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Amendment No. 2 January 2010 TO Is 3043: 1987 Code of Practice For Earthing

Amendment No. 2 to IS 3043:1987 introduces a new sub-clause on corrosion allowance for earthing conductors, highlighting that steel corrodes faster than copper in soil and providing a correlation between soil resistivity and corrosivity. Recommendations for safeguarding conductors against corrosion include cathodic protection and corrosion-resistant coatings, along with specific allowances in cross-sectional area based on soil resistivity. The document specifies minimum thickness requirements for steel conductors based on soil type to ensure stability and mechanical integrity.

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23 views1 page

Amendment No. 2 January 2010 TO Is 3043: 1987 Code of Practice For Earthing

Amendment No. 2 to IS 3043:1987 introduces a new sub-clause on corrosion allowance for earthing conductors, highlighting that steel corrodes faster than copper in soil and providing a correlation between soil resistivity and corrosivity. Recommendations for safeguarding conductors against corrosion include cathodic protection and corrosion-resistant coatings, along with specific allowances in cross-sectional area based on soil resistivity. The document specifies minimum thickness requirements for steel conductors based on soil type to ensure stability and mechanical integrity.

Uploaded by

biswasbitu
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© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
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AMENDMENT NO.

2 JANUARY 2010
TO
IS 3043 : 1987 CODE OF PRACTICE FOR EARTHING
(First Revision)

(Page 17, clause 8.6) — Add the following new sub-clause after 8.6:

8.6.1 Corrosion Allowance — On an average, steel corrodes about six times as fast as copper when placed in
soil. The extent of corrosion depends upon the properties of soil. The generally accepted correlation between the
electrical resistivity of soil and its corrosivity is as indicated in the table below:

Soil Resistivity and Corrosion

Range of Soil Resistivity (Class of Soil)


(ohm-metres)

Less than 25 Severely corrosive


25-50 Moderately corrosive
50-100 Mildly corrosive
Above 100 Very mildly corrosive

This following methods can be adopted to safeguard Conductor against excessive corrosion:
a) Use of cathodic protection, and
b) Use current conducting, corrosion resistant coating on steel (for example, zinc coating).
The zinc coating on the tubes shall be in accordance with IS 4736 : 1986 'Hot dip zinc coatings on
mild steel tubes (first revision) with coating thickness 150 microns, Min.
a) Use steel conductor with large cross-section having allowance for corrosion.
Based on the results of the field studies on rates of corrosion, the following allowances in cross-
sectional area of the earthing conductor are recommended to take the effect of corrosion into
account.

Allowances in Cross-Sectional Area of the Earthing Conductor to Take the Effect of


Corrosion into Account

Type of Laying of the Earth Conductor Allowances to be


Considered in Sizing

a) Conductors laid to soils having resistivity 0 (No allowance)


greater then 100 ohm-meters

b) Conductors laid in soils having resistivity 15 percent


from 25 to 100 ohm-meters

c) Conductor laid in soils having resistivity 30 percent


lower than 25 ohm-meters or where treatment
of soil around electrode is carried out

For the purpose of determining the allowance to be made for corrosion, the minimum resistivity of
the soil encountered at the location of grounding electrodes to be considered The. resistivity will be
the minimum in wet weather. Thus, for very mildly corrosive soils, steel conductors meeting the
stability and mechanical requirement are adequate. However, the steel conductors in the soil of other
types should be at least 6 mm thick if it is steel flat and have a diameter of at least 16 mm if it is in
the form of steel rod.

1
Price Group 3

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