This man is fabulous he makes it so easy to understand and learning from JW is a joy

I'm a late learning doing my level two and I always come to you if other channel's over complicate these video. Thank you, I also love your calm approach to teaching

Thank you for the informative video John. I’m a electrician with mainly on site experience. I’m moving into the testing side of the field so your tutorial is great for refreshing the memory from my apprentice days. It’s amazing the depth of knowledge involved for the job and it’s easy to forget it over time if you don’t practice it. I’ll be watching more of your videos. Thanks again.

This is awesome. Very easy and instructive video with good "common issues" tips. Thanks John!

Just wanted to say thank you for making all these helpful videos. I am a beginner and you're helping me a great deal!

" you'll certainly feel it" said with such aplomb. Thank you for these videos, much appreciated.

Thank you John Ward, this was the most informative video I have seen regarding the insulation testing, keep up the good work.

John thank youfor the excellent videos.You are a great electric teacher.Electricity flows in you

what plain simple explanation well done JW and thanks for the tips on what to look out for!

Faulty defrost elements in refrigerator, another culprit I have identified. Thanks for the tutorial.

Great video John. Very clearly explained and informative. Thank you for making this video.👍

Excellent video John Keep up the good work

Thank you John, I very much appreciate your videos.

Great video John. Thank you.

Many thanks for the video. Very detailed as usual.

Love JW, and his very dry sense of humour. Makes me laugh, but I learn a ton at the same time.

Very informative .well described and put simply with diagrams Glad I found JW u tube videos.

Once when I was working as a Kitchen Porter for a major restaurant chain, I caught our 3 element, 10kW immersion heater JUST as it was starting to catch fire, due to an arc forming across insulation breaking down on one of the connectors. The smell of burning plastic when I went to get the vacuum cleaner gave it away. This lead to a very frantic 30 seconds as I turned off every single switch I could find in the cupboard, then opened up the breaker box and tried to find what exactly they had labelled the heater elements as. Definitely one of the more stressful short events of my life!

Insulation resistance testing during electrical installation condition reporting is the biggest ball ache in an electrician's existence!! There's always that one thing left plugged in or light fitting with a transformer that the customer always forgets to mention.

Candid explanation JW, keep up the good work

Very good instructions, you should teach if you don’t already. Another thing to look out for since this video was made is USB/WiFi socket outlets.

Hi John another great video thanks. My opinion on IR; IR is arguably the most important test that is ironically rarely done by Electricians. It's the test that tells you if a cable is melting and if a building is likely to burn to the ground. A good Manager will know if his FWT Engineers are or aren't doing IR Tests based on two things. 1-Are all the test results the same on every EICR/EIC/Minor Works he does? >999 ??? 2-How often do they buy new batteries for their MFT ? IR dramatically reduces battery life. Though maybe your firm has the new Megger 1730 or above which doesn't require batteries. I'd add a few other points; 1-Remember to switch two-way and intermediate lighting circuits etc all directions re-testing each time so you check all parts of the circuit. 2-Warn other tradesmen nearby to get away from extraneous conductive parts. Seen a plumber leaning on a radiator beside the mains getting a zap during IR Testing one time but it's ok he was a Plumber... 3-You never covered the 3 phase process of IR testing. 4-You may have to discharge some circuits you have put 500v through if you need to test Continuity after IR. Testing process is not always done by the BS7671 process. Leave the probes on or touch the cables to Earth Bar and watch them spark. 5-Old VIR Cables should be tested at 250V

The best and most well explained videos on the internet, you my friend are priceless!! 👍

Also worth mentioning, when testing lighting with 2 or more way switching, L-N and L-E tests need doing for each of the different switch combinations in turn. This is most fun when working alone with the board in the cellar and the landing light switches in the hallway and at either end of the landing. An increasingly common permanent load L-N would be a 13A socket with integrated USB power supply

What a great video. Thanks for the detailed explanation.

Hi John, could you do a video about testing insulation on things like kettles and immersion heater when disconnected from the mains, and cooker rings etc, from Fred in Essex.

Excellent video. Many thanks.

That's incredibly helpful, thank you

Superb explanation sir.

John,could you possibly do a video covering global IR testing on split boards? Seen other videos where only RCD is the mains switch,doesn't really help if its a 16th or 17th split board!

super explanatory video .Thanks

Brilliant thanks John. I am pretty sure if you are my teacher in electrical I gonna be the best electrician in 🇬🇧.

Great info John, thank you.

great work mr John

Sir, how would you test GFCI breaker circuit which trips intermittently even with the hot tub is totally disconnected but the wires are still connected to GFCI. Should I disconnect piggy back white wire to not to damage it or disconnect all the wires? Also should I disconnect wires from the breaker in house breaker box for maximum separation or it is enough to turn breaker off. Great presentation, thanks

your voice kicks that interest whenever i start your video, great voice sir.

I like youre explanation. This video can be only 1/3 long, but probably everybody will understant all, but remeber probably only few things. If video will be longer, nobody vew to the end. Very nice explained and right long video to remeber everything. Thanks.

