If you own a yacht or commercial vessel it should go without saying that ensuring your electrical system is operating at peak performance is extremely important. While there are a number of tests that can be run to determine the health of an electrical system, megger testing should absolutely be a part of this arsenal. At Tess, our yacht electricians can help to accurately assess your situation. Learn more below, then contact us to schedule yacht service today.
What Is Megger Testing?
A megger test, also known as insulation resistance testing, is run on the wiring system of your yacht and helps to determine any problems in the wiring that can lead to electrical failures, fires, or shorts. To measure electrical leakage in a wire, a current is passed through the yacht’s electrical system to determine the electrical insulation level in any device such as a motor, cable, and transformer. The results of this test are measured in Mega ohm.
Megger tests work on the principle of electromagnetic attraction. When a current-carrying coil is placed in the influence of a magnetic field, it experiences a force. Torque is created through this force and is then used to deflect the point of the device that gives some reading.
What Is Megohm or Megger Testing?
A Megger test is essential because it audits the condition of the electrical system of your yacht or other commercial vessels. Also known as insulation resistance tests, Megger tests use a high resistance meter with a test voltage of about 500 volts dc.
Why Is Megger Testing Done?
Megger testing is done to verify the overall condition of the electrical insulation of a yacht or any commercial vessel. Through insulation resistance testing, you can easily determine if the insulation resistance quality of your yacht or commercial vessel has degraded due to wear and tear environment conditions and dust particles.
The information you can gather from Megger testing makes it easier for you to determine if your vessel requires repairs or is safe for use.
Efficiency Testing
Megger testing measures the efficiency of the electrical system present in a vessel and its dielectric condition at a specific moment in time. Through Megger testing, any leakage is detected and measured across the dielectric materials in the insulation.
What Makes Insulation Go Bad?
When the electrical insulation in your yacht is new, it’s expected to be in top-notch shape. However, regardless of how manufacturers thrive on creating the best wires, cables, and motors for a yacht’s electrical system, its insulation can eventually go bad because of mechanical damage, vibration, excessive heat or cold, corrosive vapors, and humidity. The more frequent the vessel is used, the more exposed it is to elements that can adversely affect its functionality and life span.
Over time, these enemies of insulation will start to damage the electrical system of your yacht, resulting in a low resistance path for leakage current.
What Is “Good” Insulation?
Every wire present in your yacht is covered with some form of electrical insulation. The wire itself is usually made from aluminum or copper — materials that are known to be good conductors of electric current that can easily power your equipment.
“Good” insulation is one that resists current and keeps the current in its path, along with the conductor.
Benefits of Megger Testing
Being able to identify any current leakages is one of the biggest benefits of conducting Megger testing. When left unresolved, these current leakages can cause damage to other electrical circuits and machinery in your yacht, preventing the vessel from functioning correctly.
What Is Done During Megger Testing?
Megger tests are beneficial to determine the health of the electrical system of your yacht or commercial vessel, but they should be done carefully. Using the wrong processes or equipment will prevent you from assessing the condition of your yacht’s electrical system and increase the likelihood of accidents.
Megger Test for Cables
A Megger test for cables is a continuity test, which means that the power to the circuit must be turned off. To conduct a Megger test for cables, you have to turn the breaker off or unplug it. Determine the connection of the cable you want to test to gain access to the exposed conductors, attach the alligator clip to one of the merger probes to the cable, and then press the test button.
The Megger will produce a current between the probes, and the meter will indicate the resistance of the jacket based on the flow of the current. You should maintain for at least 30 seconds to get a reliable reading.
Megger Test for Transformers
To conduct a Megger test for transformers, start by disconnecting all the neutral terminals and lines of the transformer. Once done, connect the Megger to the LV and HV bushing studs in order to calculate the importance of IR insulation resistance.
How Is Megger Testing Performed?
Megger tests are performed by applying a current-limited DC test voltage between the chassis of the equipment and the conductors. The test current or test voltage is placed for the industry standard of one minute to ensure that all readings made are based on the same length of time.
Types of Megger
Aside from knowing how a Megger test works, it’s also important to know the different types of Megger to use. As mentioned, knowing the right processes and using the right equipment will ensure the accuracy of your reading.
Advantages of Electronic Type Megger
The electronic type megger has a digital display, two-wire leads, selection switches, and indicators. Using this type of Megger is beneficial because the level of accuracy of its reading is high, IR value is in digital type, which means that it’s easy to read, and it can be operated by one person. An electronic type megger also works perfectly even in very congested spaces and is handy and safe to use.
Advantages of Hand Operated Megger
Some of the most important parts of a hand-operated Megger are its analog display, hand crank, and wire leads. Using this kind of Megger is also advantageous because you don’t need an external source to operate it, and it is very cheap in the market.
Megger Safety Precautions
To ensure your safety when conducting the Megger test, you should only use meggers on high-resistant measurements, such as insulation measurements, or when checking two separate conductors on cable. Moreover, you should never touch the test leads when the handle is being cranked or discharge the circuit before connecting a megger.
Safety Measures While Doing Megger Tests
When conducting a Megger test, you should use protective gear, such as safety glasses, insulation gloves, and flame-resistant clothing. Jewelry should be removed, and you should only stand on an insulation mat.
Most importantly, when connecting the test leads, you should use insulated rubber gloves.
Schedule Megger Testing In South Florida Today
If you’re interested in scheduling insulation resistance testing for your yacht or commercial vessel, contact the experienced marine electricians at Tess Electrical LLC to schedule a full yacht survey. Our team is available to assess your yacht any time of day – early mornings, late nights, and even weekends. Click here to schedule now.
