Wavecom TT040-50 Manual do Utilizador descarregar pdf (Página 7)

Wavecom Instruments Fully Integrated Test n Print Unit User Manual

Technical Information

Class 1 (Earthed Appliance) Construction

(Single basic insulated and protectively earth equipment)

This type of product design provides two safety barriers between all live conductors at dangerous voltages and

the equipment user.

The provision of basic insulation between exposed metal parts and live parts is the first barrier to provide basic

protection against electric shock.

The second safety barrier is by the connection of exposed (accessible) conductive (metal) parts to the protective

earthing conductor (earth wire) in the fixed wiring of the device/Installation.

The protective earthing terminal of the equipment must be marked with the word "earth" or the symbol "E" or the

symbol for Earth Terminal or Protective.

To perform this test a continuous earth loop must be made between the exposed conductive material (metal)

and the TnP appliance tester. This is done by means of connecting the earth lead with the crocodile clip/probe

attached to a GOOD earth point (paint & coatings will not provide effective connections) and the DUT (Device

Under Test) plugged into the TnP appliance testers’ DUT socket. The Maximum allowable limit is less than1.0

(ohm).

Refer Page 8 on how to extend time to get a true earth connection ( Unique Earth Bond Test Feature )

Class 2 (Double Insulated) Construction

(Double insulated equipment)

This method of construction employs two safety barriers comprising two layers of insulation between

dangerous voltages and the user of the equipment.

The first layer of insulation is formed around the live conductor and is termed ‘the Functional Insulation’.

The second layer of insulation is termed ‘the Supplementary Insulation’. In Class II equipment, protection against

electric shock does not rely on basic insulation only, but has additional supplementary insulation such as double

insulation or reinforced insulation provided, there being no reliance on precautions in the fixed wiring of

installation.

Class II equipment is marked with the words "DOUBLE INSULATION" or the symbol

For double insulated under Safety Symbols:

Note 1 – Double Insulation is insulation comprising both basic and supplementary insulation.

Note 2 – Reinforced Insulation is a single insulation system with a degree of protection against electric shock,

which is equivalent to double insulation.

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Wavecom TT040-50 Manual do Utilizador Página 7