Is Nichrome Wire Hazardous?

hopefully you never have a voltage leak

20 volts.

Unless you're consuming it, I wouldn't think there was a problem.....E-cigs use the same type coil for vaping...I think the melting point is in excess of 1400ºC...

I probably shouldn't make any more solar powered cups of tea in this way then, I have already had two today. I see 12v ones on Amazon and Ebay that you put in a cup but people complain about them catching fire or the wires melting. Shouldn't be a problem for me because I would replace the wires with 12AWG or thicker silicone coated wire like that used for RC planes and put 4mm bullet connectors on it.

...and smoking has a remarkable safety record when it comes to encouraging customer base with new technology.

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Baaaaa-zing!

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Okay, joking aside. That really is a crappy argument and I only put it up there because it made me chuckle..

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Nickel and chromium compounds are often much more dangerous when inhaled. It would be interesting to seem if detectable amounts are carried over with the fog for various vaporizers.

Just heard this about e-cigs and related metal exposure.

Considered that only the wire gets submerged and not the connector block, how can electrolysis occur? Where is the electrolyte or is tea supposed to be one? Would the tea not warm up without the resistance too, just with 2 electrodes? Electrolysis towards?

Doesn't the tea go in after the water's already hot?

Thanks for replying.

My guess is that the experiment stands a very good chance. It can be easily monitored when checking the wire on consistency. Electrolysis will occur when the electrolyte contains enough salt and it should be noticeable in differences of the wire at the end vs. beginning or earlier by pitting.

This will only show after hydrogenhead gets us the results.

Tap water has about no electrolytic qualities and will also not shorten the DC current source considerably.

Off the record:

I refer to tests we did with submerging leaking amphibious vehicles in a test tank with sweet water. After getting the water pumped out, they were ready to roll again.

"...Electrolysis will occur when the electrolyte contains enough salt and it should be noticeable in differences of the wire at the end vs. beginning or earlier by pitting....."

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Hmm, well, if you are strictly speaking of arriving at hydrogen and oxygen, then potentially enough salt could impede that specific type of electrolysis, but generally that isn't the case.

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Salt (NaCl, for example) will alter the products, but electrolysis won't be cease. Below represents a simplified representation of one very frequent result.

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2H₂O + 2Na⁺ + 2Cl^- ---->^electrolysis 2Na⁺ + 2OH^- + H₂ + Cl₂

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"....Tap water has about no electrolytic qualities and will also not shorten the DC current source considerably...."

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Salinity provides a fair amount of conductivity for tap water from most place. Even when relatively pure water is used (and remember exposure to things like atmospheric CO2 will end up increasing the conductivity of what began as reasonably pure) and current through the water is not providing overt indication, ionization will increase beyond autoionization and with even a few volt potential, even if any gasses go into solution prior to breaking off as bubble, energy imparted is likely to be sufficient to begin producing a statistically distribution of various compounds from the available players....possibly including those from the infamous CrVI crowd, albeit at a very low rate. As those compounds are formed though, water purity is degraded and conductivity increases, and soon....it might be off to the races.

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.Last minute edit: I see that I misread your initial statement about salts and electrolysis.... the example reaction is still valid and important, there are lots of salt ions in typical tap water.

Electrolysis is the dissociation of dissolved ionic compounds as a result of current passed through the solute. In this case the majority of the current is passed through the wire, and the remaining stray current is not of an order of magnitude sufficient to cause serious electrolysis of tap water. The worry may be of leaching of nickel and chromium from the wire. Both are non-reactive metals and both are highly insoluble even in boiling water. Current passing through the wire is not going to accelerate the leaching significantly.

"...Electrolysis is the dissociation of dissolved ionic compounds...."

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No. Ionic compounds are already dissociated when they are solvated in a solvent.

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"...In this case the majority of the current is passed through the wire, and the remaining stray current is not of an order of magnitude sufficient to cause serious electrolysis of tap water...."

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While the majority of the current is probably going to pass solely through the wire, your analysis of the potential available versus required for electrolysis is severely flawed. Remember that this wire is being used as resistance (usually associated with small wind turbines, not sure why it might be required for solar as the OP indicates). As such it likely represents a very large portion if not the largest portion of resistance in the system, hence the need for water to cool things down in that location.