Very helpful. Thank you.

great Video and tutorials

love your work. thank you alot mate helping me get my head clear on testing procedures how to and why. side note, bbc news at 10 called they want their voice back. haha

Dude your like the Maverick of electrics. Top Gunnn baby

Hi john all those items that you listed, immersions, pond pumps etc wouldn't these be isolated before the test, therefore not part of the readings?

Brilliant. Great tutor.

great videos, thanks

Another item which you may forget about when testing may include mechanical ventilation systems often found in newer homes, often wired directly in and situated in the loft. Could a separate net filter mar your measurements? The capacitors in them have an impedance which gets lower as the frequency increases, but they have a fairly high impedance for 50Hz, this impedance may be around 5 MΩ. However, the resistance for a DC current is very high or infinitive, when the capacitor isn't exposed to a voltage too high. When you use a 500v test voltage on a filter which contains capacitors rated for 400v it may cause problems?, could the capacitor insulation fail? I ask this because after disconnecting all known users I could still measure a potential between the earth leads in my consumer box and the disconnected earth lead to the earth electrode. (No metal parts should be touched in the house when earth is disconnected with the power switched on, there is no earth protection and touching a metal surface can be lethal if an earth fault should occur! I made sure no other people or pets were in the house when doing this measurement) It turned out to be the lighting in the bathroom cupboard/mirror which is directly wired in, it contains LED lights and a switched power supply, the lights are switched on and off in the low voltage circuit and the power supply stays energized all the time.

I could listen this for hours...

Total voltage DC 250,500,1000 in Megger multimeter no more option to set in DC. How can I adjust it AC ? Or DC mean throwing DC 250,500 or 1000v?

This was very helpful for me to find a short the other day. Thanks!

Hi john, just to pick your brain really, I use an analog mega tester all the time, its my goto fault finding tool of choice. Quite offer when checking an older property with damp issues, the needle on the tester will do a FSD then slowly sink back to >1Mohm (hopefully more). Would this be because the damp short is getting dried out by the 500v or maybe the initial surge from the mega is producing the FSD? Like the video presenter voice BTW! And how about a short video on analysis of analog mega readings for us older sparks?

Awesome thanks

Hi John, did you ever make a video doing SELV & PELV testing please?

Can you please do a video on breaker before SPD, because it needs to be of special kind, thank you

Example I just completed a months training for city and guilds domestic installer including 18th edition. Contacted niceic they asked have you worked in the industry for 2 years I said no (honest answer) then you cannot join for 2 years. I asked where it said this on there website? Buried on page 12 of brochure. But when you click on there join us link on the site it says quite boldly join us within 3 weeks. No mention of 2 years experience. I rephoned and said I have 2 years experience (no evidence requested) was told I could arrange an assesment immediately no mention of 2 years experience required. When they discovered it was me call was diverted to a higher up who then refused to proceed. When I asked what 2 years experience was they could not tell me. When I pushed them it could be as simple as 4 items of work done over the 2 years. Judge for yourself. Is that rectum protectum. Or raising the standards In The industry?

on light switches, understand the need for leaving switches on, but what is the procedure for two way and intermediate switches.

I found this very useful, thanks John.

im back here again. because i need refresher. Trust me, this gentlemanyl... Mr John Ward is good. Why need refresher? My bad, my age and memory.

Very helpful 🙏

Literally amazing

One of my college friends used to attach the megger croc clips to his tongue, then wind the hand cranked megger till he was shaking... I remembered him doing this when we were waiting to go into class lol....

I'm still waiting for you to play that piano...lol great training videos...

Hi John can you do a video on how contactors work, why they are used and where would we use them please, great videos very informative John

Hi John. In case one is testing a ring circuit, shall one link both L cables (incoming and outgoing) together and test them against N cables linked together?

Noticed for water culprits that electrical showers weren't mentioned. I've had a problem before where an electrical shower was tripping the whole upstairs socket circuit. Just thought I'd add that in case anyone is having a similar issue.

with regards to neons in plugs or FCUs. What is the appropriate action? disconnect them? link L-N and test across them the CPC? the OSG just says disconnect dimmers but no guide on neon devices

I install a lot of MICC and can always get an IR greater than 499 M Ohm. The worst I have come across was about 30 years ago in the houses of parliament, most of the MICC was less than 0.2 M Ohm (a lot of the pots had no RMX compound whatsoever) and most of the protection was 3036 and BS88

legend John Ward! up ya biya!!!!! man of the year so far👍

Thank you 👍🙏🙏

My meter has an additional Mohm setting of 20,200 or 200 and continuity on it has 20,200 and 2000 ohm setting. Which setting do I need for each test respectively? Any help appreciated, testing exam tomorrow and unsure, and find info anywhere and been ages since used as been on install, any help greatly appreciated.

