Recommendation L.3

Replace point 8 and onwards by the following:

8.	Through-connection of armouring

In case long-distance cables or similar cables are provided with metal armouring, this should be through-connected electrically at the splicing points. This should be done to obtain maximum protection against the effects of atmospheric discharges and protection against induction.

Metal armouring on cables forming part of the distribution network should also be through-connected in case such protection is needed.

In case metal-armoured cables are also provided with a metal sheath it may be desirable to through-connect this and the armouring electrically at the splicing and/or repeater points. This should be done to neutralize any differences in potential between the armouring and metal sheath, and to obtain maximum protection against magnetic interference. Through-connection may create corrosion problems, which will usually reduce the lifetime of the metal armouring.

9.	Omission of armouring

On directly buried cables, metal armouring can be dispensed with in case the cable is provided with a strong plastic sheath, for example of polyethylene. A further prerequisite is that the soil and laying conditions should be favourable.

Additional protection, for example of optical fibre cables, may be obtained by providing the cable sheath with an external layer of polyamide (thickness 0.4 - 0.5 mm). This has a favourable effect as a wearing surface when drawing the cable over long distances. Moreover, the layer gives a certain degree of protection against light mechanical attacks.

9. 10. Corrosion considerations - cables with metal sheaths

(No change to the text.)

10. 11. Rodents and insects

Damage from rodents and insects to direct buried cables may be high in some areas. In those locations, it may be advisable to consider the application of some type of armouring. For detailed information regarding armour protection against rodent and/or insect attack, the reader is directed to Part IV-B, Chapter II of the CCITT Handbook "Outside plant technologies for public networks", mentioned in Recommendation L.1.

11. 12. Tropical countries

(No change to the text.)