Final answer:
To determine the number of risers that require a light with a switch on both sides for the stairs, we need to consider the layout and regulations for stair lighting. The current and power specifications provided can help us determine the maximum allowable current for the cable used. Consulting local building codes and regulations is essential for accurate information.
Step-by-step explanation:
In order to determine how many risers require a light with a switch on both sides for the stairs, we need to consider the layout and regulations for stair lighting. According to the given information, Stairs I lighting has a current of I(F) = B6 and uses a cable type 3G1 Cu with a power of P = 120W. Stairs II lighting has a current of I(F) = 86 and also uses a cable type 3G1 Cu with a power of P = 120W.
To determine the number of risers that require a light with a switch on both sides, we need to consider the maximum allowable current for the cable type 3G1 Cu. Since we are given the current for both Stairs I and Stairs II lighting, we can compare them to the maximum allowable current and determine the number of risers that exceed this limit.
It is important to consult local building codes and regulations for specific requirements regarding stair lighting, as they may vary.