Appliance Protection Classes 0, I, II, III
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- čas přidán 27. 07. 2024
- Protection classes as defined in BS EN 61140, with Class I and Class II (double insulated) being the most common.
Covers all four classes, the protection methods for each one, and considerations when connecting equipment to a fixed wiring installation.
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Being an electrician I love all of your videos you remind me of my collage days at Kingston college electrical engineering department 87-91
Many thanks J.W for all your hard work....
But do you ever question what you're being told is actually correct ?
An electrician studying electrical engineering for four years?
“Whole lot goes up in a ball of flaming wreckage”. Another classic JW line :) keep up the good work.
That had me in stitches 😂
Great video. Thank you for covering all the classes and providing examples. I didn't realise how kettle elements were configured as a Class 1 device.
Assume nothing.
The best explanation I have found on protection classes. Thanks sir!
Hi Sir. Thanks so much for the clarity of your explanations. I'd been banging my head against a wall until I saw this.
Genuinely, thank you.
Jeff
Very clear explanation & advice, thanks again J.W.
Surprisingly I've come across a few examples of class 0 appliances still in use. Usually old table lamps, with either twisted or figure of 8 flex, passing through metallic parts to the lampholder (often brass). They're becoming increasingly uncommon, being at least 50 years old now, but do still turn up.
Fairy lights were a rare exception, being permitted to have only basic insulation right up until '89.
In Finland class 0 used to be the norm on things like TVs until the mid 70 and in lamps it was used longer. They now are largely obsolete as their plugs do not fit grounded sockets which now are mandatory. It was seen that class 0 is not safe anywhere where ground potential is nearby. Not that people did not pick a knife and cut the plugs in the past.
I think all your videos are excellent - very informative.
Equipment classes.
For when you need to learn about equipment. JW is our lecturer in class.
Pure class JW 👍
Great technical information as always. Thanks
Old electric clocks, which I believe have been featured before in your videos, would, if I'm understanding correctly, be something still relatively easily accessible (antiques stores and whatnot) that are Class 0. They normally rely on the insulation in the main coil to provide protection, with the movements typically made of metal, and metal components accessible from the back, and front, often, and don't usually include an earth connection.
All the ones I''ve got I added a protective earth too, just to be on the safe side.
Such a helpful channel! Thank you!
Thank you for very clear explanation.
Very good John thanks for the video had no idea class 0 even existed 👍
In Finland class 0 was the norm in dry room equipment until the 70s. In lamps class 0 was sold until the 90s. The problem is that they do not fit into grounded sockets which are in all new homes. It would be very dangerous to have class equipment in any room that has ground potential like grounded equipment. The problem was most acute in the 70s. Almost everyone did some illegal trick to fit for example their TV to a grounded socket. People either cut the plug or made an illegal extension cord.
Also if yo use class I on an ungrounded socket it acts as class 0. An example of an illegally modified class 0 plug:
3.bp.blogspot.com/-5r8ISaXrPTY/WhFmIIM3WTI/AAAAAAAANp8/kbOs6HlQoDAsIV6OkyKwQsMHAzfeakJ2gCLcBGAs/w1200-h630-p-k-no-nu/pistotulpat.JPG
I still have these ones. I even have one older ones which were originally designed for 120V, and come with only textile insulation. :)
Great video john.
Good vid as usual JW 👌
Great video, very interesting. Thanks
thanks, that was very helpfull, clear and informative.
thank you so much. I finally understand it easily
Quality content. I love it. ⚡😺
Sidebar: When I was a teen, playing bass in a band, our organ player would strip the foil from a nearby cigarette packet, wrap it around the blown amplifier HT fuse and turn it on again.
*Shudder*
That's not that bad. Most people that bypass fuses do it with a nail or a coin that most certainly will not burn out if shorted. At least the foil would have went before any of the wiring melted. At worst the foil would set alight and be a fire hazard, but much worse can happen because most people bypass the fuse with a conductor that's stronger than the internal wiring.
I take it the original fuse would take 11.
Thanks John
Brilliant video
Hi JW, you explain things very well. could you make a video explaining how to Calculate Ipf in a circuit?
