How to set a threshold / limit line to a bar chart?

[KdP_300]

How can I set a fixed limit (threshold) line to a bar graph? (Not a trendline). I want to monitor anything that exceeds the limit/threshold.

[JoeM]

@KdP_300 

There are two options - 
1) Add a plot band under the formatting. Here, you could draw a large plot around the expected range or create a thin plot that appears as a line.
2) While this isn't precisely what you asked for, you could use conditional formatting to highlight any columns that exceed a specific value.