My grandparents had a very old house with an electric water heater in the bathroom. Looked like something from a Frankenstein movie. The control box had two enormous neon indicators that would glow a satanic pink and terrified me as a kid. Anyway I pulled it apart when they modernised the bathroom and the water ran through an exposed wire element. This thing had been in service for not much less than 100 years I imagine. They don’t make em like that anymore. They had a mixture of rubber cotton wiring and even some wood covered cable. Was still all in service in 2000 when the sold and moved out. They also had the remains of a generator in the cellar. All the rooms were enormous with servant bell. The whole house was really creepy

This reminds me of an experiment I did (unwittingly!) many years ago. A CT system running at 120KV with about 100mA normal current in the xray tube, suddenly overloaded and the system turned off. (With a loud bang 😀 ). No problem could be found and when switched on it operated normally. It did this once a week for a number of weeks. Each time it was reset it operated normally for days or even a week. I eventually traced it to water in the cooling oil of the xray tube. The oil was pumped into a heat exchanger which was water cooled. The cooling water then run to waste. Little holes had developed in the exchanger and eventually the oil was replaced by an oil water mix. It shows the water in Melbourne Australia is quite soft with minimal contamination!!!

I suspect the reading could be vastly different with an old pipe containing mineral deposits along the inside surface. Also water from different areas having different dissolved mineral contents. I've seen the inside of plastic pipes stained blue with copper from old copper hot water tanks. Interesting experiment all the same.

very interesting john, always wanted to this. been watching your videos for a while now. you seem to answer all of the nice to know questions !

In the power station we used demineralised water to cool the stator windings which were at a potential of 17kv! The core tubes were fed via PTFE pipes not dissimilar in appearance to the pipe in the video.

0:33 JW, strokes his solid pipe! 🤣

Very thorough experiment with all the variables accounted for. Job well done.

Interesting practical demonstration.

nice video jw , informative as usual

So the conductivity of your drinking water is about 560 uS/cm which is quite normal. Nice video it made me realize that potential equalizing is essential in modern installations because the pipe isn't conductive anymore.

Would have been interesting had you checked the pipe empty first. Some type are conductive.

This reminds me of when I moved from an area of soft water to hard water, it took a lot of getting used to, more washing powder, washing up liquid, and shampoo. The water was so hard I even had to wear a crash helmet in the shower.

Nice video John, very interesting.

Thanks John

Thanks John. I was taught that about 1 m of 15mm plastic is enough to turn exposed metal to extraneous. Given the figure of 23kohms minus 1 k ohm for dry skin you'd need slightly more than 1 m between the earthed pipe outside the bathroom & the touchable metal pipe above the floor to omit supplementary bonding with your figures. Apparently that figure doubles when you have central heating additive and doubles(approx) again for 22mm. So an "insulating insert" on the incoming water at POE under the is going to need to be approx 2.5 M to be truly insulating. Did i do my maths right or have I missed something?

Very informative demonstration thanks. This could answer something that has puzzled me where firemen poring water onto a building never seem to worry about the electrical cables inside that are live.

That's a very interesting video there John. Kind of relevant in my neck of the woods at the moment. I've been reading in the news about a young girl in Western Australia who was electrocuted after going to turn off a garden tap while standing in a puddle of water. The poor girl somehow got full mains voltage at 240v applied to her. The news article mentioned an open circuit neutral was to blame I think. The girl survived the shock but she is now blinded and has other serious injuries, and at first she wasn't expected to survive at all. I'm not sure how that works in that a garden tap can become live without it blowing fuses or tripping some sort of circuit breaker.

Hi John, interesting video, I am curious as to why the voltage on the fluke meter was limited when you tested with both the 500v and 1000v ranges, Also if A.C. were flowing what would happen? Kind regards Warren

+John Ward So, question is, what are the risks of conductive water across an "insulating"-section? e.g. Can you start electrolysis of water, create hydrogen and oxygen? Will a shorter "insulating insert" still be 'safe' from the point of view of avoiding equipotential-bonding of a supply-pipe --- 5cm "insulating insert" with 230v across might give 25mA ? [a change in 18th edition may be coming in this regard?]. The danger comes from introducing a potential via the water when this was assumed not to be possible? Current-flow through your body through 180k resistance (for this length) was mentioned, but when would that situation occur -- only with lost-TN-C-S neutral scenario?

