Malfunctioning Tester?


Old 02-22-19, 12:00 PM
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Malfunctioning Tester?

I have an older buzzer type continuity tester that is showing continuity where there should be none. Then I have a second digital voltage tester and when in the continuity selection it shows no continuity on the same wire which is what I'm looking for. I've shorted each tester within itself to make sure they are working and they are. Why would I be getting 2 different results with 2 different testers. Ive completely torn apart my sub panel looking for a short but now I'm not sure that I have a problem at all. Thanks for the help
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Old 02-22-19, 01:30 PM
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What is it you are trying to do...... locate a short in AC wiring ?
Every continuity tester operates at a different resistance. Some are 50 ohms or less..... some are 150 ohms or less. If there is something connected to the line you are testing for a short.... one may show continuity and one may not.
Old 02-22-19, 06:09 PM
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Continuity testers use DC and inductance loads such as a transformer and electric motor may show continuity as they have very low resistance to DC current.
Some high current resistive loads (light bulbs, heating coil, etc..) may show continuity as well because they have low resistance.

As PJmay said, threshold of continuity testers are different from manufacture to manufacturer or model to model. Using ohmmeter will give you more consistent result.
Old 09-09-19, 02:35 PM
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There are many situations where simple continuity tester with power source and bulb or buzzer can be most helpful.

Modern DVM's are very sensitive and can readings can be misleading, especially to the inexperienced.

For most 24 or 120 VAC systems situations I refer a light bulb. Bulb unlit no power, lit brightly power on, lit dimly some issue.

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