Depends on the meter.  Does the meter read 0.0 when the leads are shorted 
together?
Some meters have some random fluctuations in the least significant digit all 
the time.  

From: Josh Baird 
Sent: Thursday, March 31, 2016 3:24 PM
To: [email protected] 
Subject: [AFMUG] Another ground question

I'm working on a new DC enclosure (steel 19" rackmount cabinet).  When using a 
DC volt meter, and putting the 'red' lead on a common ground point (my ground 
bus, a metal rack rail, etc), and the 'black' lead on something metal, I'm 
seeing ~0.1V.

I'm assuming this is bad.  On the bench currently, I have the AC ground 
connected to my PSU.  I have all other devices (switch, surge suppressors, rack 
rails, etc) tied to a common ground that isn't yet connected to earth.  My PSU 
and power distribution is on a metal DIN rail which in turn is mounted to the 
metal rack rails. 

Should I be concerned with this?  As much as I try (or not), I still have 
trouble wrapping my head around ground/ground potential/etc.

Josh

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