Energy Saving Bulbs Flashing When Off

[Andrew Gabriel]

I worked for a US company and was regularly going out there. We had to have credit cards with no credit limit in case we needed medical treatment whilst out there (and yes we had medical insurance cards too). If you do end up using your credit card, a hospital won't treat you without reserving something between $5000-$10000 against the card, and you may well not have that credit available on your normal credit card.

A friend (not with the same company) was on holiday in the US with his wife. She felt faint one day and they went into hospital, where she was put on a drip for half a day whilst they did some tests, but found nothing wrong. That cost them £5000, and that's 10 years ago. Insurance repaid it, but if they hadn't been in a position to come up with £5000 instantly and the medical problem had been more serious, things could have got nasty.

[The Natural Philosopher]

All of mine do.

Thats the trouble with running earths to them. Nice capacitative leakage path to earth.. Can still happen with switched lives though if there is an unswitched live running parallel.

[The Natural Philosopher]

Megohm, d*****ad. Its an ohm and a mho. Size matters in terms of the 'M'

[The Natural Philosopher]

They use two wires. Balanced input. Body shunts the input. Relatively low impedance source.

Of course. They are designed to. They still hum, but a comb filter or a

50Hz notch filter takes out most of the mains generated crap.

[Huge]

Anyone who travels to the USA without an adequate level of insurance is mad.

BTW, I have sought medical attention in the USA twice. On both occasions it was (i) way superior to here & (ii) free.

[Steve Firth]

My (UK) dentist still refuses to believe me when I tell him that I receive better treatment in Germany (Wiesbaden) from a private dental practice at lower cost than I do in the UK.

[Huge]

Dentistry is screwed up in the UK.

ObDIY: And not really amenable to DIY. Although my "visiting Third World Shithole" pack contains something called "The Emergency Dentist" (DIY emergency fillings made of epocy resin) my dentist advised against using them since he said they are sometimes difficult to remove.

[Dave Liquorice]

Non conventional wiring then. There is no need to have a neutral in the switch just the permenant live incoming and switched live out going.

[boatmandave]

Thanks for the tips about adding a resistor, i will give it a go tommorow and let you know how it works. And err kinda thanks for all the other stuff regarding trips to america and whatever else was covered here :-/

[Owain]

Not *un*conventional though, in the sense that it is perfectly permitted and compliant with legislation. Looping at the switch is probably more used in commercial installations though.

Owain

[Nick2]

For ECGs most of the crap comes from muscle activity (IIRC). The ECG signal itself uses fairly narrow frequency ranges so can be quite effectively filtered out from the crud.

Plus, the skin is roughened (removes the hi impedance dead stuff) before conductive gel is applied to lower the impedance. (Well it was in the 80s, dunno about now)

[Matt]

Hence the obvious typo in "the land of the free and the home of the brave" :)

[Jonathan Schneider]

I looked into my landing light doing just that a few months ago.

What I found was that it is wired slightly unconventionally though not actually unsafe (except for maybe two lives at the bulb).

Usually the live goes to the first double throw type switch then the two possible-lives, if I can call them that, go to the other such switch. Now when the light is off you have an open circuit.

See the poor ascii art but in my house each side of the bulb goes to the middle of a switch so switching it between L and N. So when off you have a closed circuit, and a loop of several square metres that will pick up all manner of radio and rectify them in the bulb until the voltage reaches something to make it flash.

L---- ---L --sw-------bulb----sw-- N---- ---N

I swapped it for another seemingly identical bulb that doesn't flash anything like as much. Also it only bothers me in the summer when the bedroom door and just about everything else is open.

Jon

[Andy Wade]

[Quoting order changed]

Are you quite sure - that's *very* unconventional?

Unless you live next door to a high power LF, MF or HF transmitting station I find it very hard to believe that that you would pick up enough voltage on your 'single turn loop antenna' to flash the light.

Apart from the possible danger you mention of both lampholder terminals being live when the light is off, there is also the risk that an arc at the switch contacts - as you switch the light off - will propagate and turn into an arc between the L & N feeds, resulting in a blown fuse/tripped MCB and not doing the insides of the switch an awful lot of good.

[Jonathan Schneider]

Yes. I didn't believe it at first but after staring at the switch wiring (which is coloured appropriately for the configuration) and entry into conduits I removed both switches and bulb and confirmed both ends have a live.

Jon

[Andy Wade]

... which is?

Conventional 2-way switch wiring using 3-core & E between the switches also results in a permanent live at each switch:

L1 L1 0===========0 0===========0============= L (in) | \ / | C 0================================O C \ / \ / 0===========0 0===========0============= Sw L (to lamp) L2 Optional L2 Intermediate

[Diagram credit: Dave Plowman]

[Jonathan Schneider]

Well that's different. I always thought it was

o===========o L in=====o------ ------o=======L to bulb o===========o

though have to say the IEE onsite guide agrees with you.

Jon

[Andy Wade]

That's the other way - more suitable if you're wiring with singles in conduit, rather than multi-core cables.