Electrical And Electronics Testers: SAFETY FIRST!
Never take electricity for granted! Electricity kills even at a very low amount or level. Learn the basics of safety before engaging in any live circuit testing or activities. Best of all hire yourself an electrician or technician and learn through him if you feel the need to do things yourself later on.
Electrical and electronics testers are your best bet for making sure you are not touching live circuits. TAG your circuit breakers and write a note down saying keep it turned off while you are working on a certain circuit. Let everyone know there is someone working on that circuit!!! THIS IS TRUE EVEN IN OUR OWN HOMES!
Beware of capacitors! Learn how to identify a large capacitor in a circuit! Why? Capacitors store electricity and could be a source of shock hazard!
Electrical And Electronics Testers Our Great Friends In Times Of Trouble!
Electrical and electronics testers come in very handy when our electrical equipment or our electrical power sources fail. Another way to test for power is through the use of a known good working equipment. Plug that good unit in, turn the switch on and if it runs this means there is power present at the power source. But electrical testers are very cheap and very convenient to use once you get familiar with them.
Fluke T6-1000 Electrical Tester with FieldSense Technology
The tester below combines the old clamp-on ammeter and the multimeter capabilities plus more:
a) Simultaneous voltage and current measurement and display
b) 1 to 1000 VAC or VDC (T6-1000); 600 V ac or dc (T6-600)
c) 0.1 to 200 Amperes AC
d) Resistance 1 Ω to 100 kΩ (T6-1000), 1 Ω to 2 kΩ (T6-600)
e) Frequency measurement 45 Hz to 66 Hz (T6-1000)
f) Works with wires up to AWG 4/0 (120 mm2 ) with a 17.8 mm jaw opening.
My Favorite Tester The Multimeter!
As the name implies multi-meters are our multi-function testers that are out there in the market. They can make life easy for our techs and home owners! Even for non tech types of folks who would want to do some electrical testing, the multi-meter is a great friend around the house or shop. Below is an example of a multi-meter. Available and cheapest at Amazon.com, the Fluke brand is one of the most favorite by many people around the world. The U.S. Navy uses this type of multi-meter.
Testing For Power
You plug your appliance or tools into the outlet, turn the switch on and nothing happens. One of two things could be the issue. Either the equipment is bad or the power source is faulty. Checking for power or the presence of electricity in a circuit such as our common electrical outlets is a very useful and easy step in basic electrical troubleshooting.
To test for power or the presence of electricity at your power outlets, simply set the multimeter to AC volts, always set it at a higher setting than the known normal voltage of the power source. Then insert the tester probes into the outlets. You should get the right value of the normal voltage. In the US, the common household voltage is 120 volts AC. In Europe and Asia it is mostly 220 volts AC.
Testing For Continuity
When you have proven that the power source is okay the next test is testing the equipment itself. The test is called continuity test. A continuity test is simply a test to see that your equipment has a ‘continuous’ circuit including the on and off switch. The word continuous circuit is the opposite of an open circuit. To test your equipment for continuity first make sure that you have unplugged your equipment. There should be NO POWER to the equipment!!!
Then set the multimeter to Ohms or resistance range of settings. Next you will want to test for functionality (tester working properly) of the tester by testing both test leads (red and black) wires that come with the tester. This is a test of the meter itself. A good multimeter, when set properly to test resistance/continuity/ohms, when the two leads are touched will result in a good deflection of the indicator needle if it is an analog type or give you CLOSE to Zero ohms read out if it is a DIGITAL tester.
Remember that testing for continuity of the tester itself is simply allowing a flow of current from the tester’s battery to make a successful ’round trip’ flow from one side of the battery to the other side of the battery showing there are NO OPENS in the test leads and that the meter is functioning.
After the meter is shown to be working properly the next thing is to test an equipment suspected to be faulty. An example: To test for continuity of a simple electric fan, unplug the fan, put both leads of the tester to each prong of the plug (power prongs or the ones you plug in to an electrical socket) , then turn the fan switch on. If the circuit is good, the tester will give a resistance reading in Ohms or a close to Zero reading or a good deflection on the indicator needle. This tells us that the path for current is complete and there are no breaks or open circuit conditions. This tells us that when we plug the fan into our power outlet and turn the switch on, the unit will run when there is power to the outlet and the outlet has no defects.
