People were evacuated from the place of worship after the blaze broke out in its organ blower room, just before noon on Tuesday.
The fire caused a power outage, meaning the building has been closed since and services have been re-located or cancelled.
But it has re-opened today, with the Cathedral Kitchen cafe up and running, and offering free cake with coffees and teas.
This weekend's services will go ahead as planned.
A statement issued today read: "There are times in life when one wonders just what’s coming next.
"After the snow, more snow - after the snow, fire - and after the fire, endless electricians who, I’m delighted to report have restored power - thank you God!
"The messages of support you’ve sent have been greatly appreciated."
It added: "Thankfully the organ itself was undamaged but given that the seat of the fire was in the room which houses the organ blower, we have to make sure nothing untoward got into it before we put it through its paces."