[aprssig] Electric Field Sensor (XMAS lights)?

KF4LVZ aprssigZbr6 at acarver.net
Sat Dec 5 22:56:12 CST 2015


On 2015-12-05 17:19, Robert Bruninga via aprssig wrote:
> Sorry for the off topic.
> 
> Will one of these cigar sized (yellow) electric field sensors be any use
> in  finding the bad bulb in a series XMAS light string?
> 
> It beeps in the presence of an electric field and detects AC about 6 inches
> away.th this?
> 
> I can find no difference all along the string.  But then this is a 3 wire
> string with a receptacle on the end so there is AC end to end, even though
> there is a series bulb out.
> 
> Maybe this technique will work on a 2 wire loop string and not a 3 wire?
> 
> I'm happy to cut off the end plug and pull out the 3rd wire if someone
> claims it will work on a 2 wire string.
> 
> Sorry for the off topic post, but I'm probably not the first one with this
> dumb question at this time of year.

Yes, a field sensor will work to detect the broken circuit but, if you
get the kind that uses a very small blade antenna (insulated white blade
meant for poking into the slots of an outlet) then you don't have to cut
the string to make it work, you just have to spread the wires out a bit
and probe the one after the socket.  You should get one that has the
lowest detection limit possible (many are 50 V or higher).


Example of one:
http://www.greenlee.com/products/DETECTOR%2540cVOLTAGE-NON%2540dCONTACT-%28GT%2540d12A%29.html?product_id=28869

Low-voltage version:
http://www.greenlee.com/products/DETECTOR%2540c-NON-CONTACT-%2812%2540d90V%29-%28GT%2540d15%29.html?product_id=19153

Note the small blade tip with the tiny antenna inside.  This is what you
want.

The other thing you need to do is wire a special extension cord that
only has the single hot wire (no neutral).  This will make it easier to
trace the signal.  It's not absolutely necessary but it helps.




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