Electric fun, Kettle on - street light(s) off. Ideas?

On Sat, 06 Oct 2007 03:10:49 +0100, dave wrote:
I watched this on the evening news. The face of the reporter was a picture as they stood under the light and shouted to her husband to turn the kettle on. The kettle went click and the light went out.
The kettle is the only appliance to do it and it does it in any socket in the house.
Reply to
I saw that on the local news too. My theory is that the kettle is probably the single highest consumption device in the house, at least 2kW and probably 3kW in this case. The house and the light may be on the same spur which for whatever reason has a highish reactive impedance back to the local sub. The street light may be a single one that controls it's on/off cycle via a light detector on the top - which in turn feeds a switching circuit for the sodium lamp. The switching circuit probably incorporates a Schmitt trigger which gives the necessary hysteresis of on/off light level to ignore lighting variations at dusk/dawn. The regulation/decoupling of the internal power supply to the Schmitt trigger/switching circuit may not be that good.
Now .... assume light has already switched on, the lady then switches the kettle on which puts a large transient on her feed line (due to its reactive impedance) sufficient to couple through the supply/decoupling of the lamps switching circuit, and enough to push the input voltage to the Schmitt through its 'off' threshold - lamp goes out.
All pure guesswork but I think a plausible scenario - any other ideas?
Reply to
Icky Thwacket
The message from "Icky Thwacket" contains these words:
That for some reason on switching the kettle is transmitting at a frequency that effects the the operation of the light's control system.
Reply to
In message , EricP writes
Our porch light is triggered *on* by the light switch in our downstairs toilet. I have not noticed this happening in daylight.
The installation blurb said something about *blipping* the switch should bring the porch light on until switched off but I have never succeeded in doing this.
Line transient as has been said elsewhere.
Reply to
Tim Lamb
In article , dave writes:
That article is self contradictory.
Some discharge lamps can be very sensitive to voltage fluctuations, particularly near their end of life. The kettle could be causing a small drop in mains voltage.
Reply to
Andrew Gabriel
And you trust them not to have fixed it? You don't see the light and switch in the same shot, though I'll admit it doesn't look "a fix" unless the reporter is a very good actor. The standard of journalism in the written story is well down as well:
"Just when I go to make a cup of tea in the morning, I switch
First para indicates that the street lights (plural) go off, but the online video refers only to a single light and only shows one light. Second half of the second para contradicts the first para, street light(s) coming on rather than going off. It is a quote but surely any half decent journo would have spotted the error that destroys the story FFS!.
Bit of a dopey electricity engineer if he couldn't trace what was happening. I guess he just wanted out of there with the TV news crew hovering about.
Reply to
Dave Liquorice
The house is on the same phase as the street lights (I bet it's a fairly small street). There is a bad connection in the main splitter box feeding the street on that phase.
There's no mention as to whether the effect happens with other houses on the street, so she may be in the only house on that phase.
Kettle = volt drop across bad connection = drop out on discharge lamps
I don't know if it's still there, but I used to see houses in Liverpool with single phase wiring along the outside of a row of terraces (near Everton FC). There was a tap off the pair for each house and another tap to feed the street lights fixed to the fronts of the houses. Not the best sort of installation... :-) The volt drop at the end house must have been horrendous when the others put their kettles on.
Reply to
Tim Lamb explained on 06/10/2007 :
They usually work roughly as follows....
A quick off then back on makes the light stay on until it is reset, or until the next period of daylight.
To reset back to normal operation, turn it off and leave it off for more than 10 seconds, then turn it back on.
Reply to
Harry Bloomfield
Reminds me of the psychic dog...
This story was related by Pat Routledge of Winnepeg, Ontrario about a repair call he handled while living in England.
It's common practice in England to ring a telephone by signaling extra voltage across one side of the two wire circuit and ground (earth in England). When the subscriber answers the phone, it switches to the two wire circuit for the conversation. This method allows two parties on the same line to be signalled without disturbing each other.
Anyway, an elderly lady with several pets called to say that her telephone failed to ring when her friends called; and that on the few occasions when it did ring her dog always barked first. Pat proceeded to the scene, curious to see this psychic dog.
He climbed a nearby telephone pole, hooked in his test set, and dialed the subscriber's house. The phone didn't ring. He tried again. The dog barked loudly, followed by a ringing telephone.
Climbing down from the pole, Pat found:
a. A dog was tied to the telephone system's ground post via an iron chain and collar.
b. The dog was receiving 90 volts of signalling current.
c. After several such jolts, the dog would start barking and urinating on the ground.
d. The wet ground now completed the circuit and the phone would ring.
Which shows that you that some problems can be fixed by just pissing on them.
Reply to
ROFL ... Poor Dog!
That is one of the funniest things I have ever read on Usenet!
Thanks for sharing it.
Reply to
Its a modern system controlled by rf signaling on the mains. The kettle interferes with it. Solution.. buy her a new kettle and send the old one to the manufacturers of the control system to fix the system.
Reply to
In message , Harry Bloomfield writes
Not this one:-)
A quick off/on brings it on OK but only for the usual timed period.
I don't suppose Homebase made much profit on it.
Reply to
Tim Lamb
Hmm. Pee completing the circuit is an elaboration to this urban legend that I hadn't heard before. The usual version has the lady reporting that her phone no longer rang but that she always knew when somebody was calling because her dog barked.
Reply to
Dave Farrance

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