How to Use a Continuity Tester

Updated on July 19, 2017

Before removing any device from a circuit and before accessing the internal workings of any device, you MUST make certain that you have removed ALL electrical power from the unit you intend to repair.

Simple Continuity Tester
Simple Continuity Tester
Standard Fuse Contacts
Standard Fuse Contacts

Continuity testers are simple devices designed to verify a complete electrical path through an object or circuit. They are especially useful for checking fuses of all types, lightbulbs, and wire paths.

While there are a variety of devices that include the ability to test for continuity, a homeowner can easily get by with the simple single purpose continuity tester. This is usually comprised of:

  1. Two leads
  2. A small body where the leads meet
  3. Some form of indicator

How to Test Fuses

To test a fuse of any type, remove the fuse from the de-energized circuit either by pulling it completely out or, if this is not possible, removing the lead from one side or the other of the fuse. NEVER ATTEMPT TO TEST A FUSE WHILE IT IS STILL FULLY IN THE CIRCUIT. Sometimes, the signal will backtrack through another path and give you a false reading if you leave the fuse within the circuit.

With the fuse separated from its circuit, simply touch the two leads of the tester, one to each side, to the two contacts/metal caps/sides of the fuse. If the fuse is good, the indicator on the tester will indicate this fact. If it is not good, the tester's indicator will remain immobile.

How to Test Lightbulbs

For a standard incandescent lightbulb, simply touch the two leads, one to the tip of the base of the screw portion, and one to the side of the screw portion of the removed lightbulb. If you are dealing with a cylindrical bulb (such as an overhead lamp in a car) then test it as you would a fuse. THIS TYPE OF TESTER WILL NOT WORK WITH FLOURESCENT BULBS.

LEDs require a certain level of voltage, usually just over 1 volt, to force their internal circuit into continuity. Make sure your continuity tester is designed to test LEDs if this is your need.

How to Test Wiring

You may also use this tester to verify that there is no break in a wire run. This ability is limited, of course, by the reach of the tester's leads but can be useful before making the final trims on audio wiring.

Touch one of the leads to the starting point of the unenergized wire and touch the other lead to the ending point of the unenergized wire. If there are no breaks in the wiring, the tester will indicate continuity.

When testing a wire run, it is allowable to temporarily tie in a jumper wire to one end in order to get your wiring to reach the leads of the continuity tester.

Be aware that longer wire runs may fail a continuity test with your small tester simply due to the length of the run and not because of any break in the line. For longer runs, it is recommended you use a more expensive, better-designed tester to overcome this limitation.

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    • profile image

      smitty58 4 years ago

      That is not a continuity tester!!

    • profile image

      margie100 6 years ago

      ok ok I wanted a quik answer so I called home depot and they told me the breaker in the "house" cause dryers don't have breakers that out of the way can you tell me what to do cause the the br3eaker box has only those off and on clikky thingies up and down so I don't know what to do about that please im lost

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      jess 6 years ago

      i have an amana dryer only 4 years old its heats at the beginning then cools down i see the flame light up but after 2 minutes it goes out...i replaced and cleaned my vents. pleas help

    • RTalloni profile image

      RTalloni 7 years ago from the short journey

      Hope to see more of these type articles!

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