Grounding procedures for Partner systems

Hi Ben,
That was not correctly done. The lightning protector must go directly to an earth ground. That means the hydro ground, or a copper water pipe. The ground terminal on the system goes directly to the same point, not to the protector unit. Try to make sure there is no potential difference between your ground and the ground at the outlet.
Each extension that leaves the building must have lightning protection installed on each end. Avaya calls this part an IROB, it's in your manual. This is very important for saftey.
-Chris

Panamax AC protecters ground only to the processer ground and pick up the protection ground from the AC ground(outlet). Any CO lines or out of building EXT's need an earth ground on both ends.(panamax protecters)

In case you are not familiar with what "earth ground" is, I'll elaborate. To have a proper ground, go to Home Depot or another supplier and buy a 5 foot copper ground rod. Go outside your home or place of business and pick a spot close to your foundation that is relatively close to your equipment. Hammer the rod into the ground with a sledgehammer, at least 4 feet. Run a solid copper 8 guage wire from the rod to the ground lug on the Control unit/KSU. Attach the wire to the rod with ground hardware that you can buy in the electric section at Home Depot or somewhere. Many municipalities now use nylon or plastic tube for water mains so grounding to a copper cold water pipe may not always give a proper ground. I'm sure others will add to this.

In case you are not familiar with what "earth ground" is, I'll elaborate.

No, let me elaborate because you have no idea. A ground rod should NEVER be used for grounding anything.

The correct way to protect your system is as follows and this follows the NEC.

1) Provide secondary protectors for all CO lines. Ideally these should be located as close as possible to where the TELCO has installed their protectors and demarc inside the building. The TELCO (and CATV) entrance and protectors should be located with the electrical service so that the grounds can be bonded together. Your secondary protectors (as well as the TELCO and CATV) get grounded to the ground wire from the electrical panel that runs to the cold water ground and the ground rod if there is one. This is called a multipoint ground in that everything gets grounded to the same place as well as to the electrical neutral in the panel. Always use at least a #12 wire, not a piece of 4 pair with all conductors twisted together!

Alternately, if it is not possible to locate or ground your secondary protectors to this point locate them with the system control unit and ground them to the receptacle that supplies the system. This is NOT the ground screw on the processor! DITEK makes a nice device for this. It incorporates a ground binding post with a three outlet surge supressor that plugs into the receptacle.

2) All off premises extensions must have protectors at both ends. Again, follow the grounding methods I outlined. AVAYA has IROB protectors for this- a bit pricy. We use the same secondary protectors as the CO lines. Again, DITEK makes some good stuff. We like to use 5 pin type protectors that have fuses (ITW Linx FPP3-235). These are not self resetting so if the installation is prone to getting hit these will have to be replaced when they do. We feel that they offer superior protection and none of our systems have ever been damaged when installed with these in the way I described above. I've seen the 5 pin protectors blown across the basement but the system was untouched.

3) ALWAYS install QUALITY power line surge protection. I also prefer a UPS to eliminate power problems like off-on-off-on sequencing that can wipe out Partner power supplies.

A word about that ground screw on the processor. It is a supplemental ground that (per UL) should also be connected to ground in case the plug is pulled. Be careful here. The instructions state to connect this to a cold water pipe or building steel. You don't want to do that. ALWAYS connect it to the same place the line cord is grounded which is why I recommend the DITEK 3GTP.

We found this out the hard way, too cheap to buy the 3GTP back then. We had a system that we installed on the third floor of an office building. We grounded the CO line protectors and the ground screw on the processor to building steel, an "I" beam up in the ceiling. All was fine for over two years when we were called to find out why the entire system went down. We found that the processor would not power up. We replaced it. Two days later the same problem. This time I happened to grasp the line cord and found that it was warm! In removing the module I also happened to notice a spark when I removed the ground wire from the screw. I got out my volt meter and found that there was around 50 volts between that "I" beam and the plate on the electrical receptacle. Apparently this is intermittent. Back at the shop I opened the first processor module (ACS R2) and found the reason that it was destroyed. The ground screw is connected to the ground prong on the line cord but not directly. From the screw a wire connects to a trace on the board that runs to the back of the board where it picks up the ground from the power connector. All along the way there are other traces and components connected to this ground trace which was burned in half. This put the 50 volts across components on the board that destroyed them.

Moral of the story is make sure that if you connect the ground screw make sure you connect it to the same point as the line cord ground, not somewhere else.

-Hal

How does that give an isolated ground? If one thing gets hit won't everthing? I'm not being confrontational. I want to learn. Telco has a lightning protector on the side of my house that has ground from a rod hammered into the ground.

Thanks for the info everyone. BTW, I do know what constitutes a multipoint gound, earth ground, isolated ground etc. I work mostly on Norstar systems and Meridian PBX systems. I was just curious as to the correct grounding procedure for a Partner system. If this guy came in and grounded his protectors to the KSU and called it a ground, then he doesn't know what he is doing. My customer is due a claim against his company if he claims that his installation constitutes a ground. I am going to retrofit the system with protectors on either end of the outlying buildings, plus relocating the system so that I can pull a gorund from the ac service panel.


Thanks once again to all

Ben

Ben Crawford
BAC3 Communications
New Orleans, LA
225 315-8822

Hi All,
The point is this. A ground needs to be run from the processor to the same point as the hydro ground as hbiss and I have pointed out. There must be NO potential difference between this and the ground at the outlet. Alternate ground points are normally not allowed. A "tech ground" is driven into the same location as the hydro ground, the earth is verified to be moist to provide a good connection. Tech grounds are not used in phone work.
The reason for this is that a lightning strike will generate thousands of volts per yard of potential difference near the strike. It is very easy to destroy life and equipment with those voltages. The IROBS try to limit the potential difference locally to safer limits. Even with this, I have been shocked in the ear twice, once destroyed the phone & card. A copper water pipe is normally continuous to ground, but of course should be checked.
Another thought. Outdoor cable has a heavy covering and a shield with drain wire. You must use this type.
-Chris

Ground's & Ground's, Look at a panamax protector Schematic, no ground from processer to earth.(only to protector ground) But allways on CO & OPX's.

...Telco has a lightning protector on the side of my house that has ground from a rod hammered into the ground.

Just because TELCO does something doesn't mean that they know what they are doing or what they are required to do. The cable companies are even more guilty when it comes to grounding but they are gradually starting to meet the requirements.

The reason why ground rods are ineffective is because they have a high resistance to ground in most instances meaning that considerable voltage can be present on it and consequently the device connected to it to do damage. The only reason ground rods are used with an electric service is for safety if the neutral or cold water ground should become disconnected. They can provide some degree of protection from a HV power cross or lightning in this case but otherwise are not relied on to do anything.

As for isolated or technical grounds, you can drive a ground rod for these if you want BUT it must be tied back to the multipoint ground also. The reason for this is that a direct short from the power hot to the case wouldn't trip the breaker because of the high ground rod resistance.

A similar situation is the grounds from sat dishes and antennas that are usually just connected to a driven ground rod. I will be the first to admit that it's usually impossible to connect (bond)them to the electrical service ground rods as required.

-Hal