Planmeca ProMax 3D Max with ProTouch Technical Manual page 103

Protective earthing
Continuous leakage current
Dielectric strength
Technical manual
Measurement between main ground point and A (Fig.1 , Fig2 , Fig.3)
For equipment with a non detachable power supply cord the impedance
between the protective contact in the mains and any accessible metal part,
which is protectively earthed, shall not exceed 300 mΩ.
Measurements shall be peformed using a measuring device able to deliver a
current of at least 200 mA into 500 mΩ. The open circuit voltage shall not
exeed 24 V.
Measurement from protective earth with MD (Fig.4)
The electrical insulation providing protection against electric shock shall be
of a quality that current flowing through it is limited to the specified values.
The specified limit value of the continuous earth leakage current is in normal
condition (N.C) 0,5 mA tested in stand -by condition and in full operation with
the mains in any position.
The continuous earth leakage current shall be measured from a protective
earth conductor with a measuring device (MD).
The dielectric strength shall be tested between live parts with accessible
metal parts, which are protectively earthed , and the enclosure not
protectively e arthed.
This insulation shall be basic insulation and the test voltage for measuring
shall be 500 V for 1 min, when the equipment's mains is connected off from
the line.
During the measurement main switch of the MAINS PART shall be in
operating position (ON), to include, as far as it is practicable , all insulations
of the MAINS PART during measurement.
During the test, no flashover or breakdown shall occur and the insulation
resistance should be least 2 MΩ.
4 Preventive maintenance
Planmeca ProMax 3D Max 97