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Topic Title: oil filled 11kv cct breaker
Topic Summary: electrical testing
Created On: 20 July 2010 08:00 PM
Status: Read Only
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 20 July 2010 08:00 PM
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ads114

Posts: 34
Joined: 10 July 2009

what's everyones thoughts on this one? i was watching one of these breakers having an oil change recently, once finished it was electrically tested ie "meggered" now here is my question, it was a 1000v megger, each phase and insulator/pole is tested to earth ensuring it's clear, on the Megohm setting, it was then tested between phase's to ensure again there wasn't a short phase to phase also on the Megohm setting.
Should the phase to phase test not have been on the ohm setting as opposed to Megohms?
i was always told megs for insulation resistance,ohms for continuity/resistance only reason being meg ohms can jump a gap and give an incorrect reading?
 21 July 2010 10:07 PM
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rh2577

Posts: 162
Joined: 31 March 2006

Originally posted by: ads114

Should the phase to phase test not have been on the ohm setting as opposed to Megohms?


Assuming that the switchgear is isolated from both the load and supply then this is a valid test to ensure separation of the poles.

i was always told megs for insulation resistance,ohms for continuity/resistance


But you're not testing continuity ph-ph in this case, just ensuring that there is not a short between the individual poles i.e. insulation rsistance (the insulation separating the poles).
HTH

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