What outer layer is denoted by 'L'?

The outer layer denoted by 'L' refers to lead covered. This designation indicates that the cable is provided with a protective layer made of lead, which is used to enhance its durability and resistance to environmental factors. Lead covering can help guard against moisture, chemicals, and mechanical wear, making it particularly useful in harsh industrial settings or where cables are exposed to potentially damaging elements.

The use of lead as a protective outer layer is a well-established practice in electrical cable manufacturing, especially for cables that need to resist corrosion or where there is a need to protect against electromagnetic interference. This characteristic allows the cable to maintain its integrity and performance over a longer lifespan, thus ensuring reliable operation of electrical systems.