hawkflorida
Technical User
I would like to hear how other Technicians have properly grounded MICS KSUs and Modules.
Thanks
darnold@americaii.com
Thanks
darnold@americaii.com
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Proper Grounding of MICS 1
- Thread starter hawkflorida
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hawkflorida
Technical User
Yeah.... just wanted to verify. darnold@americaii.com
defaultgeek
IS-IT--Management
Yes that's fine unless there is a +/- ground potential or other signaling problem. It can show up in E&M interfaces, especially oversea's. Improper ground can burn out or shorten cards lifespan.
Workaround is a 10' or 20' copper grounding steak hit into the earth and then strap it down, tie to MICS Chassy ground w/ braided 10 AWG. Parts are available Graybar Electric. This process fixed a Passport 4400 in Mexico where seasonal rains effected the integrity of grounding.
Workaround is a 10' or 20' copper grounding steak hit into the earth and then strap it down, tie to MICS Chassy ground w/ braided 10 AWG. Parts are available Graybar Electric. This process fixed a Passport 4400 in Mexico where seasonal rains effected the integrity of grounding.
A good ground shouldn't give you a + - potential. And that again can be fixed with a good power bar and a plug adapter with a seperate gnd connection.
Good grounds are not always easily got and the ground stake is a last resort... but a good one.
PhM
Good grounds are not always easily got and the ground stake is a last resort... but a good one.
PhM
If I have intermitent problems with analog DID and E&M Tie line. I usually have them call electrician and make sure outlet is dedicated and has an isolated ground. We also use a ground for the CO lighting protection and UPS (battery backup) if customer has one.
Good Luck!!
Good Luck!!
defaultgeek
IS-IT--Management
Steak sorry, stake, I was hungry earlier. Yes once we had a shifting Neutral 0 volt that drifted up to +2 to -4 volts due to poor ground, so -48v went to -52 volts and E&M blew. We fixed with stake. Prior to fail one by one each E&M TX failed, it was difficult to troubleshoot because we could still pull a dial tone from the far side. Also prior to fail there were pops and clicks in the voice quality, then low voice then full failure.
I am starting a new thread and would appreciate your input regarding Northstar T1 cards.
I am starting a new thread and would appreciate your input regarding Northstar T1 cards.
Norstarguru
Vendor
Watch your voltage if Norstar falls below 117 it wigs out and the system will start doing funky things, make sure the circuit is dedicated.
john1@refurbphones.com
john1@refurbphones.com
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1
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Ask the electrician if the 3rd wire is a "conduit ground." If so, have 'em pull a green wire back to main service entrance ground, or put in a ground rod and bond it. The surge supressor won't work if the ground is bad, and the "float" can kill you, literally. It's a big problem in old buildings. Another alternative is a power line conditioner, but that's very expensive. Any time I find a "spooky" intermittent problem, the ground is the first place I look. Put a meter from the ground pole in the outlet (the round hole, the metal box or conduit) to any handy metal object - cold water pipe, ceiling grid, roof steel, metal column or whatever and see if you have a float. A fraction of a volt is not unusual, but if you see much more than that, get an electrician and find out why. It will save you a lot of time trying to fix your equipment when it's not the problem. Howard Dingman
Pro-Tel Communications
Endicott, NY 13760
mailto:hdingman@holocom.com
Pro-Tel Communications
Endicott, NY 13760
mailto:hdingman@holocom.com
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hawkflorida
Technical User
Thanks for the instruction Howard. 
If the fraction is let's say 0.9 is that acceptable? Do you have any other techniques of testing. I used to do one on a Mitel PBX but can't remember what it was specifically. I do remember I took two measurements but am not sure. I agree there are probably quite a few spooky problems related to this issue. darnold@americaii.com
If the fraction is let's say 0.9 is that acceptable? Do you have any other techniques of testing. I used to do one on a Mitel PBX but can't remember what it was specifically. I do remember I took two measurements but am not sure. I agree there are probably quite a few spooky problems related to this issue. darnold@americaii.com
Most of the time, it's either less than a volt, or up in the 10-20 volt range. I've had it as high as 80. Bad news.
Another thing to watch for on older buildings is flotaing neutral. It makes the line voltage in the outlet vary depending on building-wide load.
If you suspect that power source is your problem, it's a good idea to get a recording monitor and check it out. Something like the Dranetz 626 or 646 Power Line Disturbance Analyzer. You just load it with paper tape, plug it in, and come back in a day or two. When you first turn it on you get a printout, then each time there's a fluctuation, it prints how high, how low, how long, and more. When things are bad, the printer can hardly keep up. When things are OK, you can leave it for a couple of weeks and not catch anything at all. It's great for the "once-in-a-great-while" intermittents, because you just leave it running in the phone closet until the failure occurs, and then check if there was a power "event" at the time your failure occurred.
