Life span of conductor insulation

Are there any studies and/or articles that discuss the typical lifespan of conductor insulation? It would be a huge help for us. I
searched the net but haven't come up with anything decent.
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smith snipped-for-privacy@hotmail.com wrote:

Yep, keep looking! Very temperature dependent, IIRC.
It's gone midnight here now and time for beauty sleep - but, if you still haven't found it come morning, I'll go looking and try to find where I read it before. IIRC, it was on a cable manufacturer's website.
--
Sue






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Thanks Sue, I'll look one more time.
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wrote:

Ummm, what do you consider "typical insulation"? And what is a typical conductor? And what are typical conditions?
Insulation can be paper, cloth, plastics, teflon, etc. ... even air or oil! Conditions can be indoor, arial, direct burial, underwater... and so on.
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Palindrome wrote:

. I believe like many reactions insulation life is half/double for every rise/drop of 10 degrees C/18 degrees F. If the temperature is 20 C higher the life is 1/4.
--
bud--

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On Mar 4, 2:23pm, smith snipped-for-privacy@hotmail.com wrote:

Read the Rosch paper at: http://www.electriciancalculators.com/ampacity/ampacity.htm This is a good start although he only investigated rubber insulations.
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wrote:

Read the Rosch paper at: http://www.electriciancalculators.com/ampacity/ampacity.htm This is a good start although he only investigated rubber insulations. --------------------
Some of the links seem to be broken (you have \ instead of / in the addresses).
Charles Perry P.E.
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Thanks, I went through the paper, but most of it was referring to temperature wise.
Also, I would imagine that insulation matterials have changed since then.
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Anixter cable used to have a lot of that data.
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On Tue, 4 Mar 2008 15:23:15 -0800 (PST), smith snipped-for-privacy@hotmail.com wrote:

While I can't reference any specific studies, the gradual deterioration of insulation with time, environment and temperature is the basis for most maintenance tests of insulation resistance using meggers. Insulation resistance is measured in industrial applications regularly to track the actual progress of deterioration in transformers and rotating machinery.
You are likely to find detailed discussions on the subject in the context of insulation resistance measurement.
Chuck
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However, in general the insulation material becomes brittle over time too, regardless of the current/voltage being applied to the conductors?
I understand there are large variations, such as ambient temperatures, usage, current, etc etc that goes into figuring out life expectancy of insulation...However similar to the old cloth type insulation that we could expect XX years of performance before gradual breakdown, isn't there data for todays insulation regardless of application usage?
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On Wed, 5 Mar 2008 11:12:22 -0800 (PST), smith snipped-for-privacy@hotmail.com wrote:

Well, the decrease in insulation resistance begins immediately. The annual decreases are quite small initially, but measureable.
An actual "failure" of insulation is a fairly subjective event though. At what resistance does the insulation no longer "perform"? You get to define performance. Is it leakage? Arcing?
I think you need to specify the problem more concretely.
Chuck
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    smith snipped-for-privacy@hotmail.com writes:

IEE (not IEEE) published lifetimes of the PVC insulation used in UK Twin and Earth wiring. This ranges from 22 years operating continuously at the max operating temperature of 70C, up to just over 1000 years when operating at 30C, IIRC.
This was on the web, but some the the IEE stuff no longer is. I don't have a link handy.
--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]
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