Would be interesting to check if there is a difference in the resistance when the pipe is pressurised and unpressurised, also with different waters, ie. rain water which should be a much higher resistance.

Hey John old one I know . How come we have tripping issues with joint boxes poorly sealed and water has got in ?

This is good example of why just because an incoming service supply is in plastic doesn’t automatically mean that protective binding is not required, as depending on the way a water pipe/gas pipe is installed a dangerous level of earth potential can still be picked up inside the property. Under 23k to earth based on 10ma current And also why addiction supplementary bonding may be required via high resistance plastic joints

Very interesting, thank you.

John, thanks for the video. Not an electrician but work as a mate (something to do in my retirement from industry). I've been studying your videos on Equipotential Bonding and don't fully understand the theory of it it all yet. Where does this video leave me if in a bathroom (say) the pipes under the floor are copper but change to plastic to feed the wash hand basin?

How hard would the water need to be before it does start to get dangerous? (or would the water hardness itself be a bit more dangerous before the electrical hazard becomes significant?)

Hi John, does this mean that supplementary bonding is not required to the metal parts if they are isolated by plastic pipes at both ends?

Interesting result, I wonder if it is because you have static water -- it has been shown repeatedly that a moving column of water is conductive enough to be significant. I was fault tracing some years ago in a restaurant bar where "potential shock risk" was reported (i.e. current above threshold of perception making the "ordinary persons" fear for their safety). It turned out the taps on the sink hiding under the bar gave a perceptible tingle especially when they were running. 100% inspection to every accessory on, under, behind and over the bar area showed that the bar was a later addition to the restaurant and installed almost like a prefab module, sitting atop the vinyl fake wooden floor and totally insulated from the room but with potential for static build up everywhere. numerous fridge units (compressors) and other Class 1 stuff like the glass washer and a few switch-mode psu's (the EPOS and others). No bonding in the whole area because the installer clearly didn't see a need. The supply to the sink was plastic, and GN8 of course tells us that if doing an R2 test (wandering lead back to the MET) shows a resistance >2kΩ then we can consider that item not to an extraneous-conductive-part. So when I dabbed between the taps and the CPC of the closest accessory (a worktop socket) I saw only 2-and-a-bit kΩ, but when I turned on the taps and let them flow at a decent rate, it dropped to a bit under 2kΩ. I added local equipotential bonding and the problem vanished. TL;DR: classroom maths theory or a carefully controlled lab experiment, like this, shouldn't always be taken at face value. The theory is sound and demonstrated well (I'm especially a fan of the old Fluke 1653 with the Robin branding proudly in place;-) but field experience can differ significantly due to many other influences... For instance,the contentious new Reg's regarding incoming services with a short "insulating section." It is no longer necessary to apply equipotential bonding (although confusingly it doesn't say that main bonding is unnecessary). Do you bond it anyway? Depends on if there any issues in the property. Yes? Bond the damned thing! No? Don't bond it in case you introduce a ground potential that wasn't there before.

What does this same about bonding a house installation when all of the pipe runs to a bathroom, for example, are plastic whist there may be metal parts in that bathroom. Is it still necessary?

This is seriously good stuff. No need for paranoia next time I shower (by coincidence the same Triton Cara model that Big Clive did).

Hi John, 2 bar is quite substantial! Kind regards Warren

I would like see what happends if the voltage is applied over time (also AC vs DC). (maybe even fill in on some common faults that can lead to it) Just the basic circuit: water mains on one end, closed tap on the other. The pipe in the video is a good model for that (maybe add a overpressure valve.. tho)

Realy interesting video!

must admit i always did wonder... thanks

Interesting test, I'm surprised the value was so low. Wonder how much this will vary depending on the water supply.

That horrendous solid plastic mega looks great. Has it had a video of its own.

