If an electrical circuit can conduct current, we say that it has electrical continuity. It is also considered a closed system.  For example, when an alarm clock is plugged in and turned on, it is part of a closed system which has continuity.  If the user unplugs or turns off the clock, the system has been open and no longer has continuity.  There are several devices on the market to test for continuity, but they must be used properly to prevent electric shock.

Most people first notice a problem with their electrical continuity when their plugged in devices are no longer working.  There are, of course, many possible reasons for this.  It's always a good idea to plug the device in question into a different outlet at the opposite end of your house to check that it isn't a problem with your device.  Check your circuit box to see if any circuits have broken; reset any that have and try the outlet again.

Problems with electrical continuity can become serious.  Unintended breaks can result in electrical fires or damage to electrical equipment.  So it is important to call an electrician to check the wiring in your house if you experience frequent problems with continuity.

<a rel="nofollow" onclick="javascript:ga('send', 'pageview', '/outgoing/article_exit_link/5485288');" href="/links/?u=<a rel="nofollow" onclick="javascript:ga('send', 'pageview', '/outgoing/article_exit_link/5485288');" href="/links/?u=http://www.totalindustrialsupply.com/Continuity_Tester_p/409-69133.htm">Simple continuity testers</a> are available for consumers to test continuity of there devices.  They generally have two electrical probes and a light indicator.  When these probes are touched together, they form a closed circuit and the light indicator turns on.  When they are not touching, the circuit is open and the light indicator remains off/dark.  You should always check that your continuity tester is working before using it by touching the probes together and confirming that the indicator lights up.  

If you need to check a circuit for continuity, first cut off the power to the circuit.  You can do this by unplugging the device or turning off the main circuit breaker.  To be on the safe side, it is best to do both.  This is an extremely important step.  Failure to cut off power to the circuit could result in severe electrical shock or death.  After you have turned off the power, turn on your continuity tester and place one probe at each terminal of the circuit you are testing.  If the lighter indicator does not light up, there is no electrical continuity and you should call an electrician.  If the lighter indicator does light up, there is electrical continuity.

You can also check for continuity with a multimeter.  When the system is closed (has continuity), the meter should read zero.  When the system is open (does not have continuity), the meter should read infinity.  Check your meter before using it by touching the probes together.