Coiled extension cord lamp

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By Sean Michael Ragan
Posted 2009/10/14 @ 2:36 pm
Category 3D Printing, Electronics, Furniture

I love this lamp made from its own coiled extension cord by Craighton Berman. He’ll sell you one ready-made with a cord, or just the laser-cut acrylic frame and lamp guts so you can roll your own.

BY Sean Michael Ragan

I am descended from 5,000 generations of tool-using primates. Also, I went to college and stuff. I write for MAKE, serve as Technical Editor for MAKE magazine, and develop original DIY content for Make: Projects.

In the Maker Shed

Cube 3D Printer

Makey Makey Standard Kit

Telegraph Decoder Kit by Spikenzie Labs

Tux Case for Raspberry Pi

5 Responses to Coiled extension cord lamp

Damien on October 14th, 2009 at 5:44 pm said:

How warm does it get?
I realise compact fluorescent lights don’t draw much power, but what’s the likely inductance of an air-cored coil of that diameter / number of turns? Is it a possible fire hazard?

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- gear head on October 14th, 2009 at 6:55 pm said:
  
  add that to the 60W-100W bulb that some dummy will put in it because the lamp’s not bright enough and you have a nice little firestarter right there.
  
  Isn’t this the reason we have UL, CSA and BS safety standards?
  
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joe on October 14th, 2009 at 8:26 pm said:

One has to realize that this coil is not an inductor that will generate heat. When an inductor is made, you use one wire and wind it. This is using two wires and each cancel the other out therefore there is no inductance. With no inductance there is no resistance other than the normal resistance in the copper wire and in reality, there is no heat generated by coiling the extension cord. You can verify this if you want by coiling an extension cord and running a 100 watt light bulb off of it. You will find that there is no heating happening. This lamp is not a fire starter. Basics of electricity folks two wires together with current flowing in opposite directions cancel out any magnetic currents, this is why we use Romex, with the old single wire, knob and tube wiring, it was not uncommon for a single wire to heat an iron nail next to it and cause fires. When Romex was invented and used the amounts of fires caused by electrical wiring dropped. Think on this, a two wire romex cable is running from the panel to a receptacle. This romex is not unlike the two wire extension cord in the lamp above. Now this cable (romex) is fastened by a number of cable staples (iron/ steel based). Why do these staples not heat up if there is a magnet field surrounding the cable? They do not heat up because the magnetic fields cancel each other out and there is no difference if the cable is coiled or straight. Look at a transformer, same principle. I have over 40 years of electrical / electronic, data communications experience.

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japroach on October 14th, 2009 at 10:48 pm said:

Its primary purpose is an extension cord holder, second is “art”, and lamp is probably third.

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Chas on October 15th, 2009 at 2:43 am said:

Cool, yes. $75 for the kit version, no.

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