lineColor: String

Sets the color of Scale Break lines. Scale Break line color can be a “HTML Color Name” or “hex” code.

var  chart =  new  CanvasJS.Chart("chartContainer",
{
 .
 .
 axisY: {
      scaleBreaks: {
	      lineColor: "blue",
	      .
	      .
      }
 },
 .
 . 
});
chart.render();