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		Protective Measures against Hazardous Contact Voltage - Course: Basic skills and knowledge of electrical engineering. Instruction examples for practical vocational training (Institut für Berufliche Entwicklung, 15 p.)
			(introduction...)
			Introduction
			Instruction Example 4.1. Preparation of a Potential Equalitation
			Instruction Example 4.2. Testing of the Protective Measure of ''Protective Insulation''
			Instruction Example 4.3. Testing of the Protective Measure of ''Protective Conductor System''

Instruction Example 4.2. Testing of the Protective Measure of ''Protective Insulation''

Measuring and testing tools

Protective insulation testing instrument, insulation resistance measuring instrument

Auxiliary means

Measuring lines, test prods

Required basic knowledge

Criteria of the protective insulation, handling of measuring and testing tools, knowledge of measuring and testing processes, how to act after accidents caused by electric current

Sequence of operations

Comments

1. Visual inspection

- Determination of the form of the protective insulation

- No visible damage of the insulation

- No protective conductor connections

2. Measuring

- Testing of the protective insulation

Attention "high voltage" - observe safety instructions!

The protective insulation must stand an alternating current test voltage of 4 kV for at least one minute. (After testing, no damage must be visible at the insulation, such as rupture, arcing or deformation.) With high voltage testing at electronically controlled machines, electronics have to be disconnected or bridged.

- Testing the insulation resistance

The insulation resistance must be at least 1.5 megaohm with a measuring voltage of 100 V!

Testing of the protective measure of "protective insulation"

Sequence of operations		Comments
1. Visual inspection
	- Determination of the form of the protective insulation
	- No visible damage of the insulation
	- No protective conductor connections
2. Measuring
	- Testing of the protective insulation	Attention "high voltage" - observe safety instructions!
		The protective insulation must stand an alternating current test voltage of 4 kV for at least one minute. (After testing, no damage must be visible at the insulation, such as rupture, arcing or deformation.) With high voltage testing at electronically controlled machines, electronics have to be disconnected or bridged.
	- Testing the insulation resistance	The insulation resistance must be at least 1.5 megaohm with a measuring voltage of 100 V!