XPost: sci.electronics.equipment   
   From: CFKinsey@military.org.jp   
      
   On Fri, 03 Jul 2020 02:20:53 +0100, RheillyPhoull  wrote:   
      
   > On 2/07/2020 10:41 pm, Ralph Mowery wrote:   
   >> In article , presence@MUNGEpanix.com   
   >> says...   
   >>>   
   >>> Have you run this test with AC? That seems to be where the wheels come   
   >>> off. I brought up this thread to a friend and he mentioned his quest to   
   >>> repair some sort of HP true RMS meter that uses a thermocouple and heater   
   >>> to properly measure complex waveforms. I can't even guess how slow such a   
   >>> meter might be.   
   >>>   
   >>>> I had 3 or 4 of the Harbor Freight 'free' multimeters.  The ones that   
   >>>> usually sell for around $ 5.  They seem to be reasonable accurate for   
   >>>> the money.  Plenty accurate for the home user to test things around the   
   >>>> house.  I do admit that the safety issue of putting them across the 120   
   >>>> or 240 volt power wires is somewhat doubtful.  I sure would not use one   
   >>>> where I worked to put across the 480 volt 3 phase system that is  fused   
   >>>> with 200 amps.   
   >>>   
   >>> I'm pretty timid with anything upstream from a plain outlet. I had an   
   >>> edison base fuse burst in my hand once. Never seen one come apart before.   
   >>> It was just a 120v lighting circuit, but right off the service panel.   
   >>> There's way more excitement near those things.   
   >>>   
   >>>   
   >>   
   >> I have not ran any tests for AC . The things I work with don't care   
   >> about very much about being accurate to more than around 5 %.  Usually   
   >> it is more of do I have a voltage/current or not.   
   >>   
   >> When I work on most anything other than low voltage (below 100 volts) I   
   >> ues either my Simpson 260 analog meter  or a Fluke meter that is rated   
   >> for cat 3 and 4.  If you have not heard of the Cat numbers, they are for   
   >> devices used in different power circuits.  I don't know the numbers off   
   >> hand, but it goes something like this, Cat 1 is for low voltage items,   
   >> Cat 2 for things like stoves and refrigerators, Cat 3 for homw   
   >> wiring,and Cat 4 for the very high power circuits like I often worked on   
   >> like the 480 volt AC and 300 amps.   
   >>   
   >> For a real scare you should see some of the safety movies that Fluke put   
   >> out.  They show under test conditions what can hapen to inexpensive   
   >> meters and their meters under different conditions  like having the   
   >> meter set for amps and putting across a 480 volt circuit that has plenty   
   >> of amps .   
   >>   
   > Ahh the old "Leaving it on amps" trick. How many of us can say they   
   > never did it ?   
      
   I find it crazy that you can select volts and have the wires in the amps   
   holes.  The switch should change the contacts.  I've broken a meter doing   
   that, just measuring the voltage on a car battery.  £100 meter, but UNFUSED   
   FFS!  At least the mA range was    
   fused, but they couldn't be bothered putting in a 20A fuse for the big   
   range....   
      
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