Hi John Happy New year to you hope you had a great Christmas and Newyear This must be the first video for 2021
Another great video thank as always
Thank you look forward to seeing a lot more. The class 0 ie the old type Christmas tree lights the number of times I have seen people with three or four sets of them on one 13A plug then wonder why they have cort fire
Class 0 items are still being sold certainly in 2020. We purchased a string of LED Christmas lights. Inside the mystery black box was just a bridge of diodes. The wire is only single insulation. You will still get a shock to ground should you make contact with live. This was sold by Dunhelm.
YES! First post! Anyhow, great video John, as per usual.
You can get Class 2 items that do have an earth connection where it is required for correct operation - e.g. a ground plane to allow a flourescent tube to start or for EMC compliance purposes. These earth connections are not classed as protective and will have the relavant insulation (double or reinforced) to any other conductor
Now I'm aware of these 'classes', I do not recognise them. If something has a connection to mains power and has exposed bare metal, I will earth it.
And, by 'exposed', I mean can be touched by a person with pointy tools.
@@millomweb You're exactly the kind of person that shouldn't have anything to do with electricity. You saw the video, you didn't understand what was being said, and you follow your own agenda. Forget the rules, you know best.
@@fluxington Which is why I've decided anyone with qualifications don't continue inside my house. In here, I'll examine their work and make adjustments accordingly.
@@millomweb Because you know best. And your qualifications are?
Very well explained.
John another detailed pat testing video on a cheapo online light fitting elaborating the maintenance of class ratings would be great. And maybe showing how some installation approaches as you suggested can remove the class two rating.
I'm not with John. I like stuff well and truly earthed if it has any exposed bare metal parts. I've been like that since finding 240V on a TV aerial connection. I 'found' that voltage while connecting the aerial lead to the TV in the dark and spotting the spark.
@@millomweb John clearly talks about the dangers of having no earth on a class I device, and then explains the dangers of earthing (unnecessary on class II devices) providing a path for fatal fault current if someone is already in contact with another faulty device. This applies to *anything* that's earthed, including taps, sinks, etc, meaning earthing can be a double edged sword. You're talking about coax being live with no evidence of why it was that way, and what that has to do with classes of equipment.
@@fluxington I understand the issue of a good earth being a risk but it's only a risk with other badly wired equipment. It's unfair to put any blame on earthed equipment for a fault on unearthed equipment. All being well, the both are connected and the earthed will then protect both.
Class II I take as 'double-insulated' - and there are many of those that are not double insulated. The badge gets put on erroneously.
I don't think old tellies with 2 core wire were even labelled as double insulated - so no lies there !
It was the coax connector on the back of the TV that was live-ish.
More recently (early 1990s) I had a belt off a CRT computer monitor - it was completely assembled and the parts of it I was touching was the glass front of the tube and the plastic casing above the tube ! So I was touching two insulators ! (Cleaning the screen and supporting the unit with the other hand.
@@millomweb No-one is 'blaming' earthed equipment.
Do these classes also apply to secondary voltages?
So assuming you have some kind of 12V wall adapter and inside the device it's being converted to a voltage higher than 120Vdc? (Which is also isolated from mains)
Bet that speaker on the shelf behind you John pumps out some real high power tunes when you finish your videos?
Eltax Studio Pro 350s, 250W RMS continuous, from an EP500 amplifier (2x250W RMS).
Speakers were £40 from a local auction years ago.
Useful 👍
A model of clarity John. More on EV installs please.
Check out JW in his street wear ...All down wiv da kidz
This is not the first time we have seen JW in "sport" gear. Every time this happens I cannot help but think of him as a match official (referee / line man) in some junior league soccer or rugby fixture - I suspect more soccer or hockey due to the branding though.
Somehow I can see him sprinting about in the game, peeping the whistle then immediately somehow revealing the complete "Rules Of The Game" from his chest pocket, ring bound, in laminate form, flipping to laminate 1488b to explain how Rule 3437a as Amended by 2021C19 Rule 3437C has been egregiously breached and a penalty spot sanction in required.
Who would argue?
You should see him when he gets into the long game cricket season - no-one knew a 3 day game could last 10 years, yet it did as a discussion was required after every ball.
Please do not change JW, you serve a vital QA role to the industry. Besides, I like your dry humour :D
It's not everybody who can appear on CZcams displaying their organ in all its glory....
