use of galvanised steel water pipe as connection material

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I have encounted the use of galvanised steel water pipe as a connection to a disconnector in a lv substation, has anyone had experience of this and knows a reference to calculate the current carrying capacity.

 

[cuky2000]

Galvanized steel water pipe is a good grounding electrode. However, there is concern regarding the loss of material by corrosion to maintain the galvanized pipe integrity for long time. An overside pipe (probably 3/4" or 1 ") may be OK.

Even though the following info is not for water pipe application, this guideline could be use for reference regarding ground rod useful service life as follow:


- 3.9 mil zinc coating: 10 years. (Not recommended for deep driving applications).
- 10 mil copper coating: 40 years. Acceptable for deep driving applications.
- 13 mil copper coating: 50 years. Recommended for deep driving application.

For additional details see the enclose site.

http://www.erico.com/products/GalvRods.asp

_{NOTE: If this project requires meeting the NEC, here is a quote applicable to galvanized solid steel rod:
Paragraph 250.52.A.5 of the 2002 issue of the NEC Code states that if a galvanized ground rod is to be used it must 1) be 0.625 inches in diameter minimum and 8 feet long or 2) listed! Since nearly all manufacturers of galvanized ground rods have produced to an old and outdated ANSI C135.30 document, the diameters have been well less than what the code mandates (other manufacturers have acknowledged that a diameter tolerance of +/- 1/32” has been considered acceptable).}

 

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thanks for the response, I am familiar with the use of galvanised pipe for electrodes, but the issue I am dealing with is diiferent in that the piece of pipe is forming part of a continuous electrical circuit within a substation i.e. there is significant power flowing all of the time as opposed to in an earthing the electrode.
It is easy enough to get hold of conductor current capacity for copper or aluminium conductors, but I am not sure about steel, instinctively I think that it seems like a bad practice, but a utility is commonly using it.