Q:How do we provide earthing for PABX system and for the PABX equipment?
Are they two different items?
Posted Answers
Wed, 03/12/2008 - 10:16 — s-person
Correction made-:) If all the metal chassis connect with eatch other, there should not be any votage difference between them. If all the equipments were earthed using one link, it created a single point of failure. However, if the equipments are all earthing to the common ground seperately, the voltage on the equipment should be zero all the time. If you connect all the equipment together and earthing them seperately to the building earthing system, this gives all equipment with multiple earthing connections. (Not necessary but nice to have.)
Answer by s-person
Wed, 03/12/2008 - 08:10 — gallon
Yes, agreed. Actually I mean it is said that all metallic enclosures in the vicinity of each other should be bonded together to achieve equipotential bonding, which helps prevent electric shock. What is your opinion?
Answer by gallon
- 1 read
Wed, 03/12/2008 - 07:09 — s-person
Doing earthing through another device is not safe for device and people. The purpose of earthing is to route extra electricity to the earth in case of in-balance in the circuit (most of the time it should be zero). Because, if you connect the earth line to another device, the extra electricity will be passed to another device, which may or may not pass to the earth properly.
Answer by s-person
- 1 read
Tue, 03/11/2008 - 20:19 — gallon
Dear S-Person, Thanks. The picture you drawn seems the way they wanted in the brochure I mentioned. But I have seen many installation where there is a continous bonding of one matallic enclosure to another and then to next and so on.... and then finally to earth. Is that also correct ? I think this way they get equipotential bonding. Any comment from yourself pls.?
Answer by gallon
- 2 reads
Tue, 03/11/2008 - 18:55 — s-person
I believe it means that:
1. You should connect your PBAX earth line directly with your building earth/ground system. 2. All equipments should connect their earth system directly to the common building earth system - you should not connect one equipment's earth to another equipment's earth line before going to the common bilding earth system. It sounds strange, let me try a picture:
Right way:
PBAX earth system -> common building earth system
Any other equipment -> common building earth system
Wrong way:
Another equipment earth -> PBAX earth -> common building earth system
Answer by s-person
- 2 reads
Mon, 03/10/2008 - 20:35 — gallon
Actually I need to understand this note in a brochure- "PABX system earthing are to be conected to building earthing. But then says- "No other equipt to be bonded to PABX earthing". My concern is that many other equipt are bonded to building earthing which is bonded to PABX earthing also. So all are bonded again, then how to achieve the second note above?
Answer by gallon
- 1 read