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Seyad Ibrahim
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Join Date: Oct 2012
Posts: 2

Instrument Cable Meggering

10/16/2012 9:57 AM

gents, can u tell me the formula for insulation test? That how much mega ohms will get when we giv 500v.. ?
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PWSlack
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#1

Re: instrument cable meggering

10/16/2012 10:01 AM

Most Clients in industry don't ask for instrument cables to be tested at 500V as this far exceeds any voltage they might see in use. A continuity test is usually all that is required.

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Yahlasit
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#2

Re: Instrument Cable Meggering

10/16/2012 12:09 PM

There is not such a thing as an equivalence between mega ohms and applied voltage.

The resistance measured is a result of dielectric specs, thickness, air gap, porosity, defects and area of the insulator as well as area and shape of the conductors on the sides.

The IR (insulation resitance) tests apply a voltage high enough (500V is very common) to reveal any leakages due to defects in the insulation materials of electrical equipment.

It is a safety test that is non-destructive, as opposed to Hi-Pot, which deteriorates the insulators with every test.

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