2015 Q8 Protecting hazardous location

[PJW]

Another I have been sent recently; not sure if I am going to find time to review in remaining time so posting here in case anyone else gets the chance.
Bear in mind also that the IRSE Forum is disabled during the period of the exam and this year Australia is undertaking upon FRIDAY rather than Saturday and indeed Aus time is ahead of the UK so that implies and earlier than usual shutdown.  Every year there is a surge of interest last minute and in 2017 it seems more pronounced than usual.

[sowmya.ael@gmail.com]

Please find the review of the attempted answer by PJW which was to sent me through Email.
Even though he couldn't give very detailed comments due to time constraint, this will surely be useful to gather some additional points/correct the mistakes made.

Thank You PJW for your time and efforts put in to guide us.