A cable lead sheath is a protective layer made of lead that is used in certain types of cables, particularly high-voltage (HV), extra-high-voltage (EHV), and submarine cables. The lead sheath serves multiple purposes, including providing a moisture barrier, offering mechanical protection, and acting as a fault current path. It is typically applied as a continuously extruded metal barrier around the exterior of the cable.

Benefits and Characteristics of Lead Sheath:

Moisture Barrier: The lead sheath acts as a metallic radial moisture barrier, preventing the ingress of moisture or moisture vapor, salts, pollutants, hydrocarbons, and gases into the cable.
Mechanical Protection: It provides protection against insects, vermin, microorganisms, and limited mechanical damage.
Flexibility: The lead sheath allows for cable flexibility during installation and service operations, such as thermal expansion.
Corrosion Resistance: Lead is highly resistant to corrosion, microorganisms, gases, acids, and hydrocarbons.
Recyclability: Lead is 95% recyclable and widely used in various applications, including vehicle batteries, power backup systems, and medical equipment.
Comparison with Other Materials:

Longevity: Lead-sheathed cables have been found to last more than six times longer than cables with aluminum sheaths, based on an analysis of corrosion failure rates.
Cost Considerations: Lead is relatively more expensive than aluminum, but the total life costs of an installed cable should be taken into account when considering material costs.
Environmental Considerations:

Proper Usage: When used correctly and in specific applications, lead does not pollute the environment. The polyethylene jacket outside the cable prevents direct contact between the lead sheath and the surrounding environment.
Limited Contamination: Lead released from lead-sheathed cables is unlikely to contaminate the soil due to sorption and precipitation reactions that limit its mobility. Additionally, modern lead-sheathed cables are covered with a plastic outer sheath, further reducing the likelihood of contamination.
It is important to note that there is ongoing discussion and concern regarding the potential environmental and health impacts of lead-sheathed cables, particularly in older metropolitan areas where substantial quantities of these cables still exist [2]. Lawmakers and industry trade groups are addressing these concerns and seeking accountability from telecommunication companies [2].