Cable Test & Inspection

Question

Can someone explain how electrical cables (industrial use) are inspected and tested ok. How do you determine that the values obtained from the tester (ohm-meter?) are within acceptable range. What standard is used in carrying out this activity?

Many thanks.

Answer 1

Inspection can be a visual inspection - are the cables damaged, cut, or damaged by heat. Sometimes this is hard (like if they are buried)

They are tested using a mega. Isolate the cable and measure the resistance along each core of the cable to check its continuity - it needs a low resistance rating. Can do this by connecting 2 cores together at one end and measuring the whole lot in one go and by various other methods. This proves that the conductors are OK.

A final test is the insulation test, put a high voltage on the cable and measure the resistance to earth proves that the insulation is up to scratch.

In the UK for this to count for anything it should be done by a competant person - and that in reality is someone trained to the IEE 17th edition regulations (they were 16th edition last year - 17th edition is new), and acredited by the NICEIC

Values that are acceptable - continuity test should be low, earth loop impedance (measuring the earth conductor to earth) should be low and insulation resistance should be high

Answer 2

plz see dis site

http://www.usace.army.mil/publications/a...

Answer 3

Domestic Electrical Installation Guide: The NICEIC Guide to Domestic Installation Work - Updated to IEE Wiring Regulations 17th Edition BS 7671: 2008 (Niceic)