Can you send a tone down a water pipe using a transmitter so that it can be located with a locator?

In our location most of new tap water installations that use PEX use PEX-AL-PEX which has an inner aluminum vapor barrier, surrounded by PEX. The Al doesn't come in contact with the water normally and the fittings also don't make contact so in effect the pipe is nonconductive when new. The question is, what would happen when over many years perhaps the inner plastic layer cracks? This would lead to the pipe effectively becoming conductive, would the pipe be treated as conductive ie. requiring bonding?

Very interesting. Should repeat the experiment with the pipe then drained of water.This would act as a control to see how much effect the water has

There are now many instant water heaters on the market that have a bare (uninsulated) heating wire exposed to the flowing water. Before and after the heating element there are serpentines built into the plastic so you get a certain length of water column for insulation. The installation instructions specify you may only use them up to a certain conductivity of the water and to inquire with the water company if you are unsure. These are fully certified units for the european market made by top brands, not some chinese Ebay crap, the Stiebel Eltron DNM 4 is one example. You can find a schematic picture if you google "blankdraht heizsystem". It scares me a bit, what if you are in the shower and some contamination comes through the pipe. I hope they put a grounded section at the output!

Have you a video showing how water is so dangerous in shower or bath. Thanks for this video

Can u run the test again with 22mm pipe to see how much better the resistance would be?

water between two rods make very large capacitor, so when you use AC voltage the condectivity very high

Pure water i.e. distilled water has very high resistance and can essentially be considered non-conductive. It’s all of the minerals, chlorine and other contaminants that makes water conductive. Pressure will also decrease resistance to a small degree.

Good to know👍

With the water in a plastic pipe only conducting a very small amount of current, is there any point in bonding the copper tube section on an incoming water main, where it’s entering the building in MDPE or any other plastic? Maybe I’m being simplistic, but I thought it was to ‘ground’ a faulty system? Thanks John very interesting as always👍

So what are the implications for earthing points? A lot of houses use copper water pipes as an earthing point, but if there's a plastic section in the pipe between the earth point and the mains water inlet, it's no longer providing a good ground connection right?

Thanks John interesting. What would happen if you just replace a copper fitting with a push fit plastic fitting. Would this have implications to the earthing arrangements within your property.

I sometimes get statically charged and open the water tap in my kitchen, only getting a shock when I touch the water stream, instead of the metallic handle. Isn't that weird?

I think you would definitely feel the wobble from >1ma, you can often feel current in the micro amp range from the leakage in transformers and AC adapters with the back of your hand.

Would it still trip the RCD if rain water got into the back of a socket from a leaky roof?

interesting, thank you.

Could you do a video giving advice to young apprentices, i've just finished my level 3 qualification and i'm hoping to get an apprenticeship to become more qualified as an elctrician e.g AM2, electricians card, 18th edition ect. love your videos

And if a metal (lead) main is attached to a plastic street main?

I worked on a shower unit where the element was in a clear plastic tube inside the enclosure .I removed the cover to test voltage and resistance and finally restored the supply the local means of isolation was in another room (eg through the wall from bathroom to kitchen )however when I returned the valve had failed to open and the element had melted the tube in less than 20/30 seconds max .The resistance of the water must have been similar to that on this test and added to that the resistance of the element !!!Not a good set up and this was before RCD protection !!

Which is why you don't get electrocuted when your immersion heater rots away

As long as the pH of the water stays below 7, the water won't become conductive. I worked on a HPA using a water cooled tetrode, it had a long coil of rubber hose carrying the cooling water and pH monitoring. If the pH rose the 20kV+ anode voltage would start to get shorted to earth down the water column in the hose.

what about the same test with flowing water?

The upshot is if your leccy shower somehow goes live and your bath has plastic pipes and there are no earthed metal pipes to touch you should get no more than a tingle

There was an electrocution on internet where unearthed metal/pole lamp holder in garden became live at a pub. I think water got into the lamp. Can this cause the metal pole/lamp holder to become live and allow enough current to pass to kill. Probably very little distance between the live wire and the metal lamp so water resistance might be a lot lower than your experiment in this video. Could you do a video on this ??

