multi meter

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  #1  
Old 01-09-05, 02:34 PM
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multi meter

if its allowed,im new here,could someone recommend a good nicely priced multi meter...i would love to test to see if my wiring is grounded.i have a 2 wire bx system,and im told the metal bx is the ground...would just like to test it ..thanks
 
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Old 01-09-05, 03:02 PM
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I wont recommend a brand (just dont get a cheapie) but you dont want a digital multimeter for testing house wiring be sure to get the analog type. You can test for ground with a simple neon circuit tester.
 
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Old 01-09-05, 03:03 PM
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You don;t need a multimeter to test if the box is grounded. All you need is a two wire tester, available for about $2.00 at most hardware stores.

Touch one wire to the hot side of a receptacle (black wire), and the other side to the neutral side (white) wire. The light will light.

Now touch one side to the hot side and the other side to the metal box. If the light lights then the box is grounded. If, however, the light does not light or lights faintly, then the box is not grounded.
 
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Old 01-09-05, 03:38 PM
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thanks guys for the info...
 
  #5  
Old 01-09-05, 03:53 PM
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Hi Roger,
- I've been using multimeters of all kinds for almost 50 years and never heard that an analog is any better than digital for testing house wiring. Please explain your reasoning.

Do it Right - Do it once.
 
  #6  
Old 01-09-05, 03:57 PM
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I'm going to recommend you spend $8 on an outlet tester. They plug into an outlet and have three lights on them. Everybody should have one. It will quickly tell you not only if it's grounded but also if the polarity is correct, and will test any GFCI functions to boot.
 
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Old 01-09-05, 04:00 PM
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Nomind, are you familiar with "phantom voltage" (if not, google that term). Because a digital multimeter has such very high resistance, it can pick up voltage that really isn't there. Almost any time somebody reads a voltage of 23 or 57 or 79, it's really phantom voltage because they are testing to a wire that is floating. This can be very misleading and make most people try to solve the wrong problem. Analog meters have lower impedence and are thus less subject to phantom voltage. But most homeowners are better off with simple test instruments with lights rather than numbers on them.
 
  #8  
Old 01-09-05, 04:26 PM
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thanks john for the recommendation....i seen that tester a few years back...my grandmother needed and oxgen machine for her health in the house,and the delivery guy had to test the outlet and then he had to ground that little wire on the three way adapter to the screw on the wall plate...and that was the tester he had...thanks again..ill look on the web for one....
 
  #9  
Old 01-09-05, 04:29 PM
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You don't need to look on the web for a circuit tester. Every big box store has them, every hardware store has them, even some discount department stores have them.
 
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Old 01-09-05, 07:10 PM
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Thanks John,
- I've never heard the term before, but have encountered the effect in older houses. I usually just thought my meter was acting up and went to my backup which is analog. Now I've read up on it and am more aware. Just goes to show you can never learn too much

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  #11  
Old 01-10-05, 11:13 AM
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3 light tester

I bought a 3 light tester but then I read the article by Ken Michaels, F.D. of the Hayes Electric Co. and titled "Three-Lamp Circuit Tester: Valid Tester or Night-Light?" After reading the article, I almost threw away my tester. Is it true what he said. You can google the article name to find it.
 
  #12  
Old 01-10-05, 11:33 AM
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All test equipment can be misleading at times. The most common problem with these 3-lamp testers is that they often read hot/ground reverse when the true problem is an open neutral (a problem not even mentioned by the article). But the 3-lamp testers are generally very useful, inexpensive, mostly correct, easy to use, and probably the most sophisticated tester that many homeowners could use anyway.

The author's final conclusion is that you should use a ground impedence tester instead of the three-lamp tester. But no homeowner is ever going to own an expensive ground impedence tester, so that advice is impractical for a homeowner. Remember that the article was written for electrical contractors.

Electricians and home inspectors use that simple 3-lamp tester all the time.
 
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