Don’t be mean about him. He’s working as a PE teacher in a school..... lol.
Class III - didn't realise the upper range of permitted voltages were quite so high. Where I work we used to have 50V DC battery supplies with open frame distribution busbars - they certainly gave you a nip, not sure I fancy 120V DC.
I was thinking 120v DC (with no current limiting) could get pretty nasty, I always thought that DC shocks were more dangerous as its more difficult to let go
@@mistermartin82 Opposite is the case, its the AC that makes it impossible to let go.
@@arcadia1701e I thought that with DC you got one string muscle reaction (to grip) but with AC it’s grip,release,grip,release with the line frequency
I used to work in a BT Telex exchange where we had 50V DC for the group selectors and plus and minus 80V DC for signalling. I couldn't feel 50 or 80 volts but would certainly get quite a bite from 160V. The signalling was later change to SCVF, voice frequency tones.
@@clivebrooks8207 Some of my colleagues couldn't feel 50V but I used to hate getting across it. We also had 17Hz ring generators, about 80V - didn't like those either!
Kettle winner :) How do you test a modern kettle?
Some Class 3 devices like Laptop PCs using an external PSU can read 230 V to Earth on the DC side of the PC input plug. Switch mode power supplys are not always isolated from the mains. Try it with your meter.
Some are faulty. Plug on mine is earthed - so the laptop is earthed - that makes me happy.
@@millomweb Check that with your meter!
@@johndododoe1411 Congratulations, it's only taken you 7 months to work out how I did it !
@@millomweb The mains plug does no necessarily earth the actual laptop.
After watching this video i checked the bum hole widening price of bs en 61140. £130 for about 30 odd pages of bumf on a pdf.
Hi John, good video!
Just wanted to add something,
You would no doubt be aware that dimmers and the like are not considered as effective isolation!
this is due to the fact that electronic components such as Triacs can fail and invariably tend to fail short circuit style, light permanently on!
a similar thinking should be applied to any low voltage equipment
With regards to class III,
I say this because I have seen a situation where small low voltage power supply used a capacitor dropper circuit to attain the low voltage directly from the mains with no isolation and the +5 on the output registered mains when measured between earth!
Therefore low voltage power supplies should have some sort of galvanic or similar separation!
Most all other types can represent a real hazard
It's done for cheapness with no regard for safety!
Kind regards Warren
I've had a conventional lights switch fail permanently on. Currently that bulb holder has a duff bulb in it to keep the spiders out.
Those components intentionally connect through mains during normal operation and cannot form the safety isolation for class III/SELV. Legitimate adapters include something else to do that, usually a tiny high frequency transformer.
And, I wonder, how many people have single-insulated wires running through unearthed metal conduit ?
I think I have a class zero power supply for old ATA HDDs and ATA DVD R-Ws , used these before I got a more up to date USB dock for more modern SATA stuff.
Glad you got sorted for the Sata stuff.
Where would you ordinarily find the protection class number on an appliance. I have just examined my Laptop PC and its adapter and can find nothing. Also, on the subject of the PC adapter, what about the 240v power lead that i can disconnect from it? The PC should be class 3 but not the adapter surely?
Hi John. Is there any risk In placing a class I and class II together? I tried searching the code but it doesn’t seem to mention on this.
It always amazes me that Class 0 still seems to be the standard for appliance cables in the US.
Mandated safety seems to diminish inversely to voltage. In the US its a rite of passage for a kid to shock their hand while plugging something in and learning firsthand what 120V feels like. I'm sure we'd be a lot less casual if it hurt twice as much than the brief "ow" we get. I know the shock and fire hazard aspects are unrelated but I feel like Europe's better insulation regime stems from their desire to really *not* want to touch a live wire. If I went to a friends house and was getting tingles from their washing machine chassis, it would probably be a 15 second conversation at most ("oh this baby's got some lose wires to look at") but in Europe you'd probably shut power off to the whole building and wait for a sparky to arrive.
Now try touching EARTH when doing that!
@@NillKitty Nah we'd forcefully unplug the device, not the house. After all, we need the ADSL modem and computer to still have power as we search for a sparky or replacement machine.
