Around 27,000 homes in Berlin are still without power for a fourth day after an arson attack produced the second major blackout since September.It’s taking contractors longer than usual to fix the problem because the frozen ground is making it more difficult to repair the cables, while people are moving into emergency shelters or hotels to keep warm. And although the weather has amplified the impact of the attack, experts are saying it shows how exposed Germany’s infrastructure is at a time of increasing s ...