View source for Creep Current Resistance

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<span style="font-size:1.2em;font-weight:bold;">Creep current resistance</span>
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==Definition==

Creep current resistance characterises the resistance of a [[Plastics|plastic]] [[Material & Werkstoff|material]] to creep currents that form on the [[Surface|surface]] of this plastic.

In addition to the chemical and physical structure, the creep current resistance of a plastic depends on the level of voltage applied, the type of electrodes and the contamination of the surface.

==Experimental methods==

In practice, the drop test method has become established for determining creep current resistance. The experimental technique and procedure are specified in the DIN IEC 60587 and DIN EN 60112 standards. The experiment is based on a special electrode arrangement. Two bevelled platinum electrodes (5 mm wide, 2 mm thick) face each other at an opening angle of 30° on the plastic surface. Approximately 40 mm above the plastic surface is a dropper, from which a drop with a volume of 20–23 mm<sup>3</sup> falls onto the test specimen every 30 seconds ('''Figure''').

[[File:Kriechstromfestigkeit.jpg|500px]]
{| 
|- valign="top"
|width="50px"|'''Figure''': 
|width="600px" |Creep current tester for determining the creep current resistance of solid electrical insulating materials in accordance with DIN EN 60112
|}

The functional design of modern device systems allows for extremely accurate measurements thanks to fine adjustment options for test voltage, test current, switch-off time, drop size, and drop count.

==Material parameters==

The comparative tracking index (CTI) and the proof tracking index (PTI) are used as [[Material Parameter|parameters]] to characterise creep current resistance.

The comparative tracking index (CTI) is the numerical value of the highest test voltage in volts that a material can withstand under specified conditions without [[Tracking|tracking]] (creep path formation).

The proof tracking index (PTI) represents a specified numerical value of the test voltage in volts that a material can withstand under specified conditions without tracking formation.

==See also==

* [[Electrical Strength|Electrical strength]]
* [[Electrical Conductivity|Electrical conductivity]]
* [[Insulation Resistance|Insulation resistance]]
* [[Tracking]]


'''References'''

* [[Grellmann, Wolfgang|Grellmann, W.]], [[Seidler, Sabine|Seidler, S.]] (Eds.): Polymer Testing. Carl Hanser, Munich (2022) 3rd Edition (ISBN 978-1-56990-806-8; E-Book: ISBN 978-1-56990-807-5; ePub ISBN: 978-1-56690-808-2; see [[AMK-Büchersammlung|AMK-Library]] under A 22)
* Hellerich, W., Harsch, G., Haenle, S.: Werkstoffführer Kunststoffe: Eigenschaften, Prüfungen, Kennwerte. Carl Hanser, Munich Vienna (2004) (ISBN 978-3-446-17617-1; see [[AMK-Büchersammlung|AMK-Library]] under G 1)
* DIN EN 60112 (2024-11); VDE 0303-11: 2024-11: Method for the Determination of the Proof and the Comparative Tracking Indices of Solid Insulating Materials (IEC 112/643/CDV:2024) (Draft) 
* DIN EN IEC 60587 (2022-12); VDE 0303-10: 2022-12: Electrical Insulating Materials Used Under Severe Ambient Conditions – Test Methods for Evaluating Resistance to Tracking and Erosion (IEC 60587:2022)

[[Category:Electrical and Dielectrical Testing]]