How many ACS712 do you have now?
These two lines
String tools[NUMBER_OF_TOOLS] = {"Miter Saw","Table Saw","Band Saw"}; //, "Floor Sweep"
int voltSensor[NUMBER_OF_TOOLS] = {A1,A2,A3};
Show which sensor is assigned to each tool.
These lines:
for(int i=0;i<NUMBER_OF_TOOLS;i++)
{
if( checkForAmperageChange(i))
{
activeTool = i;
exit;
}
if( i!=0)
{
if(checkForAmperageChange(0))
{
activeTool = 0;
exit;
}
}
check for the tool to be turned on.
If the one ACS712 you have is wired to A0, it will not cause the DC to turn on. Try plugging it into A1.
The program also has lots of output to the serial monitor. Can you post some using code tags.