diff --git a/cabledrop.py b/cabledrop.py
index 80fd4fc..fcd2009 100644
--- a/cabledrop.py
+++ b/cabledrop.py
@@ -3,14 +3,14 @@ from math import sqrt
 length = 10000.0  # feet
 current = 10.4  # Amps
 temperature = 250.0  # degress F
-k75 = 10.37  # 1.26 / 1000.0  # ohms of 1 circular mil foot of conductor
+k20 = 10.37  # 1.26 / 1000.0  # ohms of 1 circular mil foot of conductor
 circular_mils = 10384.0  # cross-sectional area in circular mils of conductor
 alpha_copper = 0.00393
 alpha_aluminum = 0.00330
 
 
 def voltage_drop(length, current, temperature, k75, circular_mils, alpha):
-    return sqrt(3) * k75 * (1.0 + alpha * ((5.0 / 9.0) * (temperature - 32.0) - 20.0)) * length * current / circular_mils
+    return sqrt(3) * k20 * (1.0 + alpha * ((5.0 / 9.0) * (temperature - 32.0) - 20.0)) * length * current / circular_mils
 
 
 def calc_voltage_needed(input_voltage, voltage_drop):