Refer to figure. 
ICAO Annex 14

5.3.4 Approach lighting systems

Simple approach lighting system

5.3.4.2 A simple approach lighting system shall consist of a row of lights on the extended centre line of the runway extending, whenever possible, over a distance of not less than 420 m from the threshold with a row of lights forming a crossbar 18 m or 30 m in length at a distance of 300 m from the threshold.

Precision approach category I lighting system

5.3.4.10 A precision approach category I lighting system shall consist of a row of lights on the extended centre line of the runway extending, wherever possible, over a distance of 900 m from the runway threshold with a row of lights forming a crossbar 30 m in length at a distance of 300 m from the runway threshold.

For a CAT I precision approach, runway must have:

• The centre line lights extend for 900 m from the runway threshold (whenever possible).
• The crossbar is 30 m long, located 300 m from the runway threshold.

These dimensions provide pilots with strong visual guidance during the final stages of an instrument approach, helping them establish and maintain alignment with the runway centre line before reaching the threshold.

Simple Precision : 420/ 18 - 30

CAT I : 900/300/30

CAT II : 900/150-300/30

(Remember, cats have 9 lives)