The EC regulation and procedure is intended to be used sparingly, when your study or assessment is severely affected by circumstances. That said, you can submit multiple EC claims, as circumstances dictate.
If you have submitted several EC claims in a short period, your School may ask you to attend a meeting (e.g. with a Personal Tutor, School Postgraduate Student Adviser (SPSA), or Support & Wellbeing Officer) to explore your support options. This may include referral to specialist services or considering a voluntary interruption of study.