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Lighting Circuit Blowing........
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<blockquote data-quote="SPECIAL LOCATION" data-source="post: 28462" data-attributes="member: 250"><p>The IR test proves the integrity of the cable insulation to contain the electricity it has to pass... It is not proving a short.</p><p></p><p>you could have something that is breaking down to say around 10ohms L-N.. at 230v (but wont show on a low voltage dc resistance test.)</p><p></p><p>Which would be no problem on a socket or cooker or shower circuit!</p><p></p><p>But on a 5A lighting circuit could be letting nearly 5x is rating pass through.. then as the cable gets warmer..</p><p></p><p>lets even more current thorough.. but when it cools back down... show no problem with a low 9v or 12v resistance test...</p><p></p><p>Do a 250v then 500v IR test... find out if you are shorting L-E or L-N??</p><p></p><p>Really this should jut be a mater of checking the basic dead tests.. Continuity, Ins Res &amp; polarity.. and tracing through till you find the offending item?</p><p></p><p>going back to your first post you said you had reading greater then 99.9Kohms.. with resistance..</p><p></p><p>do you mean they were off the scale of your meter?</p><p></p><p>so you don't actually know what readings they were?</p><p></p><p>Or was that the actual value?</p><p></p><p>there is obviously something missing in what you have tested or the reading you have got?</p><p></p><p>An IR test should be greater then 2MegOhm... so anything in the K's is too low anyway!</p><p></p><p>to exceed 5amps you should have a reading 46ohm or lower?</p></blockquote><p></p>
[QUOTE="SPECIAL LOCATION, post: 28462, member: 250"] The IR test proves the integrity of the cable insulation to contain the electricity it has to pass... It is not proving a short. you could have something that is breaking down to say around 10ohms L-N.. at 230v (but wont show on a low voltage dc resistance test.) Which would be no problem on a socket or cooker or shower circuit! But on a 5A lighting circuit could be letting nearly 5x is rating pass through.. then as the cable gets warmer.. lets even more current thorough.. but when it cools back down... show no problem with a low 9v or 12v resistance test... Do a 250v then 500v IR test... find out if you are shorting L-E or L-N?? Really this should jut be a mater of checking the basic dead tests.. Continuity, Ins Res & polarity.. and tracing through till you find the offending item? going back to your first post you said you had reading greater then 99.9Kohms.. with resistance.. do you mean they were off the scale of your meter? so you don't actually know what readings they were? Or was that the actual value? there is obviously something missing in what you have tested or the reading you have got? An IR test should be greater then 2MegOhm... so anything in the K's is too low anyway! to exceed 5amps you should have a reading 46ohm or lower? [/QUOTE]
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