Clas Ohlson UT33D - Information about the meter; Categorisation

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UNI-T UT33D Multimeter
Art.no 36-6247 Model UT33D
Please read theentire instruction manual before using theproduct and then save
it for future reference. We reserve theright for any errors in text or images and any
necessary changes made to technical data. In theevent of technical problems or other
queries, please contact our Customer Services (see address details on theback).
Information about themeter
The multimeter has been designed and tested in accordance with therequirements for
installation category II up to nominal voltages of 250V and acontamination level of2.
Categorisation
Meters are divided into different categories depending on theelectrical environment
in which they are to be used and how safe/protective they are in theevent of
avoltagesurge.
The meter label should indicate which category it belongs to. Thecategorisation also
determines how safe theinstrument is with regards to any overvoltage which could
represent ahazard for theuser.
The categorisation is described briefly below:
In theevent of avoltage surge in theelectricity grid (a transient from alightning strike,
etc.), therisk will be greatest where themains supply cable enters thebuilding, for
example. Further inside thebuilding, theresistance (impedance) in thecables will
increase and connected devices will reduce and dissipate theovervoltage. Themeter
category will therefore determine which electrical environment theinstrument is
designed to be usedin.
The categories which meters are divided into are as follows:
• Category I:For measuring electronics and products that have inbuilt protection
against voltage surges.
• Category II: For measuring single-phase equipment which is fed via thebuilding’s
electrical power supply system. Bothplug-connected and permanently installed.
• Category III: For measuring thebuilding’s electrical systems. Permanently installed
cables, sockets, fuse boxes and switchgear cabinets. Three-phase distribution
(allpower supply cables and three-phase equipment, machinery and appliances).
• Category IV: Three-phase at primary level and all conductors for outdoor use.
This multimeter belongs to installation category II and is intended for measuring
voltages of up to 250V in single-phase products. Themeter must not be used for
measuring three-phase products, three-phase conductors or switchgear cabinets
even if thenominal voltage does not exceed 250V.