One time, we found that the solenoid coils from an old timeclock-bell system were causing power spikes all over the building. When they stopped using the clock, they just took the gongs off the bells, but the solenoids were still actuating throughout the plant. They threw spikes and transients back onto the power lines; made a mess, electrically speaking.
BTW, our local utility will accept a Dranetz printout as proof of a problem, and dispatch a line crew to repair, no-charge. Of course, that's after the customer has already paid an electrician to go through the service entrance and tighten all the connections there. But without the printout, they just say, "sorry, there is no problem with our power supplied in that area." When you then say, "I have a Dranetz tape that says there IS a problem," they ask, "can you send it to us?"
I send them a COPY and keep the original. Learned that one the hard way, too. ;-) Howard Dingman
Pro-Tel Communications
Endicott, NY 13760
mailto:hdingman@holocom.com
Another thing to watch for on older buildings is flotaing neutral. It makes the line voltage in the outlet vary depending on building-wide load.
If you suspect that power source is your problem, it's a good idea to get a recording monitor and check it out. Something like the Dranetz 626 or 646 Power Line Disturbance Analyzer. You just load it with paper tape, plug it in, and come back in a day or two. When you first turn it on you get a printout, then each time there's a fluctuation, it prints how high, how low, how long, and more. When things are bad, the printer can hardly keep up. When things are OK, you can leave it for a couple of weeks and not catch anything at all. It's great for the "once-in-a-great-while" intermittents, because you just leave it running in the phone closet until the failure occurs, and then check if there was a power "event" at the time your failure occurred.
One time, we found that the solenoid coils from an old timeclock-bell system were causing power spikes all over the building. When they stopped using the clock, they just took the gongs off the bells, but the solenoids were still actuating throughout the plant. They threw spikes and transients back onto the power lines; made a mess, electrically speaking.
BTW, our local utility will accept a Dranetz printout as proof of a problem, and dispatch a line crew to repair, no-charge. Of course, that's after the customer has already paid an electrician to go through the service entrance and tighten all the connections there. But without the printout, they just say, "sorry, there is no problem with our power supplied in that area." When you then say, "I have a Dranetz tape that says there IS a problem," they ask, "can you send it to us?"
I send them a COPY and keep the original. Learned that one the hard way, too. ;-) Howard Dingman
Pro-Tel Communications
Endicott, NY 13760
mailto:hdingman@holocom.com
Another BTW - I found a good management-layman explanation about power line disturbances at
It has a broken link at the bottom of page 2, it won't click. Just change the 2 to 3 in the address, and you'll get to page 3. I e'mailed the webmaster to fix it.
Page 3 is important, too. It shows your customer that surge suppressors fix impulse and repetetive noise, but not sag/surge/dropout/float problems. It's a good tool, but not a fix-all. Also note that "Online UPS" IS a fix-all. If you have a rack of lead-acid batteries that keep your system running 24x7, with the charger supplying power and the system running on the batteries always, that's an "online UPS". It's what Telco uses.
On page 5, there's a chart of computer failures that can be caused by power line problems. It shows that "Miscellaneous Soft Errors" can be caused by almost any disturbance. Again, it's a 3rd-party source to substantiate your suggestion that power problems may be partly responsible for the customer's phone outages.
Howard Dingman
Pro-Tel Communications
Endicott, NY 13760
mailto:hdingman@holocom.com
It has a broken link at the bottom of page 2, it won't click. Just change the 2 to 3 in the address, and you'll get to page 3. I e'mailed the webmaster to fix it.
Page 3 is important, too. It shows your customer that surge suppressors fix impulse and repetetive noise, but not sag/surge/dropout/float problems. It's a good tool, but not a fix-all. Also note that "Online UPS" IS a fix-all. If you have a rack of lead-acid batteries that keep your system running 24x7, with the charger supplying power and the system running on the batteries always, that's an "online UPS". It's what Telco uses.
On page 5, there's a chart of computer failures that can be caused by power line problems. It shows that "Miscellaneous Soft Errors" can be caused by almost any disturbance. Again, it's a 3rd-party source to substantiate your suggestion that power problems may be partly responsible for the customer's phone outages.
Howard Dingman
Pro-Tel Communications
Endicott, NY 13760
mailto:hdingman@holocom.com
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