Earthing Systems

You can refer to architecture design criterion for details, which yhou can find in any building standardlization earthing desing criterion tool books.There are lots of the samjples.

How much area is the buiding? How much power is the building supplied?

info@ndt.cn

It depends on where you are working and the nature and use of the building.

Some places, e.g. Australia and New Zealand, require (for residential and small retail and industrial premises) that all earths are run with a particular colour wire (green with yellow stripe, or just green) to a central eathing point (located in the meter box) which is 'earthed' to a suitable conductor buried in the earth. The wire gauge is specified in the standard according to the power rating of the item being earthed. Other countries accept earthing via a metal conduit (which is not really very clever if you factor in rust and other deterioration).

There should be a national standard or code applicable to your region. There are also some well accepted international codes which you could use if there is no national code. Talk to an electrician, or perhaps an instructor at a technical college to find out what is applicable locally.

Greg

What Greg said in post #2 is correct but it also depends on what you are earthing and what the earth needs to do. If it is a just a safety earth then you can get away with the type of earth stipulated by the appropriate code in your area. If however the earth will be used for equipment like high speed computers, specialized electronic and scientific equipment, radio receivers/transmitters etc. then it's a whole new ball game. Earthing is a complex subject and how you go about it depends on what you need it to do. Can you give us more details about your requirements or do you wish to use the shotgun approach and design an earthing system that will work for all possible applications? The more important but not all the factors that effect the earthing requirements are:

Height & method of construction of the building.

Type of equipment to be earthed eg. computer, telecommunication etc.

Lightning suppression requirements.

Local building and electricity installation codes.

Type of ground building will sit on.

Local climate & weather conditions eg. rainfall, lightning, seasonal cycles etc.

Voltage and capacity of electricity supply to building.

Expected power factor of the load.

I hope this hasn't muddied the waters too much but if you give us more detail maybe we can help.