How to use a Megger to Identify a Faulty Component

[@siltv4103]

That's how you explain a megger testing procedure! Simple but easy to get! Learned something new again! Tysm sir!

[@raviyadav8743]

Very informative video 🙏🏻

[@eSpares]

Hi, thanks for your comment. Glad our video was useful for you!

[@QUIX4U]

2:20 NEVER EVER blind test anything with a MEGGER, until you deliberately short the two test leads and POWER it on, for at least 5 seconds, to prove to yourself, that it's internal batteries are sufficient and (still) charged correctly. Then, and only then, do your installation (&/or appliance element) test If you get a reading of "less than" 2 M ohms ? It doesn't necessarily mean the element itself is faulty, but it can show that the element either hasn't been used from new (if maybe stored in a damp environment), or has suffered immersion in water (if the user accidentally washed it). Either way it isn't absolutely faulty but should instead be powered ON for at least two hours, on your workshop test bench, away from flammable liquids &/or varnished bench tops etc, whilst the circuit has a current limiter such as a 100 watt filament globe, so that if it IS faulty and shorts out thoroughly, only the light will glow brightest. However I would expect that over the two hour period (during which time any moisture in the hydroscopic insulation material of that element, should vaporize OUT, meaning) the light will dim until it goes out completely, by which time - you can (after the full two hours) again put it on a resistance retest, where the element will again have a very high resistance, and the light bulb is still testing OK too. At that result, you will know the element is in fact in good condition, and was just "temporarily" effected by poor storage, or an accidental immersion. However, a MEGGER is only supposed to measure the entire household, or industrial/commercial properties, entire as built insulation resistance test, such as is supposed to be done in any "new electrical installation or in a recent addition", (by a registered electrician as part of continuity and insulation tests, prior to reconnection to the mains supply). It isn't supposed to be used by private (untrained) citizens as if a fool-proof resistance tester. Most MEGGER's will be powered by 12 volts from 8 AA batteries, BUT the 10,000 Volt "instantaneous spike" can and often does, kill an unwary operator, who stupidly insulation tests themselves, either by accidentally touching the probes when holding onto something they are tyring to test, or they are leaning on a metal cover, that is also connected to whatever is being tested, when holding another probe recklessly, thereby frying themselves, by stopping their hearts. ALL Electricians (who undergo several years training and mostly 3 years of "night school" theory & practice education" and who are thus taught to ALWAYS "disconnect" any such heating element appliance (as the hydroscopic elements quite often provide faulty installation tests, when there isn't any fault - just a damp element that needs to be dried out), before connection to the mains supply, hence the drying circuit MUST contain at least a 100Watt (or brighter) bulb, to avoid a direct short if the element is actually faulty. I have seen "new oven elements" test well below 1 M ohm, if they have been incorrectly stored. (such as a demonstrator, on a shop floor, in damp winter conditions), which when "correctly dried out", (before installation connection), test absolutely fine and well above 50 M Ohms.

[@gozalbeitar8762]

So simple and so useful! Thank uou!

[@eSpares]

Thanks Gozal, glad to know this video helped. Remember to like and subscribe for more helpful videos in the future.

[@riyadabdulhafeed2899]

Very helpful information. Thank you so much .

[@eSpares]

Thanks Riyad for the comments, remember to 'like’ the video if you enjoyed it or it helped.👍

[@curiousjoe395]

Is this using the Insulation Test feature on a MFT?

[@alexandrefacciondesouza7744]

Thanks for the lesson!

[@eSpares]

+Alexandre Faccion de Souza Hope it has helped, the main reason for the video is to explain that you can have a faulty element that appear OK when tested with a normal meter. That is one of the reasons why professional engineers will carry a 'Megger' when doing repairs.

[@sheffield122]

Well presented!

[@eSpares]

Thanks Rick, we hope the video also provides some usefull information for some viewers.

[@nastgawdat962]

Good information

[@eSpares]

Thanks for the comment. 😊

[@alphamototv7606]

Sir,, it's okey if i will use ohmmeter to detect if there is an short circuit?