Hi John,
You say buy from reputable suppliers but I find low voltage adapters supplied with almost everything these days are a nightmare. They are often not marked with a class at all and may have an earth attached which may or may not be led through to the ground side of the dc output. If you investigate the definition of touchable conductive parts, the outer of a barrel jack can fall within the scope making this a class I device. Often the earth is intended as a "functional" earth used for esd compliance but how would you know? Also even if the device is marked class II if it has an earth connected and it is passed to the output this might mean it cannot be treated as class II and the attached appliance may also become class I even though it has no mains connection. I have seen appliances from very major manufacturers that have a metal casing connected to a separate earth pin brought through from the dc power supply specifically to earth the casing. Your thoughts would be greatly appreciated.
My laptop IS earthed.
If they were marked, it would be in Chinese!
After do pat testing what do u give out to customers
Are electric showers double insulated and 2nd, how would you suggest earthing/ protecting ac appliances on on a yacht? Thank you.
No, they are class I and therefore must have an earth connection. The metal parts are the outer casing of the heating element and in some showers the water and element are inside a metal can.
Earthing on a yacht is the same principles as anywhere else, the earth connection is at the energy source which would be a generator or inverter. However such installations are not covered by BS7671.
what about max V we can use double instantiation equipment
A Class I kettle fails earth continuity the first time, but passes when you move the test clip, to a cleaner part of the element. Should I fail the appliance?
I know you say earthing a class 2 device creates more danger, but how is this more dangerous than earthing a class 1 device in terms of providing a route to earth? Specifically I’m talking about metal light fitting. I’ve cut the DI connectors off as they were too fiddly, connecting ceiling rose wiring via wagos, and on someone else’s advice earthed the mounting bracket, to make it “class 1”. Is this unsafe? The problem I have are inaccessible ceiling voids and rigid insulation.
I have an IKEA desk lamp which is class III. Also my Christmas lights (which I am leaving up as I haven't had a proper Christmas) are marked class III despite being purely battery powered.
All battery powered appliances are technically class III
@@cezarcatalin1406 Yes but few are marked.
The IKEA desk lamp is mains but with a transformer. The transformer is class II, the rest class III.
@@cezarcatalin1406 Does Class III even apply to battery stuff? After all it is a completely separate "installation" (at least if the batteries are normal AAs or similar).
It does correctly apply to the IKEA lamp - the plug/adapter is class II, the rest is class III (and metal!). This particular lamp appears to need 4 volts DC.
I also have a Tesco table lamp which is metal but class II, it's metal so you can touch it to change the level of dimming. (It provides three levels.)
@@seprishere the class is based on the construction of the electricity using appliance... batteries provide electricity hence
SELV (Safety Extra Low Voltage) is used down here in Australia and New Zealand for things like fans and some types of light fittings that are in installed in bathrooms and toilet rooms.
ELV over here is defined as less than 50VAC and less than 32VDC, so a lot of these things run on either 12 or 24V.
One aspect of these things I don't particularly agree with, is that you have one of them nasty "wall-wart" plugs, plugged into a socket-outlet in your ceiling void, to power this equipment, where it gets really hot during the summer, they are all made out of black plastic, they have been known to start the odd roof fire.
What voltage are the output wires relative to ?
Let's say the voltage across the wires is 12V What is the voltage on one wire to Earth ? Usually they're not connected - so could be anything - like 240V. So you could have one wire at 240V and the other at 252V and you still have your 12V supply - and either wire could kill you.
I think you for those backwards. It would make no sense to have lower limit for DC. In Finland it is 50 VAC and 120 VDC.
There are two probable"Class 0" products that I've recently come across in UK.
First is smart-home WiFi switch beloved of the " middle tier" of geek for smart-home items. These contain a mains power PCB enclosed directly in a single skin plastic housing, no CPC. Popular brand in that regard is 'Sonoff".
The other product is 230V LED rope- light for gardens. These are modern equivalent to old Xmas lights. Led's are organized such that enough in series plus the current limiting resistor makes up 230V at the user-cut lengths, typically 2 metre. AFAICT, it's in a single layer plastic clear sausage. The user chops it off, pushes in a dodgy wire pin thing to connect the mains tails to the internal conductors, and installs them in their garden etc. One outlet of this is AFAICT a " LED ropelight" from a seller called Mr Resistor. I believe they also do a genuine neon version called 'filament ropelight". ( Both may carry the "neon" moniker from some sellers, which may be incorrect in the case of the LED version).