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That means that the largest potential drop in the system is probably going to be from one end of that bare nichrome wire coil to the other. I think 12 volts was mentioned.

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The minimum required voltage to initiate electrolysis in tap water is actually about an order of magnitude lower than the voltage drop likely to exist across the resistance coil in use. Just a few volts potential is sufficient for electrolysis of tap water. At very low voltage, it may take a little while to become obvious, but there are already very reactive species being set loose at the metal surface by that point....and it doesn't take a whole lot of hexavalent chromium before handling becomes something deserving of consideration.

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"...The worry may be of leaching of nickel and chromium from the wire. Both are non-reactive metals and both are highly insoluble even in boiling water....."

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The concern is not over amounts metallic nickel or metallic chromium becoming mobile. The concern is predominantly about chromium compounds, specifically those with chrome in the +6 oxidation state. Both soluble and insoluble compounds are unambiguous genotoxic carcinogens, though actually the soluble compounds are not quite as harmful as the insoluble ones.

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Remember that the size of the particulates resulting from the electrically induced corrosion will be tiny enough that the heat and convection in the water will easily keep most of it suspended.

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Nickel also forms both soluble and insoluble compounds and while those are worse than compounds with chromium in the +3 state, nickel compounds likely from this type of corrosion are pretty safe compared to hexavalent chromium compounds.

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Remember this isn't just a matter of just boiling (which in combination with low pH and chlorides can result in a number of aggressive corrosion mechanisms), but corrosion driven with the help of reactive species generated by electrolysis.

I shall have to refer you to your textbook of physical chemistry.

Ionic compounds are already dissociated when they are solvated in a solvent

Search again and you will find that some electrolytes dissociate almost completely (strong electrolytes) and others dissociate only to a small extent (weak electrolytes). This is most familiar with acids, but applies also to non-acid electrolytes.
Nichrome is an alloy of the metals nickel and chromium, possibly with some iron, so the next concept to review is the conversion of chromium to chromate. Nickel and chromium are stable metals, and nichrome wire is not going to dissolve easily. You will have to explain where the energy required to produce chromate from the chromium comes from.

You may refer me to all the books you like, but that doesn't correct the definition you used for electrolysis.
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While you are correct that different ionic compounds dissociate to different degrees in a particular solvent/temp/pressure, that doesn't in any way blur the the line between solvating and electrolysis. Ionic compounds are dissociated as they solvate in a solvent. [/p][p].[/p][p] Solvating is likely to occur more rapidly if electrolysis is also occurring due mostly to mixing that accompanies..Just so you are aware, I don't have to pretend familiarity with this topic (and it is obvious to me, that you do). I am well versed in various corrosion topics and have fairly extensive work experience relevant to this topic as it is of paramount importance to reactor water chemistry and steam plant chemistry.Rest assured, the nuances and peculiarities of nickel and chromium as it relates to corrosion in water are very familiar to me [/p][p].[/p][p] What you are missing here is that electrical potential of even a few volts especially in a water that is not basic is a special case for nickel/chromium alloys that would otherwise be very resistant to corrosion..You don't have to take my word for it, just get some nichrome wire or other high nickel chromium alloy wire, cut two pieces, and connect one end of one piece to one terminal of a 9 or 12 volt battery and the other piece to the other terminal and let the other ends dangle into a glass of tap water.It won't take lomg to see a change in the water and soo after that it will become clear that one wire remains shiny and the other is quickly corroding away

just get some nichrome wire or other high nickel chromium alloy wire, cut two pieces, and connect one end of one piece to one terminal of a 9 or 12 volt battery and the other piece to the other terminal and let the other ends dangle into a glass of tap water.

You are doing the wrong experiment. The OP's description is of a single wire through which the current flows, albeit electrolyte-immersed. The current directly through the wire is far greater than the current throughout the electrolyte. Electrolysis depends on current passing through the electrolyte.

So you figure that the two ends of the wire that are at a 20 volt potential difference are not transferring some electrical current through the water as well creating an electrolytic reactions at each end?

For electrolysis you will need 2 different poles (anodic and cathodic) and material will move places when a electrolyte is present and current is applied.

The current in the water will be very little compared to the current in the wire.

