What will cause a drop in power in a low voltage line?

What will cause a drop in power in a low voltage line?

• A. Temperature of the ground
• B. Number of wires bundled together
• C. Size of the conduit
• D. The length of the run

Answer: (D)

Voltage drop along a low-voltage line comes from the resistance the current encounters in the conductors. That resistance adds up as the current travels, and power is wasted as heat according to P = I^2R. So the longer the wire run, the greater the total resistance, and the more power (and voltage) is lost before it reaches the load. In other words, the length of the run is the main factor that determines how much drop occurs. Other factors can influence resistance a little or under certain conditions, but they aren’t the primary drivers of drop. Temperature of the ground can slightly change conductor resistance by affecting temperature, but it’s a secondary effect. The size of the conduit doesn’t change the conductor’s resistance, and bundling more wires doesn’t inherently cause a drop in the same way that length does (and in fact parallel paths can reduce overall resistance). The key idea is that longer distance means more resistance and more loss.

Voltage drop along a low-voltage line comes from the resistance the current encounters in the conductors. That resistance adds up as the current travels, and power is wasted as heat according to P = I^2R. So the longer the wire run, the greater the total resistance, and the more power (and voltage) is lost before it reaches the load. In other words, the length of the run is the main factor that determines how much drop occurs.

Other factors can influence resistance a little or under certain conditions, but they aren’t the primary drivers of drop. Temperature of the ground can slightly change conductor resistance by affecting temperature, but it’s a secondary effect. The size of the conduit doesn’t change the conductor’s resistance, and bundling more wires doesn’t inherently cause a drop in the same way that length does (and in fact parallel paths can reduce overall resistance). The key idea is that longer distance means more resistance and more loss.