I have a non-ActiveRecord server which is sending data to another service. That server expects to receive instructions including UTC in the format:
config.time_zone = 'London'
I don't think ActiveRecord should have anything to do with it, but maybe I'm misunderstanding. Like Sergio said, set your applications timezone to UTC.
Here's my Rails app. My computer is in PST. My Rails app is set to UTC.
> Time.now => 2014-01-22 21:52:38 -0800 > Time.zone.name => "UTC" > Time.zone.now => Thu, 23 Jan 2014 05:52:43 UTC +00:00 > Time.now.utc => 2014-01-23 05:52:45 UTC
I would strongly advise not overriding Time.now. That can only lead to the dark side.