Why do energy saving bulbs flash even when turned off?

Question

Sometimes our energy saving bulbs flash every few seconds even while the power is off. When I asked our electrician about this, he said it's quite common and doesn't indicate any wiring defect such as faulty insulation. But he couldn't offer an explanation. What's going on?

Answer 1

I'm not sure, but I would hypothesis that since they are fluorescent bulbs they can turn on from magnetic fields.  

I've attached a link to a picture where someone stuck a bunch of the long tube light bulbs in the ground underneath power lines.  The field generated by the power lines will actually light the bulbs (looks pretty cool).  If yours are flickering maybe lightning ?

Answer 2

I never saw one flash when the power is off. Are you sure?

The only explanation I can come up with (and that seems hokey)  is that your off-on switch is a bit leaky and lets a bit of current through to the bulb, and the electronics sees that and attempts to ignite the gas.

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