Thread: Megger "funny"
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Roger Hayter[_2_] Roger Hayter[_2_] is offline
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Default Megger "funny"

newshound wrote:

Got a heating element in a wallpaper stripper which is blowing 30mA RCD.

Testing live to earth on an old (but "electronic" rather than wind-up)
Megger (which seems to provide 320 volts DC) gives ~ 5 MegOhm.

Testing on a DVM gives ~ 200 kOhm, corresponding to a little over 1 mA
leakage current on mains.

So why the trip, especially given the Megger reading? Or is the megger
f**ed?

Whatever, I guess I need a new megger, any views on the £30 Chinese
models from eBay, or should I be looking at a second hand Avo / Robin /
Fluke etc? This is not for "professional" use, it probably only comes
out a couple of times a year.


Can you test the leakage to the casing of the element on its own removed
from the stripper? If it is still 5 megohms then it is defective. The
discrepancy in the readings is surprising but the cause is uncertain.
Can you test both instruments on a one megohm high voltage resistor?



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Roger Hayter