Mains failure

[Dave Plowman (News]

Next door neighbour - a widow of 89 who lives on her own and is getting pretty frail, had a total power failure yesterday morning. And couldn't summon help as both her phones are cordless, and no mobile. So was only discovered when her daughter visited that evening, as she does every day.

Turned out to be the supply into the house which had failed. So UK Power Network supplied a generator, which arrived sometime in the middle of the night and is thrumming away nicely now.

As it happens I know a bit about her wiring. Some years ago I installed the cordless phones for her. As the cabled one was in the very cold hallway. Put an extension BT socket in the lounge and also a mains socket for the base station since there wasn't one handy. The second one went in her bedroom, I was told. Left the original phone in the hall, still working normally.

Now the ring main had been installed by her long dead husband. Mainly surface wired with those 50s surface MK sockets. Only earth in the house to the water main. Rest of the wiring ancient - porcelain fuses with separate breakers - the usual mess of added things. Very likely dating to well before WW2 - although light switches had been replaced by modern ones.

So wondering if the supply, once replaced, will be re-connected?

[Jack Harry Teesdale]

Much depends on wether UK Power need to enter the property to reconnect the supply after restoration.

ISTM that some essential remedial work on the 'earthing' may be required particularly if PME is connected.

Generally from what you have mentioned, a rewire would seem to be desirable but i doubt if UK Power could insist on this before reconnection.

[Dave Plowman (News]

They were in the cellar where the fusebox etc are last night - by the light coming from the grill on the steps to the front door. If it is a connection fault between the house feed to the street feed, surely they'd replace the ancient cable to the house anyway?

No PME round here.

OK.

[Scott]

Why did your neigbour not use the phone in the hall to call for assistance?

I have spoken to my friend (now retired from another electricity company). He says it would have to be pretty bad for reconnection to be refused. They are likely to carry out a basic insulation test and if this is bad, the system could be deemed unsafe. The most likely outcome is for the supply to be reconnected with an 'advisory' on work to be carried out.

To my surprise, he also said that provision of a new earth is chargeable and earthing in itself is unlikely to prevent reconnection taking place.

[Jack Harry Teesdale]

That depends what the fault is, if it is just a dilapidated service cable they may replace it but if it is a failed joint at the street cable it would just be repaired in the street.

[Dave Plowman (News]

Remember noticing it had been removed. It was on a phone shelf, that may have fallen off the wall.

[Martin Brown]

Probably forgotten it was there. Frail elderly living alone should be encouraged to get a Care on Call installation (monthly fee applies) so that they have a pendant to use in the event of a fall or whatever.

What might happen is that they reconnect but with a reduced capacity main fuse. Someone I knew was in this bind for getting a smart meter installed. The guy installing it told him that once he made any changes at all he would have to downgrade the installation to ISTR 40A main fuse because of the age and decrepitude of the house wiring. Still round pin plugs about - weird hybrid mix of sockets and not many of them.

I thought they did an earth bonding return test with some maximum threshold that was acceptable. Likely that an old metal cold water main bonding will easily pass though unless very corroded.

[Jeff Layman]

This doesn't bode well for when the copper wires go and we all have to use VoiP for a fibre connection. How long will a backup battery will be required to power the phone/router when the power goes down? How long will a battery support a personal alarm receiver?

[charles]

My father had one which was very useful when he slipped and fell, then unable to get to his feet by himself.

[Scott]

And will the telecoms provider meet the cost?

[T i m]

Quite some time. My old NTL cable router requires 12V @ 1.5A so worst case that's ~20W. A fairly common UPS would be ~600VA so ~15 hours (down to 50% DOD?) maybe 10 if there was an Ethernet switch involved or 8 if you included a DECT / VOIP phone?

Some (most / all?) are already battery-backed anyway (Mum's is).

Cheers, T i m

[Chris Green]

You're not comparing the right things! A 600VA UPS can provide up to

600VA, that's *power*, it doesn't tell you for how long it will provide that 600VA. Usually a domestic/computer UPS will only provide its rated (i.e. maximum) power for 20 or 30 minutes to give you enough time to shut down gracefully.

[GB]

The one MIL had (and absolutely refused to wear!) required mains electricity.

[GB]

My aunt, OTOH, refused to wear hers inside the house, but religiously wore it when she went to the shops.

[Robin]

AFAIK the requirement on telecoms providers is still that customers gave the means to make calls to the emergency services (999/112) for 1 hour after a power cut, but they only have to provide it free of charge for "at risk" customers. For the rest of us that may mean "get a mobile" or "buy a battery backup unit".

And the personal alarm systems I've seen all came with base units which required a mains supply and had built-in battery backup to allow them to operate in the event of a power outage.

[Robin]

Quite right: walking around trailing a mains flex would have been a trip hazard :)

[Scott]

Is 'at risk' purely a function of age or do other risk factors need to be demonstrated? I assume the person described by OP would qualify.

[Fredxx]

No

I think mine has two 12V 7Ah batteries. The UPS might also consume 5% of the rated 600VA just by providing the 240V. So no load will provide something like a little over 1hr of 240Vac. Also a Lead Acid capacity under a discharge of 1C will only get 66% of the C20 rate.

At rated output of 600W assuming PF of 1.0 I doubt the UPS would last 10 minutes at a 5C discharge rat or worse.

[Robert]

When looking at UPSs it is (or was) surprisingly difficult to find the data on the actual capacity in terms of watthours or VAhours, which for anything more than time to close down properly is what I was always interested in.

[Andrew]

Are Openreach going to dig up thousands of miles of underground copper cables that are just buried in soil and replace with fibre ?.