Testing For Current Flow Or Amperes
Overheating electrical circuits are caused by an electrical condition called an overload. This simply means that something from inside the equipment is drawing too much electrical current above the rated or specified current flow. This will eventually result in overheating and burning of electrical circuits.
Normal electrical current draw will produce a negligible amount of heat and that is not to be mistaken for trouble in the circuit.
A multi-meter has another function called an amp meter or ammeter that reads or determines the amount of current being drawn or used by a certain equipment. A popular type is called a Clamp-on ammeter or amp meter.
Remember that during the test, the equipment has to be running and drawing electricity. So BE VERY CAREFUL!!! This test is normally left to experienced and trained individuals! A clamp-on ammeter uses one out of the 2-3 power wires and clamps the clamp-on ammeter around that one wire while the circuit being measured is running or on full power. You have to know the running and starting amps which are normally indicated on the equipment. Higher current draws could be caused by short circuits, unwanted ground or a mechanical overload.
Available and cheapest at Amazon.com, the Fluke brand clamp-on ammeter is one of the best and favorite by techs and hobbyists around the world. The United States Navy uses this tester.
Testing For Unwanted Ground
ALL LIVE CIRCUITS of an electrical equipment SHOULD HAVE NO ELECTRICAL CONNECTION to the equipment metal body or else you could be electrocuted if you turn the switch on to this equipment and you are holding the equipment. The condition where a live part of the internal circuits of any electrical equipment is called an unwanted ground. ALL UNWANTED GROUND of any electrical equipment should be eliminated before any use of such an equipment. It should be made a practice to constantly check for this condition before using a heavily used electrical equipment such as hand tools like electrical drills etc.
Unwanted grounds can cause a small to a massive amount of electrical current to flow to the casing and to the user. This is also sometimes called a direct short to ground. Sparks could result and eventually the component(s) go up in smoke and is ‘fried’. If you are using your bare hands and you are sweating you become a very good conductor or ground yourself.
Now there are test equipment used to detect unwanted ground. In electric motors and other circuits, before an unwanted ground get to point where a large amount of electrical current start to flow to the casings, a test could be done using a tester called Meggers or MegaOhm meters. This tester generates a certain amount of voltage that is applied to the wires or circuits and it tests for the breakdown of insulation or insulators covering the wires. Moisture in circuits can cause unwanted flow of current to casings or unwanted ground as well. This could happen to equipment exposed to rain or high humidity or moisture in the air.
Available and cheapest at Amazon.com. The Fluke brand is the best and widely used tester in the world. The United States Navy uses this tester.
The Difference Between Unwanted Ground And Short Circuit
Unwanted grounds and short circuits are related but not the same. Both involve a certain amount of unwanted current being drawn. A short circuit is more of a direct contact between two hot wires at different potentials, a hot and neutral or grounded metal or casing. While on the other hand an unwanted ground is more of a partial contact between hot wires at different potentials and to ground through insulation breakdown, moisture or water presence in the circuit etc. An unwanted ground normally starts with a trickle of current flow to ground and could build up into a large amount which will then result in burning electrical wire and other components if the circuit breakers do not trip the faulty system in time.
Electricity And Water Do Not Mix !
Electricity when exposed to water or moisture will result in a very destructive event. Folks could also get electrocuted. During snowstorms or rainstorms, electrical current could flow from live wires down to the ground through flowing water. Stay out of the water that has built up around your homes, streets. Fallen wires could still be live and could kill you. I remember one incident where a young man decided to cut a thin but tall tree during a rainstorm. He got electrocuted when the tree fell on a hot high tension wire and the rain water was flowing on the tree down to where he was.
Knowledge And Common Sense
If you are going to work around electricity, get the knowledge including safety. This will save your’s and other people’s lives. Common sense when added to acquired safety knowledge result in a safer condition for yourself and others. Remember, it takes but a very small amount of electrical current to electrocute a human being. It takes a minimum 0.1 ampere to kill a person.
Now for some of you who want to have more capability to test electrical equipment, below is a great multi-meter kit. Available and cheapest at Amazon.com, the Fluke brand is the world’s favorite and top seller.
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