Surely those Sonoff devices are meant to be installed in an enclosure?
@@Grizzly01 Well I would, but not so from on-like geeky youtubers or manufacturers original intent. Saying that, I just went to their website before answering here and it seems they have re-vamped their basic model, and it now bears a double insulated logo, Probably an improvement over the first models then.
Class 0 Christmas lights - yep, still going strong ;)
@@voltare2amstereo Just for those or for everything ?
We have 1 'RCCB' which we can plug in anywhere ;)
5:23 So what class is it where you have exposed live parts inside a metal case that's not earthed - like a Sony EVS800 for example ?
10 p in the right ventilation slot should complete the live connection to the unearthed casing.
I'm not sure I rewired both of mine with 3 core cable, but I certainly did one as well as a Panasonic video mixer with exposed metal parts. Which interesting was internally fitted with a marked terminal on the PCB for earthing but fitted with a 2 core cable.
Items like that, if they bear the class II construction mark, will be using the layer of air inside as insulation, which is only applicable if the case is intact.
The standard allows for it, but it does smack of a cost saving measure.
@@Grizzly01 'case is intact' - yeah, but holey ! With a freshly sharpened coat hanger, you could make contact with live terminals with case in place.
I have similar thoughts about (belt) guards with holes or gaps in hidden places that are big enough to get a finger through and in danger.
@@millomweb Definitely need to read up on IP ratings. First digit deals with these dangers.
"No one makes these any more"
> 100% of American x-mas lights exactly as described here.
We switched to LED's because $$ but still using the same single insulated full-voltage lead in series with all of the asscoiated problems.
Ironically these are the only thing most people own in the US that has a fused plug.
Mine are labelled class 3, and quite expensive to run, running off AA batteries.
Don't know if running those LED lights through an isolating transformer would be any safer. 110v equipment on building sites are run through an isolating transformer which has a centre tapped secondary winding. This centre tap is connected to ground/earth. This will necessarily make the use of double pole breaker as an overcurrent protective device on the transformer's output.
I may have ruined a lovely mains table lamp! This eBay lamp, shallow round metal base, narrow chromed metal upright teeing out to ceramic led sockets was not earthed. But all through was run in its own sheath and an extra silicone sheath. I thought it had to be earthed but it looks like you are saying it could still be Class II, is that so?
Silicone sheath would be the second insulation.
I’d be interested to hear your thoughts on the code of practice v5 for inspection & testing (Pat). I hear so much conflicting information from various people so it would be good to hear it from someone who knows what they’re talking about.
What are they conflicting about🤔
I'm a sparks and a PAT testers
Feel free to ask me. I'm intelligent.
Talking about the kitchen hood, when you connect cpc to the metal enclosure and fault happens on the other device... . Because of the continuity of cpc both hands will become 230 and no current will pass.
True, but only if you are not in contact with anything else such as the floor, wall or whatever.
@@jwflame In recent years, based on the regs , rebars inside the concrete should be connected to main earth terminal which solves this problem for new buildings.
How about Class Special.... ?
CRT Monitors - no Earth due to they have a virtual Earth, but they are not a Class 2. ( for PAT testing you have to do a altered Class 1 test ).
Some test and measurement equipment (non consumer).
Zero Earth areas as defined in RTEEB (CRT and HV SMPSU) repair areas.
Semi conductor prodution lines, ie Timex and Casio put 50Vdc throu the staff, ie virtual earth set to 50V not zero V ( E ground ) set at 50V to stop static,
Class 3 at 50V was beacuse of BT Engineers didn't need a IEE licence, and a BT Telco one would do.
If we use ELCB in a circuit, we need equipment earthing ? Because it will trip the relay and the circuit breaker too right ? If there is any difference in incoming and out going current / voltage in the circuit. Please explain me sir !
Class I equipment always needs an earth connection.
ELCBs are for additional protection, and can't be used as the only means of protection - if you rely on ELCB only, people will have to get a shock before the device disconnects.
@@jwflame They may not get a 'shock' but will have to pass 30mA.
