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Metro1000 introduces the Universal Grounding Code.
The generic grounding specifications are shown in Table 1.
| No. | Description |
|---|---|
| 1 | Grounding design should be designed according to the principle of equalizing voltage and equipotential, that is, work grounding, protective grounding (including shielding grounding and distribution frame lightning protection grounding) together with a group of grounding body joint grounding method. |
| 2 | Cabling racks, hanging iron racks, cabinets or enclosures, metal ventilation ducts, metal doors and windows in the computer room should be used for protective grounding. |
| 3 | Normal non-electrified metal parts of the equipment should be made protective grounding. |
| 4 | Ensure that the grounding wire has good contact with the protective grounding row in the machine room. |
| 5 | No other equipment shall be utilized as an integral part of the electrical connection to the grounding wire. |
Ground faults resulting in business interruption
This section describes the phenomenon, impact on the system, possible causes, tools required for troubleshooting, precautions, and steps to be taken when a ground fault causes a business interruption.
Phenomenon
A large number of single boards on equipment at a site are reset at the same time, and service is interrupted.
Impact on the System
A grounding fault can cause service interruption.
Possible causes
- Cause 1: Poor grounding of PGND and BGND, grounding resistance greater than 10Ω or potential difference greater than 0.5V.
- Cause 2: PGND, BGND and AC zero line are common ground.
- Cause 3: PGND of the docking equipment is not jointly grounded.
- Cause 4: Poor grounding of relay cable.
PGND (Protection Ground) refers to the protection ground and BGND refers to the power ground or working ground.
Tools, meters and materials
- Multimeter
- Screwdriver
You can use the meter to test whether the grounding resistance value of BGND and PGND is in line with the index requirements, and you can also use the meter to check whether the waveform of the docking signal is deformed and distorted.
Operation Procedure
Grounding specifications for the equipment and trunk cable can be found in the "Equipment Grounding" section of the Installation Guide.
- Check that the grounding strip in the user's room is making good contact. If good contact is made, continue to the next step; otherwise, re-ground.
- Check that the transmission equipment cabinet is making good contact with the room's grounding strip. If contact is good, continue to the next step; otherwise, re-ground.
- Check that the front and side doors of the cabinet make good contact with the cabinet. If contact is good, continue to the next step; otherwise, re-ground.
- Check that the subracks are making good contact with the cabinet. If contact is good, continue to the next step; otherwise, re-ground.
- Check that the signal cable is well grounded. If the grounding is good, continue to the next step; otherwise, re-ground.
- Check whether the grounding of DDF and ODF is good. If the grounding is good, continue to the next step; otherwise, re-ground.
- Check whether the grounding of the network management equipment and various electrical equipment is good. If the grounding is good, continue to the next step; otherwise, re-ground.
- Check whether the docking equipment is jointly grounded.
Reference
None.
The technical information in this chapter and the related SDH equipment troubleshooting process are provided by Shenzhen Optical Transmission Network Technology Co.(www.opticaltrans.com), please retain the reprint. Huawei SDH optical transmission equipment, SDH transmission equipment sales phone: 13430988088 Welcome to call!