Why would the tester not test the full 500 or 1000v?

2 bar is approximately 29.4 PSI IIRC

Conductivity depends on the minerals in your water supply as John said, . Add salt and watch its resistance drop dramatically 😉 there's another video..

A human would feel 1mA but it wont kill, if you had used pure water (as pure as they use to jet wash extra high voltage power lines) it would not conduct, how water conducts is hugely dependent on its purity, some areas will be worse than others! It would be interesting to know if an old pipe with a lining of "crust" performs any differently?

Hi JW, thank you for all your very valuable and education videos. In one of your videos you introduce different amperages on a conductor to test connectors. What device are you using for different amperages ?

Throw some table salt in the water for a completely different result. And watch out for hydrogen/oxygen being created.

Chic sandals. Nice.

So those tests were made with direct current, giving an idea of the water resistance. But of course the mains is AC - so it would be interesting to see what current would flow through the pipe with an AC test current?

The closed pipe isn't pressurised at 2 bar. The pressure from the hose going into the pipe was at 2 bar.

That would depend on the ion content of the water!

If you dissolve lye in there you'll have a very conductive aqueous solution - but even that wouldn't compare to copper or aluminum at the same cross sectional area.

What's that 'robin' logo on the fluke megger? was very pleased to see the reappearance of the wind up chinese item btw... more cranking of handles = more entertainment thanks for that.

What about flowing water?

2bar isn't really that much, is it the normal pressure you have over there?

Obviously a video for the ladies - John Ward wears figure-hugging t-shirt and manhandles his impressive pipe

Would it be any different with distilled water?

Wonder how well it would work as a load.

I notice the "GENUINE PLASTIC SCREWS" on the megger screen surround Nice .......😂😂

I can vouch for the fact that water in plastic pipes & small plastic tanks ( such as shower units ) are capable of giving you as nasty shock, as this happened to our son when the element tank on our shower unit split. BTW good video, but please get yourself some decent trousers instead of those chavvy things, trousers befitting a man of your interllect

Would be interested to see this repeated with distilled water - think water cooled HV RF amplifiers...

So now what if you put the mains through it?

Hi JW. Could you possibly do a video regarding power factor? You always explain everything so well. Thanks!

Pure water is an excellent insulator, what you have is not pure water ... water cooled stator bars in a 23kV turbo alternator perform very well with very low (electrical) leakage.

Deionised water does not conduct electricity. Water must have an electrolyte added for it to become conductive. By the way, it's not made of H2O either. May I recommend Peter and Pete's channel for demonstatrable proof of my statements. One may also learn more than one expects.

1.2milli amps of current...? I guess you are saying that it is safe for me to use my 230volt electrical equipment with my acrylic bath with my plastic H + C pipework. We all can put up with a little tingle!

I figure it is it's just how conductive

Yes

Should probably be tried with hot water too, conductivity is noticeably higher as the temperature goes uo

Fresh water is relatively "safe". Next try it with brackish or salt water...

Shed catflap. Nods of approval all round.

So, how faulty boiler heaters kill people than? Distance Is significantly more than 1m, and voltage 220V? Thanks

add salt to this water ;)

Use deionized water next time

OK hook one end to mains voltage hold the other end and with your other hand earth yourself if you believe your words

"So I've filled the pipe with water" would have sufficed! :-)

That was a bit of an odd test...

why doesn't the resistance decrease with more voltage applied?? ohms law and plastic water pipes don't go together?

You guys have pretty weak water pressure, I'm used to about 6 bar here in the states...

pure water is not conductive at all. So the question is how contaminated our tab water is ?

All this achieves is to demonstrate basic ohms law. Resistance doesn’t change with applied voltage. Very very DANGEROUS comments at the end, THAT water in THAT pipe may have a set length and cross section but that won’t be the case generally. A series resistance with a human doesn’t guarantee safety when a voltage is applied, the critical parameter is current, and anything more than about 25mA can be fatal.

No