It is worth the experiment. Hydrogenhead can tell after many trials.

I am pretty sure a it's a well known process that goes on all around us every day.

The wire is a resistance wire and a potential difference of several volts will arise, which is all that is required. There is no requirement for the two electrodes not to be in contact or even been the same piece, only a potential difference is required, which is accomplished via resistance.

Let us return to the original plot. OP passes current through continuous Nichrome wire through water to heat it. You worry that the stray current through the water results in an increased production of dissolved metal which would be harmful if swallowed. How does this happen? The textbook says (and I do recommend you read the textbook) that if the electrolyte contains a nickel or chromium compound then passing a current will result in the reduction of the metal ion at the cathode, where it gets deposited. At the anode, whatever anions are present in the electrolyte will be oxidised and either bubble off as gas or deposit as a layer on the anode (thus incidentally decreasing whatever start currents there were in the first place). What does NOT happen is that the current leaches metallic ions out of the wire. The heat may briefly increase the solubility of the metals from completely negligible to slightly minuscule, but in no way does the passage of current improve solubility.

Thank you for that succinct answer. It is amazing to me how many posters are knee jerks. I've been known to do the same. Lesson taken.

More is required for understanding than simply reading the words in a text book, especially with such stubborn preconceived notions.

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Yes, reduction at one end and oxidation at the other end can and does result in changes in the amount of both soluble and insoluble compounds in the electrolyte that result from those chemical reactions.

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Please try the experiment I recommended earlier. Put two wires, one from either pole of a 12 volt battery into a glass of tap water. Use nichrome if you have access, but most any wire will show you results pretty quickly. You can even try to cheat if you have access to ultra pure water, but it will result only in a slight delay until enough CO₂ is picked up from the atmosphere speed things up.

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Once you note the changes, you can go back to the nameless textbooks you keep referencing and try to sort out what you didn't quite understand.

Are you equating a coil with of continuous wire with a resistance to create heat when amperage is passed through it with an anode and cathode dangling in a conducting solution? These don't seem to be equivalent conditions, but you are correct, I'm just reading about the idea represented by the OP.

Yes. The resistance of the wire allows sufficient potential to be maintained. The driving force in electrolysis and the electochemical reaction is not how may pieces the wire is divided into, merely the potential difference.

the potential difference is much greater on the two unconnected wires than it is on the coil, no?

Depends on the system specifics, but in this case, it has been stated that a 12V potential is developed, so it is reasonably close to two separate wires and a 12V battery.

Yes, reduction at one end and oxidation at the other end can and does result in changes in the amount of both soluble and insoluble compounds in the electrolyte that result from those chemical reactions.

Adding an electron at the cathode cannot reduce the metal any further, so the nickel and chromium remain where they are. At the anode adding electrons reduces the few nickel and chromium ions there may be in the solution to the metallic form and plates them on the anode.
The only explanation I can give for your fixation is that you are considering chromate or dichromate ions to be in the solution. To produce either of these you will need a strong acid which will not improve the flavour of the tea. Metallic chromium does not dissolve in water to produce chromate ions.

For anyone still doubting that this type of process can result in notable amounts of chromium and nickel in the electrolyte, just consider this recent report concerning e-cigs. "Vaping" is done by passing current through a nichrome wire. While the vaping juice is not tap water, it also isn't an aggressive corrosive agent compared to tap water either.

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Still there has been confirmation metal is carrying over in the vapor. It is important to remember these are small battery operated devices. The voltage drop is probably less than the device that was discussed here.

Actually the current in an e-cigarette passes through a mass-produced metal mesh. Have you considered the possibility that it is the loose metal particles which get released into the smoke rather than some metallic ions not previously existing in the solution?

Actually, many are just simple round or flat nichrome or kanthal wire. There are numerous videos on youtube detailing construction of such vaporizers.

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Nichrome wire is readily available and it apparently works just fine. I haven't seen anything about nichrome mesh being used. Perhaps you could link a source of nichrome mesh used for vaporizers?

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More importantly, why would it matter if the current had a choice in paths? One wire, two wires, a grid, a mesh, it makes no difference.

