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I have a bed lamp that is connected to an extension cord, which happens to be very close to me. Since I don't like the idea of electricity going past my head and body—mostly all during the night—I bought a power switch to put between the lamp and extension cord. It says in the product description that it "Draws zero power when off".

However, is there current/electricity still going through the cable when the switch is turned off?

Also, the extension cord that I bought is 125V, 15A, 1875W. Since I read in my bed around an hour every day, I was also wondering, when the lamp is on, how much current is going through the cable? Is more going through because of the high amperage and wattage?

Finally, is there even any validity at all that cables close to the body/head, with extensive repetition and long periods of time, possibly be disruptive for your health? Not to start a discussion, but in this particular case.

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  • \$\begingroup\$ Make yourself a tinfoil hat. You'll be fine. \$\endgroup\$ – brhans Feb 16 '18 at 14:31
  • \$\begingroup\$ @brhans Electric magnetic fields next to your head for 8 hours a day, every single day of the year, for multiple years, is probably hazardous to your health. No tinfoil hat needed—just being careful for one's health. I wasn't sure if there was current when an appliance was plugged but closed—hence, why I asked. Thanks. \$\endgroup\$ – samseva Mar 28 '18 at 21:30
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However, is there current/electricity still going through the cable when the switch is turned off?

There will be negligible current flowing through the cable. There will still be a very small amount (some nano-amps i.e. billionths of amps) due to the cable's capacitance.

There will still be normal mains voltage (120 volts AC) in the cable regardless of whether anything is turned on. If you want to avoid that you have to disconnect it at the wall socket end.

Also, the extension cord that I bought is 125V, 15A, 1875W. Since I read in my bed around an hour every day, I was also wondering, when the lamp is on, how much current is going through the cable?

Take the lamp's wattage and divide by 120 (the voltage). For example, a 60 watt bulb should use about half an amp. (This is approximate, since there may be slight manufacturing variations and your actual power line voltage might not be exactly 120)

Is more going through because of the high amperage and wattage?

No, the rating on the extension cord is a maximum rating. The extension cord is designed to carry up to that many volts and amps safely without being damaged.

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In switched ON position, the power consumed through the cable will be solely dependent on the load wattage, and the cable will not pass anything more than this, provided there are no leakage current flowing out from the wire.

Proximity to cables carrying low frequency power can have absolutely no adverse effects on human health.

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You do not absorb any measureable power by proximity to an extension cord whether it is conducting 50 Amps or 0 Amps.

Nor do can you absorb any power from a heating pad other than the radiated infrared heat which is therapeutic and heat like sunlight is much more than trillion ( really ) times higher frequency than 50/60 Hz.

is there even any validity at all that cables close to the body/head?

None whatsoever. The so-called researcher decades ago, who reported correlation of health issues and proximity to the breaker panel and distribution of wires close to bedrooms in order to get more research grants was convicted of fraud a decade later.

Technically , when there are electric fields , the energy of the field say at constant levels is proportional to the frequency so 60 Hz is far less than 60 MHz at the same line levels which is far less than 60GHz. Although we can conduction electricity weakly the induced electric fields far below heating levels which are far below destructive ionizing levels that one might be concerned about. Like standing directly in front of a 10kW cell tower antenna which are strategic placed on roof tops to offer safe levels of radiation to nearest recipients for public safety. The signals you are worried about are more than billion times smaller. We are effectively transparent to your unwarranted feared hypothetical levels of energy.

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Health effects of electric and magnetic fields summarized in a UK government report.

There are a number of studies showing a possible link between exposure to magnetic fields in the home (and/or living close to high voltage power lines) and a small excess of childhood leukaemia. It is estimated that 2 to 5 cases from the total of around 500 cases of childhood leukaemia per year in the UK could be attributable to magnetic fields.

However, the magnetic and electric fields from a mains cable are far less than from (say) an electric motor or heating element. I would worry more about electric blankets than cables.

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    \$\begingroup\$ What does "showing a possible link" even mean? \$\endgroup\$ – pipe Feb 16 '18 at 8:26
  • \$\begingroup\$ @pipe It means some studies indicate a statistical link that is weak \$\endgroup\$ – Dirk Bruere Feb 16 '18 at 10:33
  • \$\begingroup\$ I'm really not sure if I'd be prepared to accept "The UK Government" as a reliable source. \$\endgroup\$ – Andy Preston Aug 22 at 10:33
  • \$\begingroup\$ @AndyPreston Then accept the EU, because our laws are in line with theirs on health and safety \$\endgroup\$ – Dirk Bruere Aug 22 at 10:54

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