ELCB is good to have on unearthed items - then if the person using the item forms a circuit between live and say a sink, the ELCB will cut the power. The person is the earth lead :)
2:11 "Installation" - a tip of the slung !
Aldi still sell this style
thank you very much I am new in the compliance field and this video helped me a lot!!!
Why are metal table / floor lamps Class II when the mains wire goes up the metal stand with only the PVC wire insulation? I can never understand that?!
The PVC insulation is most likely double layered, hence satisfying the double insulation requirements.
@@Grizzly01 I didn't think I that the standard mains flex PVC outer sleeve counted as double insulation to be honest but thanks for the info.
I have an old all-metal sewing machine that is not earthed (class 0???) Is it possible to test this?
My suggestion:
Check continuity between the motor body and sewing machine frame. If there's continuity it's not safe. Mount the motor on an wooden board and see the fasteners are not in contact with the machine frame.
Thank you for your video very helpful
Alot of USB plug chargers fail PAT just on inspection as they have no class 2 markings and class 1 test would fail as no metal. The rule is no Class 1 2 3 4 marking then regardless of what you think the class should be, you treat it as a class one and test as a class one, which more than likely will fail, due to you can not get the earth test probe on to any metal, or the metal is not earthed as it is a class two inside with a additional metal covering.
Also metal hand tools, ie old drills, hair dryers and curlers are banned ( fail a PAT automactically ) regardless if they are class 1 and pass a class 1 test.
They are lots of odd rules for class 1 2 3 4
I have also come across a class two with Earth (which can be allowed) and a HV DC with Earth which you treat as Class one.
Seaward PAT testers has special settings for these in the top models.
Again these old Classes are not consumer, but found in Manufactuering, Mining, EX areas, Medical, other test and measurement labs and even some EFTpos.
You sound like you were mistrained to be an unreasonable bastard, misapplying misunderstood rules. Because whomever trained you told you those misunderstandings.
Would a 240 watt hair dryer fit in a shaver socket ?
The saver sockets are limited to 1 A. Hair dryers take some 5 A or more.
@@okaro6595 It'd have to be a microscopic hair dryer and you'd need 2 of them to insert simultaneously ;)
Great video. Now I know what all the vlogging electricians are on about "Another class 1 without protective Conductor"...
Why have you never asked ! 😀 there’s no such thing as a stupid question
I'm intrigued by the concept of not connecting the outer shell of a class II device to electrical earth. Is this not the opposite of bonding the 'gas earth', 'water earth' and electrical earth together?
That was my thought too...it is the whole point of an equipotential zone.
Water and gas are bonded to the main earth terminal because they are already at earth potential (due to being buried in the Earth), and it's desirable to ensure that they and other conductive parts remain at the same potential when a fault occurs.
Conductive items that are not connected to anything else, have no potential and are not forming part of an enclosure for single insulated conductors are better left that way, as connecting them will make them have a certain potential, and increases the risk of shock between them and some other item.
Bonding items that have a potential or could have under fault conditions is necessary to reduce the risk of electric shock.
Things that have no potential and are properly insulated from things that could provide a potential have no risk of electric shock to start with, so bonding those makes the situation worse.
@@jwflame well done it’s an area with so much confusion.
Thanks for the reply. I have often wondered if all the metal work associated with my (manually operated) garage door should be earth bonded. Looks like I now have the answer...it shouldn't.
The outer shell is in most cases plastic so it would make no sense to connect it to the earth.
What class is an electrode boiler?
Depends on it's construction, could be class I or II. The electrodes and the water they are in would be contained within some outer vessel, which could be metal or plastic.
Its a class -1,because it intentionally make the water live and touchable.
Are the 240v led strip lights classified as class 0?
They should be class II, with 2 layers of insulation over live parts. However anything is possible when obtaining items from dubious vendors.
John Ward
Some newer expensive outdoor lights are class 2 up to the control box and class 0 from the control box onwards - BUT with the weird specification that they also include current limiting circuits and some funny differential protection in the control box itself that uses a tiny relay to stop faults to ground.
The relay is the default open type and the circuit trips it at about one milliamp DC.
Edit: the insulation is some black rubber and it seems to be thicker than what is found in indoor christmas lights. It could be all just a class 2, though I doubt they actually bothered to use double insulated wires and put double-insulation on each individual light. It’s still better than those who legally hide behind something like “it’s double-insulated cause it has a layer of plastic and a layer of air”.
