I have read the manual for my new multimeter but unsure which (red) terminal to use for what. The meter has one VΩmA fused 500 mA max terminal and one Unfused 10A Max terminal. I just want to measure the voltage of a wall outlet. Which terminal do I use? It would be great with some examples of what the 10A terminal is used for as opposed to the VΩmA terminal. I'm not an electrician by any means so the manual is not covering this.
3 Answers
Stay away from the 10A terminal. That is for amp measurements ONLY, and creates a dead short between the 10A terminal and the common. This will blow your fuse, burn up your probes, and/or destroy the meter. Never use that unless/until you know exactly what you are doing.
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Keep in mind that using a meter that's not rated for the task can be dangerous! Even with relatively low risk things like residential receptacles.
Right off the bat - if you got this meter for free with a purchase of a blue tarp at Horrible Freight, just throw it out.
Next, make sure the meter is properly rated for the task. Meters have CAT ratings roman numeral I through IV, and are designed for safe use depending on the application. For residential receptacles, it should be marked CAT II, and should be from a maker you trust to properly rate their products. (Hint - reputable makers don't give away meters free with a blue tarp.)
Technically, for CAT II the receptacle should be at least 30 feet away from the electrical panel supplying the receptacle; if it's right close to the panel that feeds the receptacle, you are supposed to use a CAT III rated meter.
In the comments, the original poster links their meter's web site and looking at the picture below, you see that it is rated CAT II so it's suitable for the purpose. (It also shows that the left jack, for 10A current measurements, is actually fused, not unfused as stated in the original post - which makes sense, and is a relief.)
So to measure voltage, yes you want the red lead plugged into the jack labelled "VΩmA" and the black lead plugged in the common jack, the configuration shown in the photo from the web site.
To address an issue that's mentioned in the comments - since safety is a factor, you don't want to skimp on a meter, and a good meter is not cheap. Plus there's a little learning curve involved using a meter correctly and safely. As an alternative, for checking voltage at receptacles, consider a Kill A Watt or similar plug in device:
This measures voltage as well as power utilization and it's dead simple to use, safer than a toaster.
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Memory key: Because you want to measure voltage (V), use the VΩmA terminal.
(Also use that terminal for measuring resistance (Ω) and small currents (mA).)
The 10A terminal is special purpose, only for measuring very high current (up to 10 amps).
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