To throw one in the air for discussion...
Let's suppose sometime around December this year there was a 72 hour
solar eclipse which co-coincided with temporary national grid shut down
caused by massive solar flares etc, so no natural heat/light and no
leccy. It's gonna get might cold if this does happen..
Would it be possible to simply plug a portable generator into a socket
on ring main (plug<->plug) (genny<->ring main) in order to supply enough
power to fire up combi-boiler and pumps to provide heat and a bare
minimum of essential lighting?
And... is there such a thing as a small (portable) diesel generator that
would be happy to run on paraffin or diesel/paraffin blend as we still
have some paraffin left in the shop tank from the days of when it was a
hardware store... May as well consider putting it to some use as an
Would something like this be sufficient:
Only 44gbp exc vat and delivery, the price sounds too good to be true.
I'm not sure I could ever see me going down this route because the
idea of joining the generator's neutral and earth would frighten me
too much. I 'd be afraid of touching the generator and getting a
shock! Presumably you must only connect the N and E together if also
connected to an earth rod.
I would also be nervous about fitting a switch in the house's earth to
switch between grid earth and generator earth. I would be afraid of
the switch failing leaving me without an earth and all metal objects
going live. I seem to have a phobia about live cases don't I!
This is something beyond my comfort zone, so I will stick to using
torches in power cuts. Wouldn't gas lamps set off the (battery
backed-up) smoke alarms?
For a full house supply, it is. It's only capable of carrying a fraction
of the normal domestic supply. It'd be okay for a single ring main, and
maybe a couple of lights.
For an extra couple of quid:-
Carries four times the current and is designed for the job.
NOt really a problem if you get a qualified electrician to do it.
On Fri, 13 Jan 2012 01:32:44 +0000, John Rumm wrote:
I was wondering what he has that fully loads a domestic ring and must
be powered... Base load of an occupied house is about 1kW, call it
2kW a nominal 8A.
But of course this is in circuit all the time so has to be able to
handle the *full* load (say 20kW, 80A) when on mains...
Why should they? All they produce is CO2 and H2O no smoke unless very
badly out of kilter. The do get HOT so things near by/above might
start to smoke...
Gas lights are by far the best source of emergency light IMHO, more
light than a 60W light bulb with ease and in all directions.
Torches produce beams and eat batteries when used continusly. Small
battery lanterns tend not to have long run times and produce little
light. I do have a twin tube flourescent jobbie that lasts a good
8hrs in single tube mode with a fully charged 6v SLA battery. Also
produces a decent amount of light over a good area and will auto
switch on when connected to the mains when that fails. Handy to have
setup when the weathers a bit bad and the lights are flickering...
Uniross DL828 but it appears to be
On Fri, 13 Jan 2012 01:36:48 +0000, John Rumm wrote:
Not sure that is a good idea. Under no supply conditions you can't
rely on the supply wires still doing what they are supposed to do. If
the upstream N-E bond broke the N would then be a floating phase, in
theory your earth rod should pull that back down but you do have to
make sure that your earth rod is fully up to spec regarding impedance
etc otherwise you'll have to treat the installation as TT.
Aye, it's voltage differences that are the problem. Tie everything
together and things become safer. But note that should the supply N-E
bonding fail things can start to get "interesting" again.
Unless the house was next to the substation and/or the rod set in Marconite
deep in wet ground, I doubt you could ever hope to get down to 0.8 Ohm L-E
loop impedance. So generally if a rod is involved, best to assume TT by
On Mon, 09 Jan 2012 13:51:59 +0000 (GMT), Dave Plowman (News) wrote:
When the charged particles hit the upper atmosphere the induce rather
large ground currents not only in the ground (as in physical earth)
but also in any conductors, like those forming a power grid. Wasn't a
great chunk of NE Canada/US blacked out due to a mismanaged(*) solar
event a few years back.
Define "portable". I have a 2kVA or there abouts diesel set. Weighs
about 50kg I can just about pick it up and stagger with it a few
paces or heave it up into the back of the Land Rover. It lives on a
cheap flat bed trolley to normal moving about.
The advantage of a diesel is that you can run it on red at 90p/l (or
less) rather than road diesel at 140p/l... The disadvantage of my
cheap chinese thing is that it's fing noisy, really noisy. If I had
the cash I'd get a Honda EU20i 2kVA with propane gas kit invertor
jobbie, nice and quiet and nice clean power but my diesel set only
cost Ģ200 rather than the Ģ1200 odd for a gas Honda.
On Mon, 09 Jan 2012 14:52:05 +0000, Alan Deane wrote:
Hopefully for an hour or two and under load. Many a standby generator
has failed when actually needed in anger 'cause the "testing" was
simply start up, run for a few minutes without a load, switch off.
Barely time for the engine oil etc to get warm let alone hot, and it
doesn't test the alternator at all.
I've run it for an hour today, under load for part of that time.
I must remember to run it up more often!
Usually I hook it up to the house and run from it for a while, to ensure
everything works, and the UPS protected computers keep running during
Testing backup systems can be a real minefield - if a test on a system
supporting something that needs continuous power fails you've ended up
causing the problem the backup system was supposed to protect
Even running for half an hour may not always be enough - I came across
a report where the backup power system to a major facility failed
during a real mains power failure - initially it ran as intended, but
then the generator suddenly cut out. It was found later that the pump
which moved fuel from the main storage tank to the generator wasn't
connected to the protected power supply - tests of the system had
always stopped before the generator's local tank ran out.
It's a dangerous way to go about it no doubt and definitely not to be
recommended. However if an area unexpectedly lost power for some time
and someone had a generator lying in the garage for other purposes, then
switching off the main switch on the consumer unit and plugging in a
double ended lead at the house end first and making sure something heavy
was in front to stop it being pulled out would not be too dangerous.
It's certainly not the way to plan for an emergency, but in an
unexpected situation where being without any heating and light for an
unknown time is weighed up against a complete bodge, the bodge probably
You would also however have to consider earthing, as you couldn't
guarantee that the earth provided with your supply would remain
connected during repairs. There again, the most likely houses to lose
power are probably provided by overhead lines right to the house and
will presumably have a TT system anyway?
Indeed much better if you are planning ahead rather than reacting to a
situation that has already occurred.
On Mon, 09 Jan 2012 20:59:34 +0000, Steve Walker wrote:
Not here, I doubt there is much, if any, underground distribution
from the national grid to our meters. We have a TNCS supply, ie only
phase and combined neutral/earth come from the pole mounted
substation. There is a hefty cable running down the pole into the
ground, the other end of which is connected to one output of the
transformer to form the combined neutral/earth.
As for rural v urban I know of several people in urban areas who have
pretty iffy power. Normally down to new developments and the DNO not
really keeping up with the locally increased demand.
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