It can also be''class -1''.Lower than class 0,you can touch live parts.
The power brick for my laptop has a 3 conductor mains cable connected by a sort of Kettle connector, but with a rounded body. The earth pin of the plug is connected to the "kettle plug" but there is no way of telling whether earth is connected inside the brick.
The output lead to the laptop should be earthed. I presume the brick powers the laptop via a wire rather than magnetism (contactless charging)?
@@millomweb Both the +ve and -ve on the laptop barrel jack have about 100kohms resistance to the mains earth pin, so no earth connection to the laptop.
@@MrFlint51 No resistance on the outer part of the plug on mine to mains earth.
@@MrFlint51 I got 40k resistance between Earth and a USB port on the laptop.
@@millomweb Not always.
Some brands bring the earth connection through to the dc output barrel, some don't.
For example, Dell quite often do, but HP don't, in my experience.
If cooker hoods housing may not be earthed then why do we bond the sink which isn’t even an appliance?
Sinks do not need bonding.
Hello brother can you make the ATS video with the caption........... Follow you from Iraq with a lot of thanks
Another example of Class 0:
media.springernature.com/m685/springer-static/image/art%3A10.1038%2Fs41557-018-0145-1/MediaObjects/41557_2018_145_Figa_HTML.png
😀👍
50V AC or 120V DC. I know it’s 50V AC safe but how about 120V DC?! Is it safe too?
Up to..
🙏🌹🙏
Sorry john your not quite correct, BS EN 60598 for lighting DOES allow for earth pass through on a class II device as long as the earth does not terminate or have a connection to driver/control gear - Therefore 3 core with earth wire could run into a class II luminaire and back out ! So not totally accurate to say all class II devices have no earth connection... some will have dumb terminals that just provide a loop in-loop out terminal separate as i said from driver or control gear. Also there is definition of "Functional" earth rather than "Protective" earth allowed for class II which is allowed earth connection on class II devices for EMC or screening purposes which is marked with a different symbol or "FE" and NOT relied upon for safety. Did you know also there used to be a class OI ?
none of my low voltage adapters show that class III symbol.
The adapters are class I or II, it is only after the adapter that it is class III.
What Class are Electric Toasters? They should be Class -1 as they have exposed conductors with no insulation. You can touch the live parts with your finger.
Class I. British are disadvantaged in that as the plug does not tell the class. In most other countries the plug immediately tells the class.
@@okaro6595 Ditto radiant fires.
@@okaro6595 Unless you have a moulded plug fitted to the equipment, with an ISOD rather than an earth pin. Then it's straightforward to tell the class =)
@@Grizzly01 In Finland class 0, I and II have all different plugs. Class 0 plugs fit only ungrouded sockets. It would be dangerous if yoụ touched a failed class 0 equipment and a grounded one at the same time.
I wonder what JW eats for his dinner
scAMPi and fries
Another ReVOLTing joke from me 😂
Not off a metal plate, obviously.
2:00 live conductor in class??
What??? Is this a music lesson??
How Odd. To buy BS EN 61140 from BSI costs £260. To buy DIN
Yes. These things are very expensive. One option in normal times is to go to the British Library and read it there, maybe some university and public libraries have it too.
It causes problems and pain when you mix classes.
Class 2 TV and Class 1 PC.
Made the mistake of connecting these together with a 'leading signal' phono plug.
It blew up an ic in the TV due to float voltage.
The pain?
The repair man took out the 16 pin ic put it on my carpet then later knelt on it putting a neat row of 16 bloody holes in his knee.
Despise class 2.
This is due to float voltage and ADDITIVE leakage current 'tingle'..which can actually become dangerous if you connect enough class 2 devices together.
Shouldn't be allowed.
I miss the entertaining videos. Was nice while it lasted. I'm sure plenty like the educational slant now rather than the comedy and quips.
Interesting what class would you put an electric toaster in. Without grandfather rights you would never be able to buy one today.
Live conductors that can be touched with no trouble at all fail all known standards today. It’s in a class of it’s own.
Class -1. But if someone is idiot enough to put a knif in,he deserves to get shocked.If he survives,he probably wont do it again,if he dies,its just proof that natural selection works.