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And no I don't think un-rinsed metallic ions can be blamed. I doubt they would deliver the wire (or mesh as you propose) un-rinsed to the manufacturer. I doubt the manufacturer would deliver the completed vaporizer un-rinsed to the end user. I doubt the researcher would test the vaporizer without investigating and/or insuring the initial cleanliness.

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This will be so much easier, if you will just develop a 12 volt potential difference across nichrome wire in tap water. You can do it the easy way with two pieces or you can end up pumping a lot of current through it while you maintain a 12 volt potential difference across one long piece. Either way, it won't be too long before you will see evidence that one end of the wire is indeed being degraded and much of the resultants end up in the water.

I doubt they would deliver the wire (or mesh as you propose) un-rinsed to the manufacturer. I doubt the manufacturer would deliver the completed vaporizer un-rinsed to the end user.

Given the well documented reports of other manufacturing failures (Stryker hip replacements, PIP breast implants) I doubt the ethics of all volume manufacturers are as spotless as you like to believe.

It is getting more and more difficult to continue to give you the beneffit of the doubt that you are not missing the point out of spite.

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My assumption about cleanliness did not rely on the chance that a wire manufacturer did not ever ship any product that was not reasonably free of easily rinsed metallic ion contamination that you propose.

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Let's take a step back and review exactly what it is you are proposing as a way other than electrolysis that the vapor became contaminated with nickel and chromium compounds. As I understand it, you are suggesting that metallic ions that would easily be rinsed into the e-cigarette liquid, left over from some part of the wire manufacture process, was present on the vaporizer wire when the researcher tested the device.

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If that is roughly what you are claiming, understand my skepticism does not hang on the infallibility of the wire manufacturer. I agree that not every product leaving a manufacturer is perfect. I also know that tolerances for small resistance wires are reasonably tight in most cases, and the chance of a spool leaving out of spec ior dirty s probably pretty small, although it probably happens. Now realize that it isn't enough just for the manufacturer to be less than perfect.

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The small chance of a contaminated wire being shipped, also has to pass the chance of that particular wire being shipped to the maker of the vaporizer that will be used in the test. Furthermore that manufacturer must fail to wipe of or rinse that very same sample of wire with the easily rinsed metal ions you claim, during the assembly and packaging of the particular e-cigarette that will be used in the test. Once again, not impossible, but once you multiply that small chance by each of the preceding small chances, you are quickly getting into the realm of highly improbable.

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Once you figure any techniques used by researchers to get a fair statistical sample of what is on the market, the likelihood that this is related to the original wire manufacturer sending out a dirty product is really really slim.

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"When you hear hoofbeats, think of horses not zebras"

- Dr. Theodore Woodward

I would guess (not done this) that unless gas bubbles form on the wire at each end (oxygen/hydrogen), the amount of electrolysis can be safely ignored.....

Whats your take on that idea for a test procedure?

From most tap water the initial gasses evolved are likely to be hydrogen and chlorine.(due to chlorides and possibly chloramines, related to natural salts and water treatment). Oxygen production will increase as chlorine is depleted.
Remember none of these are stripped as whole ready made lower reactivity diatomic molecules...what results from the stripping initially are the highly reactive atomic species.

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It doesn't matter if the wire is two pieces, ten pieces or one piece. The requirement is for potential difference not number of seperate pieces. Resistance wire allows sufficient voltage potential to be maintained with only one wire.

The reason I suggested the experiment as I did was because it will elucidate the effect from electrolysis alone and it avoids the much more significant set up required to establish the potential difference for sufficient time by dumping current through a resistance wire..

Perhaps if they just consider the experiment set up a special version of resistance wire with a higher resistance water gap center section...

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A lack of noticeable buildup and separation of bubbles is insufficient to rule out electrolysis and the corrosion consequences inherent therewith.

The resistivity of nichrome is 1.1 x 10^-6 ohm.m.
The resistivity of drinking water is 2 x 10^1 to 2 x 10^3 ohm.m

You tell me how many electrons are going your way and how many are going my way :)

This could be hazardous. It might cause health problems if you consume 20 cups of tea per day, heated this way, after 20-30 years.

I suppose it shouldn't hurt then. Great idea when there is a power cut.

Replacing the electrical assembly with a large magnifying glass would have the same effect without the nichrome exposure.

