Recommendation L.4

1.     Add the following paragraph to point 3:

       An electric spark detect method or a voltage resistance  test  method
with the cable submerged in water is effective if a test on  the  protective
cover  is  necessary  in  the  manufacturing  process.  In  the  process  of
installation and operation, if the factors that might cause damage to the protective 
cover or the decreasing tendency of the protective cover insulation resistance 
are to be found, the test should be carried out and  the  faults  should  be
eliminated.

2.     Replace point 4 by the following:

       The anti-corrosion of aluminium sheath should depend mainly on a high 
quality protective cover. However, if there is any factor serious enough  to
damage the protective cover, and particularly if the possible damage over the 
protective  cover  is  unable  to  be  fully  recovered  to   its   original
specifications after repair, the cover should be protected with special measures such as 
sacrifice anode electrical chemical protection.  Aluminium  alloy  sacrifice
anode which has the advantage of a higher current capacity per unit weight, an 
appropriate protective potential, abundant raw material resources and ease of 
manufacture, if an effective measure to protect aluminium  sheathed  cables.
Tests show that good results can be obtained if the protected aluminium sheath 
potential value against ground is limited within the range of -0.85 - -1.20 V 
(relative to Cu/CuSO4 electrode).

3.     Add new point 6 as follows:

       If there are no special requirements in using aluminium  sheaths  for
optical fibre cables, the same sheath material and manufacturing process may 
be used as for metallic conductor cables.


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