Replies

1. 
   BillHartmann | Aug 31, 2007 01:41pm | #1

   May I ask, what for?

   That is not a normal piece of test equipment for construction.

   YEARS ago I was designing some test fixtures for testing flux valves.

   That was long time ago. IIRC I was trying to get a gaussmeter, but was able to design the test fixture without one.

   Our lab was over a parking garage.

   I remembered one day the meters where going crazy. Could not figure out what was going on until I realized that it was quiting time and the cars where leaving the garage and I was sensing the changes in the earth field.

   .
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   A-holes. Hey every group has to have one. And I have been elected to be the one. I should make that my tagline.
1. 
   MtnBoy | Aug 31, 2007 02:49pm | #3

   Just want it to check fields so I'll know where wiring needs some attention.

1. 
   junkhound | Aug 31, 2007 03:20pm | #4

   I use a surplus Hall effect sensor (< $5) with 2ea.  6" steel pole pieces, calibrate with wire, known current, and u0*i/d; or Helmholtz coil, which is more accurate.

   As to:  check fields so I'll know where wiring needs some attention

   Query, what kind of 'attention'? 60 Hz magnetic fields on household wiring are not affected by the integrity of the insulation. Are you installing hospital wiring near an MRI that could need shielding, etc...?  Nothing I know of in a 'normal' house would need to have magnetic fields measured, unless you have a lawyer trying to sue the power company for fields due to nearby power lines, etc. Have seen a couple of cases where a computer monitor near a welder circuit would have bad color due to the magnetic fields.

   Like Bill and Dan asked, what are you 'really' doing?  Your profile says 'arts and entertainment', are you having problems with a projection system with colors or distortion - that could be caused by electric fields from wiring near an electronic projector.

   Oh yeay, about forgot to add, you can always just use a compass, when it dont point north anymore, you got other fields.

2. 
   BillHartmann | Aug 31, 2007 03:37pm | #5

   "Just want it to check fields so I'll know where wiring needs some attention."How are you going to use the gaussmeter to determine when wiring needs some "attention"?If you are talking about a clampless, non-contact ampmeter then get a Fluke or make your own with a hall affect device..
   .
   A-holes. Hey every group has to have one. And I have been elected to be the one. I should make that my tagline.

1. 
   DanH | Aug 31, 2007 05:07pm | #6

   The meter would help identify K&T wiring, and also improperly installed wiring where hot and neutral got separated. Wouldn't do much good for regular romex, though, and most non-contact voltage detectors would work about as well at those tasks.
   So convenient a thing it is to be a reasonable Creature, since it enables one to find or make a Reason for everything one has a mind to do. --Benjamin Franklin

2. 
   MtnBoy | Aug 31, 2007 05:12pm | #7

   To detect elevated EMFs in areas where there's suspicion that wires are damaged. Handheld meter.

1. 
   DanH | Aug 31, 2007 05:19pm | #8

   Wire damage won't elevate magnetic fields.
   So convenient a thing it is to be a reasonable Creature, since it enables one to find or make a Reason for everything one has a mind to do. --Benjamin Franklin

2. 
   MtnBoy | Aug 31, 2007 05:34pm | #9

   Talking about damage that affects the cables so where they're twisted together the magnetic field cancellation is affected.

3. 
   DanH | Aug 31, 2007 05:37pm | #10

   So you're talking about CAT5, not power wiring?
   So convenient a thing it is to be a reasonable Creature, since it enables one to find or make a Reason for everything one has a mind to do. --Benjamin Franklin

4. 
   MtnBoy | Aug 31, 2007 08:05pm | #11

   Talking about the lines bringing the power in. Being twisted, the hot and neutral, the magnetic field is cancelled. Damage to that cable can uncancel it and a gaussmeter will alert you to that.

5. 
   DanH | Aug 31, 2007 09:14pm | #12

   Bullfeathers! Unless the twist is undone the meter will find nothing, even if there's a partial short.
   So convenient a thing it is to be a reasonable Creature, since it enables one to find or make a Reason for everything one has a mind to do. --Benjamin Franklin

6. 
   junkhound | Aug 31, 2007 09:54pm | #13

   You dont need a gaussmeter, it will do nothing for you.

   If you are looking for any type insulation damage, you need a TDR or a thumper.

7. 
   DanH | Aug 31, 2007 10:09pm | #14

   An electrostatic field meter might be slightly helpful, but it would take some interpretation and you'd have to be up close and personal with the cable.However, if you're determined to do this, maybe something like this would be the ticket:http://www.trifield.com/EMF_meter.htmNote that it only claims 30% accuracy on electrostatic fields, but I'd guess that you don't need absolute accuracy, just relative.
   So convenient a thing it is to be a reasonable Creature, since it enables one to find or make a Reason for everything one has a mind to do. --Benjamin Franklin

2. 
   DanH | Aug 31, 2007 01:56pm | #2

   http://www.uksmg.org/magnet.htm

   Otherwise prices seem to start around $250, I gather, and quickly get up to the $800-1200 range.

   Note that you need to sort out whether you're interested in measuring weak fields (earth's magnetic field) or strong ones (around electric motors).

   So convenient a thing it is to be a reasonable Creature, since it enables one to find or make a Reason for everything one has a mind to do. --Benjamin Franklin
3. 
   JohnD1 | Aug 31, 2007 10:45pm | #15

   MtnBoy:

   I have a feeling that you are looking for electric fields in your house on the thought that they are bad for your health.  Do you live near power lines or the like?  Or, did you recently read one of the web sites that describe the evils of electric fields?