[@riyadabdulhafeed2899]

What's the maximum testing d.c voltage selection to make insulation test of any home appliance and the minimum safe resistance by using a megger ? Tank you so much .

[@eSpares]

We believe the general rule is to apply twice the appliances AC voltage ie if the appliance is 230/240 volt the insulation test would be using a 500 volt tester. A 'good result' would show a resistance to earth of over 2 meg ohms but it may be acceptable if not lower than 1 meg ohm. This is a guide but regulations in different countries may differ.

[@raviyadav8743]

🙏🏻🙏🏻​@@eSpares

[@alanshaw7365]

When testing element you state there was "no resistance" on the new component when in fact the resistance is over 1000 meg ohms.

[@eSpares]

+Alan Shaw What we are saying is that there is infinite resistance or no measurable resistance and not Zero ohms which would be a short circuit.

[@eSpares]

:-)

[@rocketry100]

Good point - something offering "no resistance" to electricity wold be 0 ohms.

[@turtlezed]

Yeah I heard that, he got it arse first, ....

[@alexanderwagner3334]

He should have said the component has a very high-almost infinite resistance to the casing which is good-not "no resistance" which would indicate a fault to the casing

[@MrK0DE1]

Hei eSpares, if a heating element has an IR value close to 0, it will short circuit, and if immersed, can result in the death of the heating element, am I correct?

[@eSpares]

A typical water heating element will have a resistance of between 20 and 30 ohms so make sure you use the lowest resistance range on the meter or it may suggest you have a short circuit.

[@rahulsaab1615]

good information

[@eSpares]

Hi Rahul, glad you enjoyed the video.

[@harithapa763]

Thank you sir for nice video, This time selector switch which select on position 250 or 500 please

[@eSpares]

Thanks for the comments, sorry we do not understand 'This time selector switch which select on position 250 or 500 please'. If we can help further please let us know.

[@scotticusnorvegicus]

@@eSpares I think he's asking do you set the Megger for 250V or 500V.

[@eSpares]

Hi Scott, thank you for your post and the meggar is set to 500v and you can see it just before Mat tests the components.

[@asifakbal4548]

Thank you so much

[@eSpares]

You are welcome.

[@mattwigg2947]

Surely it’s not good advice to tell a non trained homeowner to obtain a device they don’t know how to use correctly that can output up to 1000v (granted minimal current) and test a heating element and put it back into circuit, one false move or re fitting incorrectly could result in damage or injury.

[@samosman1260]

I don’t know how this is related to aircraft maintenance but I’m here

[@danilodatuin6217]

why is my megger only read (fluctuating from 10 -1 meg ohms, it should read infinity. because the two leads are not touching each other.its the same megger you are using

[@eSpares]

Hi Danilo, it sounds like your Megger has a problem, possibly from damp or corrosion on the PCB in the meter. Try keeping it in a warm dry environment for a few days to see if this cures the problem. If not you will need to get it repaired. 😐

[@davefaddel6761]

Thank you, now I know :-)

[@eSpares]

Hi Dave, thank for watching and glad you found the video useful.

[@zafarhussain9223]

I could not get understand when u stated there is no resistances found in component..although meter showing 1000 Ohm....may be I could not get accent...can some body clear my doubt...

[@eSpares]

Hi Zafar, this meter is testing for insulation breakdown to find out if a component has failed if it is down to earth it will show a lower resistance meaning it is likely to blow the fuse.

[@mattwigg2947]

But you stated no resistance which would mean a dead short, whereas you had 1000 meg ohms (high resistance) the wording is misleading.

[@ianfraser2009]

Hi Mat, he is checking to see if the element is good. It would of been good to show people who are watching what a bad element reading would look like open circuit .However this is a test you would do if you are a service engineer or technician in the trade working on Dishwasher or washing machine or glasswasher. Who understand the laws of testing components in white goods or boilers or commercial Dishwashers. Have a good day and keep up the good work Espares. Have a good day .

[@yasvarusaimohideen3741]

hlo sir...how to calculate the ir value of cables

[@eSpares]

Hi Yas, you should not need this for repairing appliances, is there a appliance problem we can help with?.

[@misstakenot9582]

eSpares clearly don't supply tripods... ;)