Electrical contract service is not covered under the definition of "auxiliary educational service". Following is the extract of the definition as per the notification [ para 2(f) ]
“auxiliary educational services” means any services relating to imparting any skill, knowledge, education or development of course content or any other knowledge – enhancement activity, whether for the students or the faculty, or any other services which educational institutions ordinarily carry out themselves but may obtain as outsourced services from any other person, including services relating to admission to such institution, conduct of examination, catering for the students under any mid-day meals scheme sponsored by Government, or transportation of students, faculty or staff of such institution;
Moreover, Finance Act 2014 has done away with the concept of "auxiliary educational services". Exemption is available only to the specified services provided to educational institution. Kindly refer Notification No 06/2014 - Service Tax, dated 11.07.2014.