Spotted on a Con Ed truck driving around Brooklyn, NY streets late at night.

Some kind of EM field sensor maybe?

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  • \$\begingroup\$ Did you tap on it? Is the rounded thing plastic or metal? \$\endgroup\$
    – Aaron
    Jun 5 at 21:27
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    \$\begingroup\$ Ground penetrating radar or something of that ilk? Does it swing downward? Looks expensive and made in small quantity. \$\endgroup\$ Jun 5 at 21:41
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    \$\begingroup\$ Ground penetrating radars are bulkier and closer to the ground. Thermal imagers would have a lens. Maybe a high-accuracy GPS? Could also be a magnetic sensor. Intriguing, hope we get an answer. \$\endgroup\$ Jun 5 at 23:03
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    \$\begingroup\$ Is there a lens opening underneath? Could it be an automated manhole cover inspection system? ntt-review.jp/archive/… \$\endgroup\$ Jun 5 at 23:17

1 Answer 1


You're looking at a Stray Voltage Detection system, model SVD-2000. It detects electric fields produced by metallic objects that have accidentally become electrified due to an insulation fault -- a lamp post, for example. There was a fatality in 2004 and a $10 million settlement. Here's a news article, and information from a supplier.

Good question! I learned something!

  • \$\begingroup\$ Good catch. We had some incidents locally about 10-15 years ago with multiple canine fatalities. I don't recall any human victims. \$\endgroup\$ Jun 6 at 4:09
  • \$\begingroup\$ Wow ! How the heck did you find that?! \$\endgroup\$
    – bigjosh
    Jun 6 at 21:05
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    \$\begingroup\$ @bigjosh Google should get much of the credit, but you have to guess the right keywords -- "Con Ed stray voltage sensor" is one winner. \$\endgroup\$ Jun 8 at 22:21

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