Grounding/Bonding Test?

Thread Starter


Joined Jul 29, 2013
So Im reading over the notes of an electrician who is no longer at my place of business and he makes mention that all of our automation equipment needs a periodic Grounding/Bonding test.

Now Im not exactly sure on how to go about this, and there's not really a person at my job who I can ask about this.

I dont want to sound dumb; Ive looked online for answers without much luck; but is it simply measuring Resistance or Voltage btwn grounding points and doing a spot check to make sure everything is welded,bolted, joined together?

any help would be appreciated


Joined Apr 24, 2011
What exactly is being measured? What points, to what limits?

At my current job we do a lot of bonding measurements, though we do it manually with a very sensitive ohmmeter using 4-point probes to measure down to tenths of milli ohms (.0001 ohms). As an alternative a power supply, voltmeter and an ammeter can also be used to make low resistance measurements.


Joined Oct 18, 2011
In the AF we tested our central ground every 6 months using a earth ground resistance tester. We also took apart all mechanical connections to our radar systems and cleaned the ground connections and greased them. We just did visual inspections on welded connections.


Joined Oct 18, 2011
This may be a little off topic. When I purchased our house in New Hampshire I inspected the house ground from the power panel to the ground rod. I found a very loose connection on the rod and a very short 3/8" diameter ground rod. The rod was 3 feet long. I replaced the rod. I also found that a good deal of the outlets where the ground was snipped off in the rear of the box. I fixed what I could.


Joined Aug 1, 2013
We use a ground bond tester (that's a real name) . It is a combo current source and milliohmeter. It pumps out a defined current, measures the voltage drop, and tests it against an adjustment setpoint. The test current and voltage test point vary based on some rule set. For example, if the normal AC current is expected to be 10 A, we test at 25 A. or something like that.



Joined Oct 2, 2009
What's the difference between grounding and bonding?

You first bond for marriage and then seek grounds for divorce.

credit goes to cmartinez.