On the IR testyou said that you could link the L & N to one prove and the cpc to the other if its impractical to remove something that could be damaged. Would that work for doing IR tests on sockets that have the USB slots on them? as I assume they would be fried with 500v

Sir why technician required neutral or graunding earthing difference demand 0.5volt.Pls sir make a video and explain with example

Brilliant 👍

An apprentice accidently meggered (500V) through the analogue supply authority kWh meter. Everything is working ok, but can the meter be damaged by doing an IR test on the submains with the meter in circuit?

Always a Joy listening to you John. Thank you!

So if you didn’t disconnect the neutral we’d get a reading between neutral and earth?

John what about dimmer switches, do we omit bypass or what

great stuff

Would it make sense to test at 250V first before 500V, that way anything that is still Connected won't be damaged

It's only continuity you need to remove lamps as it affects the resistance reading not insulation resistance as you just test between the bars and breakers on the board

I can understand how can you test between live and neutral because what goes out on the live comes back on the neutral but how are you testing between live and earth because the earth isnt connected to anything at the other end of the circuit except in a fault condition

John, what about LED down lights as it’s impractical to go round and remove them especially if there are a lot of them? Your thoughts?

Hi john great video, wouldn't it be much safer (and quicker) just to test everything LN to cpc on 250V all the time? This would negate all problems that currently exist with real world IR testing i'd love to hear your thoughts on this.

Hi John, I wonder what test can be practically done for EITR on a commercial job where you cant turn off any circuit or the whole system. THANKS

Great Videos. Thank you. Lamps: Fly in the ointment is that modern LED lamps have integrated bulbs so not easy to disconnect unless one removes the whole fitting for the ceiling.

Regarding the Guard terminal on an insulation resistance tester: when is it appropriate to use this lead? The Megger MIT525 manual suggests using it for resistances above 100GOhm but another Megger webpage says 100MOhm. (uk.megger.com/electrical-tester/april-2019/the-importance-of-the-guard-terminal-in-insulation). I don't own a Megger but I've got a cheap SZBJ BM500A insulation resistance tester that has a "G" terminal but says little about using it. The BM500A only measures to approx 1GOhm yet it has a G terminal, so I'm guessing it's 100MOhm and not 100GOhm. I haven't yet found a KZfaq video that shows how to use the "G" terminal.

Would you be able to explain the best way to test both individual circuits and the whole installation where there are ONLY single pole RCBOs (neutral fly-lead, no earth fly-lead) installed where the manufacturers instructions state that "all connections to the device must be removed prior to conducting insulation resistance tests".

Neon's within Switchgear, Fluorescent Battens (Ballasts Leakage to Earth)

John I heard you say greater than 1megohm is acceptable but isn't it correct that on a new installation you need a minimum of 20megohms to be acceptable? Great videos by the way!

Are you saying that shortening L and N for testing rings with power sockets that has USB ports integrated shouldn't damage them? Thanks.

Do you have to disconnect the neutral ? when testing between Line. Would it just give a slightly lower reading that would still pass anyway ? Please clarify

how would you test fluorescent lighting and recessed spotlights where you may have multiple lights in a kitchen ceiling or a long run of light fittings in a corridor.would connecting L-N be the method to use, with all light switches turned on

Hello John. Been a while since you posted this but I have a question if you don't mind. Take a look at the first schematic in this link. "The megohmmeter". It shows one lead of the test equipment connected to the copper core of a cable and the other lead connected to the actual cable insulation. When I first saw this I thought: Ok, you're looking to see if there is some kind of current flow through the insulation material. Makes sense right? If there is a current flow then you will notice that in the form of a low resistance across the insualtion material. So, you are actually testing the integrity of the insulation material itself. Then I look at yours and other videos on the subject of insulation testing and they show both leads being conneced to the cable core. Even though the same principles apply as far as testing the integrity of the insulation this first method uses a different approach. Do you have any thoughts on the first approach? When would it be appropriate to take that route for example? When you can't get to the other end of the cable perhaps? Cheers www.ecmweb.com/test-amp-measurement/understanding-insulation-resistance-testing

can a long length of cable, or coiled cable, induct a potentially lethal amount of power to its other conductors or fool the insulaton tester?

Don't forget shower pumps and showers. Had a Salamander pump only 18 months old tripping an RCD because it was internally leaking. Had a problem claiming it was still in warranty. Salamander registration sucks. As usual one RCD covering 6 circuits including all the lights :(

can you explain the non damage by linking L & N test to earth (9:44) thank you

Show us the megger!

John Ward thanks.

I'm following ur lessons really nice , how can I get the book

I understand 500v across L-N can damage connected loads and give inaccurate results. But how does testing between L-E or N-E cause damage? If there is no potential difference across the loads? If it does would 250v test still give you an appropriate readings and cause no damage? Only an apprentice so asking because this seems to be a great tool for fault finding and sometimes the fault is with the equipment itself.

What shall be the minimum resistance when we apply 500v.do answer plz.

There is so many items connected to mains these days and with 500v ,a lot of quick popping can occur. Always best to double check, better safe than sorry.