im trying to see if my panel is grounded and bonded ,have added a circuit and didnt see the bonding screw.It has a silver ground going from neutral bar to copper pipe(but is 25 ft away).
Any info is appreciated
If you read more than a few millivolts there is no continuity or there is enormous current flowing (not good) between these two points.
If you get less than 1 or 2 volts you should confirm continuity with a battery operated test light that uses a small incandescent bulb. These testers put at least 1/4A through the circuit being tested.
Bonded equals "low impedance electrical continuity" and also implies that the connection can stand to pass considerable current.
This tests continuity only. Whether it achieves this connection by NEC approved methods is another question.
Search this http://freenec.com/T1.html
with keywords like bonded, bonding, bond, etc. Article 100 (which you should search) has definitions.
It's not the same as grounding. Space station wiring can be bonded.
With a few dollars for a transformer and power resistor you can pass heavy current through this connection and check the connection integrity with your meter.
Hi thanks for the info.I went ahead and bonded the box in both areas(neutral bar screw and jumper) and secured the aluminum to copper pipe connection for grounding(with anti corrosion on it).
.Had to use a diffrerent bonding screw though..(green one-1 1/2 inch was too small)
If you see anything that looks off let me know.