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From: John De Armond
Subject: Re: unstable, fluctuating house current?
Date: Mon, 02 Jan 2006 01:32:57 -0500
Message-ID: <>

On Mon, 02 Jan 2006 02:08:52 GMT, CJT <> wrote:

>Neon John wrote:
>> On Sun, 01 Jan 2006 08:50:51 -0500, mm <>
>> wrote:
>>>I'm pretty sure most people have never heard them called solenoid
>>>operated voltmeters.  .If you want people to understand, I'd either
>>>explain what I meant, or call them mechanical voltmeters, (or
>>>electromechanical, or wire coil, or moving needle VOMs)
>>>What is Wiggy?
>> "Solenoid meter" is the only thing I've ever heard it called besides a
>> Wiggy.  Wiggy is (I think) Square D's brand name for a solenoid meter.
>> A solenoid meter does not have a needle.  It has a plunger that gets
>> sucked into a solenoid, the depth of which depends on the voltage.  A
>> real Wiggy also has a polarity indicating magnet on top.  Some other
>> brands have neon bulbs mounted on the plunger to aid in seeing it.  It
>> is a low impedance device that does not respond to leakage current.
>> Instead of sowing confusion, why not google it?

>Then you ought to be able to use a digital voltmeter with an appropriate
>(high resistance -- not like one for a current meter) shunt to achieve
>the same result.

If you insist.  Of course, you still have to keep the meter in view
and have enough light to read it.  The Wiggy buzzes and vibrates when
energized.  After a little experience, one doesn't need to look at the
thing to see what it's reading.

Right tool for the job and all that.  I can cut down a tree with a
coping saw but with a chainsaw close at hand, why?  Wiggys are cheap
and really are the right tool for the job of troubleshooting power


From: John De Armond
Subject: Re: unstable, fluctuating house current?
Date: Mon, 02 Jan 2006 04:18:26 -0500
Message-ID: <>

On Mon, 02 Jan 2006 01:18:19 -0500, mm <>

>>Instead of sowing confusion, why not google it?
>I did.  I googled solenoid meter and solenoid meter wiggy.   I forget
>the details but didn't find anything relevant, except when I looked up
>solenoid in the dictionary, apparently it means any coil, not just one
>with a moving metal plunger.    No one I know uses the word that way,
>but I figured the OP might.

The first hit on "wiggy voltage tester" was to Home Depot ($19.95) The
second was to Square D's site:$file/wiggy.htm

>Also, why would you need a solenoid meter such as you describe, when
>it seems to me any low impedance meter would work?

Several reasons, in no particular order.  It's cheap enough to have
one everywhere, even leaving them inside machine cabinets.

It indicates if the voltage is AC or DC - quite important when a
cabinet has mixed voltages.  It's a real pisser to tie into a 250VDC
bus because your meter set to AC reads zero.

It draws enough current to burn through corroded and otherwise bad
connections while not being affected by coupled potentials, ground
loops and so on.

It covers the full range from about 50 volts to 600 without range
switching.  No digital nor analog instrument does that, at least
without range switching which takes time.  There is at least a little
response on 24vdc.  I can walk down a terminal strip in a cabinet
looking for the line voltage without worrying about high voltage DC or
even higher voltage AC affecting my meter.

I don't have to look at the thing.  I can feel and hear its operation.
I can even slip it in my shirt pocket and still feel it operate.

The Wiggy is totally unaffected by RF.  Try using a DVM (except maybe
a high end Fluke) inside a large transmitter or around an induction
furnace.  Even the venerable old Simpson sometimes acts up when the
meter protection diodes pick up enough RF.

I could probably think of a few more benefits but that's enough for
>Are you saying it has to have lower impedance than a classic simpson
>VOM for example, or any meter made in the 60's and earlier?   IIRC
>they are 30,000 or 50,000 ohms per volt.

Yep.  I can't seem to find a spec on the thing but I'd guess that it
draws at least a half amp on 120vac.  Almost all reactive power, of
course, so no significant wattage involved.  I know that the prods
draw a pretty significant spark on 480vac.

>That would be surprising to me, and the lower the imdedance the more
>the circuit is affected by the meter.

When diagnosing power circuits, that's exactly what you want.  I don't
want a DVM or even a Simpson 260 sitting there reading leakage current
through the blown fuse.  And I don't want to be chasing my *ss trying
to find out why the circuit is still "hot" despite having opened the
breaker because my meter is reading stray current coupled into the
conductor from others in the conduit.  This is a special problem when
there are lots of variable speed drives about with their high

Of course, the opposite holds too.  A Wiggy is like a bull in the
china shop inside an instrument cabinet.  I can think of more than one
nuclear plant trip caused by a spark-trician poking his Wiggy where it
didn't belong.  We actually banned Wiggys from the instrument rooms at
the Sequoyah NP.

Like I said, the right tool for the right job.

BTW, something I'd forgotten until Google reminded me of it.  "Wiggy"
is the abbreviated name for the inventor of the thing. "Wiggingham
Voltage Tester" is the formal name.


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