can a power cut damage phone lines

simple question, is it possible for a brown out or black out to damage copper/ali lines?

Can't give a definitive answer but my suspicion is that a brown/black out can't cause damage to lines but that whatever may have caused the outage could.

A standard brown out caused just by a lack of supply in the system surely couldn't cause issues with the line itself (could cause issues with a router especially when full power is restored?).

A black out caused by an electrical fault that somehow arcs to a telephone circuit could potentially cause issues (maybe overloading a joint or similar?).

I hope not as there is a problem with the local power supply that is causing a lot of trouble.

So far this year we have had numerous power outages totalling over 20 hours of blackout and constant brownouts.

We had the high tension cable from the grid to the substation replaced as they thought that was the cause of the problems and we still had a blackout after that was fixed.

Now the entire neighbourhood looks like a battlefield with UK Power networks running all over the place trying to find the cause of the problem.

Since this has all started I have lost fastpath on the FTTC and the interleave wanders from 8ms to 64ms depending on how bad the power outages gets.

Talking to the people that are digging the road up it is taking out the street lamps as well as the FTTC cabinets.

It has now got to the point where I have bought a UPS to stick my PC/NAS and router on just to try and protect my equipment as I lost my printer to one outage as when the power came back on the printer threw a wobbly and gives me a "power" error message on the LCD screen.

Your fastpath issue sounds more like RF intererence from the electrical happenings rather than actual power surges down the telephone network.

The cabinet hardware has battery backup and will be surge protected etc

There's a lot of interference out there - during a recent power cut my APC battery kicked in and Noise Margin jumped from 4.0 to 16.0 (on ADSL2+) and stayed there until the power came back a couple of hours later, then back down to 4.0, strangely in 2 steps; presumably some equipment along the way takes longer to power up.
Should have re-sync'ed the router to see what speed I could get up to!

Don't blame all gain on interference in the power grid...

Every other user of ADSL would have lost their connection entirely - you were probably the only one who had their modem on a UPS. That would mean there was no interference coming from anyone else's broadband, as well as no interference from power supplies.

Interesting thing since I moved the FTTC modem/router from the surge protect to the UPS. (Draytek 2750n)

The noise margin on both the up and down have gone up 2 dB and the downstream FEC error rates have dropped by 90%.

What ever is going on with the local power seems to be affecting the router itself as opposed to the phone line.

Oh well it seems it wasn't a complete waste of time.