Good afternoon.  I have been asked to comment on the mains supply circuit for a proposed fire alarm & fire detection installation and would welcome some advise please.  The premise in question is a 6 flat Victorian built property.  The mains intake area is within an outside basement, which seems not to be adjoining the main building.  The CIE is required within the ground floor communal lobby entrance.  There does not seem a direct route from electrical intake to mentioned lobby.  Where holes could be drilled, there is a risk of hidden electrical / plumbing services, becoming damaged.  Due to the difficulty of wiring a dedicated mains supply, is it ‘acceptable’ to wire from the local ring main circuit, with associated double pole isolation unit, and 1) making all relevant parties aware (the user, purchaser, enforcing authority or insurer) 2) completing the appropriate paperwork (design, installation, commissioning, acceptance certificates) with a noted Variation.  Thanks in advance for any guidance and advice. Brad.

I do not think this is the best forum for technical question on fire alarms you should try http://firealarmengineers.com/forum/.