@@mernok2001 Just goes to show that by its very design a toaster will not meet any EU CE safety standard in force today
@@TheEmbeddedHobbyist Those standard are for idiots.Did you hear about 'suicide'showers used in South America?Brazilians say they take 2 or 3 showers every day but never heard of anyone who got electrocuted.
@@mernok2001 Toasters cut the power on both sides when the tray is up, at least mine does.
@@okaro6595 Yes,but if someone is idiot egough,he can put a knife in it when its on.But as I said,if somefone does that,he deserves to get zapped.
I'd totally ignore JW's advice about things not being earthed. If there are any exposed metal parts on a piece of equipment connected to mains power, I'd say get it earthed. You generally find exposed metal parts on connectors for microphones, video leads audio leads etc.
My very plastic laptop is earthed - by the manufacturer of the power brick.
Then again, you may cause unforeseen problems by randomly earthing bits that have been designed not to be earthed.
Especially in audio visual equipment.
@@Grizzly01 Audio connectors do not dictate what equipment is connected and whether that provides a path to mains earth. Audio equipment connected to this laptop will be earthed whether it likes it or not.
In one of the items I earthed, I connected the earth lead to a PCB at a point marked on the board as an earth point !
Similarly, audio equipment may be connected to a live connector on other equipment - and that's precisely why I've added earthing.
A metal clad double insulated VCR connected to a TV Aerial socket at 240V is not a good situation.
@@millomweb Fucks sake, if you've got an aerial socket at 240V, you've got more to worry about than some poxy earthing on your VCR 😂😂
03:52 did JW just misuse the word "exponentially"? Disgraceful
The cascading failure may cause current to grow exponentially with time, but the curve need to be plotted and studied to determine if it's exponential or hyperbolic.
So cheap chinese LED christmas lights are class 0?_
Usually they are class -1. Too dangerous to use.
17:00 Talking outta your arse John. My laptops are earthed - I get 'mild' continuity between USB ports on 2 laptops only connected to the mains. The outer pin of the power brick plug IS earthed - so the laptop is connected to earth - so I guess it's a class I device.
It does sound like you have some knowledge of the subject, but not quite enough to know when you're talking out of your arse.
Look up Class III construction, and you'll see what it says about earthing.
And then you'll realise that your laptop isn't actually a class III appliance, as the power supply isn't SELV.
17:30 Talking bullshit - it doesn't matter if the item runs at 5 Volts or not. All that states is the pd of the connectors is 5V - so they could be 235V and 240V - they will work fine and possibly kill you.
I installed 3 LV bathroom lights for a friend. The colour codes I used for the LV wiring was brown and green/yellow. The green/yellow being earthed and the brown being 12V above that.
So, despite being LV, they were still earthed. So, even if the transformer had a complete meltdown, it would not be possible to get an electrical shock from the earthed side of the bulbs.
13:00 TOTALLY DISAGREE WITH YOU ABOUT NOT EARTHING SAY A METAL COOKER HOOD.
The reason you give is total nonsense considering most other metal surfaces in the kitchen will be connected to earth - sink and all appliances etc.
So I'd recommend connecting any bare metal to electrical earth. You know, like is recommended with heating radiators - LOL
You are getting into the realm of the difference between earthing and bonding.
There is the potential to make something more dangerous by bonding it when it doesn't need to be.
@@Grizzly01 That's why it should be earthed, not bonded !
True, connecting every metal part in building to ground is always good and the more is the better
Glad you mentioned at the end about class 2 light fittings, with the small terminal block and sleeving, which should be wired with, for example, a flex into a JB in the ceiling, rather than using connectors in the base. I've declined installing them when there's no chance of getting the JB into the ceiling (because e.g. can't cut a trap because there's fitted carpet on floor above, or the base isn't large enough to cover the size of needed hole in the ceiling below). But dread to think how some have then connected them, either at customers insistence or as take the money and run - probably, as you say, just using connectors.
A common solution is the plastic cone between ceiling and flex. These are large enough to house the connector, but are really only certified as a cosmetic cover for ugly attachments such as a rusty hook carrying the weight of the lamp through the outer sheath of the flex.
A mini junction box would be pretty handy in this situation