sundance-communications.com/forum Forums General General Telephone & Systems Information How to test for good ground

I've been using a basic procedure to test for a good ground for years by taking a buttset and connecting the red lead to the ring side of a pots line and then touching the black lead to a ground and seeing if I can pull dialtone. I did this at a site today and the ground is so noisy that I can't hear if I've pulled dialtone or not. How can I check this with a meter? I have'nt needed to do this in so long that I can't remember what the proper way to do this is.

You can measure from the power ground to your ground and should see about 1/2 ohm or less if the ground is good. Just drawing DT with a buttset in no way tells you if the ground is good or not.

You might want to check for voltage differential both AC and DC before you risk the ohmeter portion of your test meter. Just a good practice, seldom justified, but it only takes once to blow up your $20-$200 meter. And I have seen it! And I have seen the wrong side of the outlet hot. The little slot should be 'hot' and the big slot should be nuetral and real close to zero when measuring voltage difference from the nuetral 'slot' to the ground 'hole'. Like less than 1/2 volt. I guess I should stop beating this drum, but we've had a couple of surprises lately with outlets wired 'upside' down. 1 in old construction, 1 in new construction. The 'new' construction was a 4 X 4 box with 2 duplex outlets, 1 right and 1 wrong. Discovered when UPS was plugged into 'wrong' outlet pair and breakers in UPS and panel both went! Along with an interesting flash at the outlet, that had a newbie lookin' for clean underwear! So, we had an impromptu AC building wiring lesson, that he watched like a hawk! John C.

Michael, you may find this article interesting.
https://www.psihq.com/iread/strpgrnd.htm
MrG

If you delete the first seven paragraphs the rest is fairly accurate.

-Hal

Well after reading the article I think what I'm needing is how to test for transient voltage on ground. I'm using the power ground for the system so I don't need to know the resistance there, although I may need to test resistance from telco's ground and power ground.

What is it exactly that you are connecting to ground? We've probably already discussed most situations.

-Hal

Samsung PBX. Have had a system in for a couple of years with a chronic PRI freezing problem. Telco has changed everything. Samsung has changed everything. I've personally installed at least 50 PRI's on various Samsung systems so I've already gone through the normal troubleshooting. Finally had someone at Samsung ask me to check the system ground so here I am. I'm willing to run a separate ground like we used to in the old days, but I want to be sure its good before I do that. And I want to use a meter so I have hard numbers in hand to show the customer.