highly inductive loads”. 

Reply
  • 0 in reply to gkenyon

    Thanks. 

    This is a bit of a minefield as without access to these product standards, it’s very difficult to fully understand the intent. 

    The categories remain the same in any instance. The switch (and indeed something like a contactor) data sheets all indicate specific utilisation categories. I have seen standard installation contactors used on installs with attention only paid to the loading, rather than a specific category; these generally last for years (the coil is what usually fails). 

    There must be a general rule that’s applied?

    This 100A main switch had a UC of AC23: 

    https://pdg.cef.co.uk/downloads/pdg/eaton_ems1001n_datasheet/eaton_ems1001n_datasheet.pdf

    It makes no reference to resistive or capacitive load types, which would likely be connected as well as inductive loads, which is what AC23 relates to “Switching of motor loads or other highly inductive loads”. 

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