title: Pandas - Keep format as hours throughout column
body: <p>I have a dataframe that has several "total hours" columns. My problem is when these accumulate over a 24 hours it starts formatting the data as <code>1900-XX-XX 00:00:00</code> to account for years, months, and days. I just want it to display total hours, even if it's in the thousands of hours. How can I do this? Below is a sample of the df currently where you can see line 5 has the issue:</p>
  
  <pre><code>    DATE        HOURS RUN               ACCUMULATED HOURS (PER JOB)     TOTAL ACCUMULATED HOURS
  0   2019-11-19  04:30:00                04:30:00                        04:30:00
  1   2019-11-20  04:00:00                08:30:00                        08:30:00
  2   2019-11-21  05:00:00                05:00:00                        13:30:00
  3   2019-11-22  03:00:00                03:00:00                        16:30:00
  4   2019-11-19  1900-02-19 00:00:00     1900-02-19 03:00:00             1900-02-19 16:30:00
  0   2019-11-13  01:15:00                01:15:00                        01:15:00
  1   2019-11-14  01:40:00                02:55:00                        02:55:00
  </code></pre>
  
  <p>The expected output for line 5 is:</p>
  
  <pre><code>    DATE        HOURS RUN               ACCUMULATED HOURS (PER JOB)   TOTAL ACCUMULATED HOURS
  4   2019-11-19  1200:00:00              1203:00:00                    1216:30:00
  </code></pre>