Re: 24V+ Isolated Ground Leak

Paul Stascavage


Thank you for correcting my statement to John and the education regarding voltage vs current.

I am very confused.

The bulb on the Masse Test Light is NOT illuminating on either the POSITIVE or the NEGATIVE side although it used to on the NEGATIVE side. The illumination started shortly after taking ownership in 2016. I had the electrician in Martinique look into that negative leak and he said is was a very small current and not to worry about it but keep an eye on the zincs - which is what I have done since.

Fast forward the clock to a few months ago, and the Masse stopped illuminating on the NEGATIVE side however, when I looked at the zincs, they were very deteriorated so I decided I should test for a leak with the volt meter.

Yesterday I was seeing a very small leak on the negative side of approximately 0.009 volts but I saw 25+ volts on the positive side and that is what got me all worked up and initiated the post.  When taking my readings yesterday I went directly from the battery bank to the yellow/green on the rudder post.  The testing I did last night and this morning was on the wall (or as you say curtain) behind the Nav Station.  At this location, I show house bank voltage on the POSITIVE side and 0.14 volts on the NEGATIVE side with the navigation instrument breaker in the ON position.  I am seeing 0.07 volts on both the POSITIVE and NEGATIVE side when testing with the navigation breaker in the OFF position.  I’m getting these readings when testing between the POS or NEG terminals and the Yellow/Green Bonding wire on the bus labeled “NAVIGATION” just to the right or aft of the bus labeled “PERMANENT”.

You are saying that house bank voltage on the POSITIVE side is normal?

If this is the case, how do I properly test for leakage as I believe the Masse Test Light may not be functioning currently?

All the best,

Paul Stascavage
SM #466 - s/v Rita Kathryn
Currently Exploring City Island, NY

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