The danger is mainly in the possibility that you will be generating hexavalent chromium compounds. If the surface is rough or if cracks or loose connections occur, the risk of creating CrVI compounds increases. Certain impurities could also increase the risk.

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Overall, the risk is low, but it is probably a good idea to avoid further consumption. Risks will be pretty much negligible if you aren't drinking or inhaling the stuff.

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Besides using distilled water and making sure you have good connections and smooth surfaces, you can also reduce CrVI to much more friendly CrIII compounds by reducing with ferrous sulfate.

You are right about the electrolysis with the voltage drop across the wire.

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I do have to disagree with your characterization of trivalent chromium. Trivalent chromium is an essential nutrient. While required levels are low, it is definitely necessary. The risks from excess CrIII are things like skin rash and it is not known to be a carcinogen.

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Nickel isn't as benign, but the threat in this type of situation, unless exposure by inhalation occurs, is minimal. Any risks pale in comparison to CRVI.

If you want to dump 300w watts at 20vdc why not use it is for something that can be more productive and useful than the occasional, or frequent, cup of tea?

24 volt vehicle cab heaters are available is sizes below to well above 300w and in configurations including panel, ducted, enclosed and others. These are usually used on some trucks, heavy equipment and some aircraft. For instance one is available for about $120 US.

"Direct Hook-up 12 Volt or 24 Volt 300 Watt Back Seat Car, RV, Van, Boat, Trailer & Cab Heater"

This one is rated at 600watts on 24v but has a thermostat to lower output, temperature and thus the input current. But there are many others. http://www.sportsimportsltd.com/12vocarvvabo.html

During cold days a ducted unit could be directed to the inside and on hot days to the outside. You wouldn't have to waste the excess power on a dump device during cold days, use it to take the chill off.

Good Luck, Old Salt

Umm, wasn't the time to ask this question (here or elsewhere), before you drank the tea?

But for a solar panel why do you need a dump load at all??????? In the case of wind mill, without a dump load and wind is blowing- the wind turbine and the generator can run very fast, generate higher voltages and bearings may get damaged. In the case of solar panels- even if the sun is shining brightly and there is no load at all - open circuit voltage could go up from say 20V to 22 V or so. No damage is ever done.

Hence no one ever uses a dump load concept in the context of solar panels.

I was using it because my grid tie inverter broke. I have ordered replacement mosfets for it. I understand that my solar panels can't be damaged by a no load condition but I was wanting to make maximum use of the available power.

I remember when nichrome immersion heater water kettles were in every home (in Oz)

Porcelain jug with a bakelite top that couldn't be opened when the cord was plugged in.

These went out of vogue as a broken lid was potentially lethal. Also if boiled dry the nichrome element would fuse. Easy to fix just by twisting the fused ends back together...now days electric kettles use sealed elements.

I do not recall there being any health issues associated with nichrome element, potable water boiling.

I was going to ask here if anyone from Oz remembered them, are any still around? Can you still buy them? I saw then in S.Africa too in the 60's....Once they get coated with calcium in hard water areas, they should be safe....

Do the elements (Nichrome) cause problems with spelling, like missing out parts of words when speaking and writing?

Like "G'day?"

This from ebay OZ;

Exactly!! Shame no picture of the inside element available....

That's the one! The same cord female end could also plug into the toaster.

I remember them well. The elements were cheap and a good high power 1 or 2 OHM resistor. Used one in a strobe for studio use.

If I remember correctly chrome causes ulcers and as stomach ulcers were common place 'way back when' it is possible that the kettle caused some of them.

Jim

Why not just use 24v incandescent lamps for the load? No water issues.

I believe steam kettles are nichrome elements which are isolated in a bath of distilled water and the heat is transferred through a skin of stainless steel for cooking. No direct contact of food with the element is allowed.

Use mini induction heaters and avoid crome plated intestine.

Mini-induction heaters wouldn't meet the 'inexpensive and robust' criteria that I imagine is a non-negotiable requirement of this device.

Nickel-Chromium wire is used as an alloy for Type K thermocouples. Unlikely that it is hazardous. Did you drink the tea, and how do you feel now ? Therein lies your answer...

12v+water+heater+element

Most of these are safer (lower shock hazard) and approved for potable water heating. Suggest you buy one for beverages and save the DIY one for non-potable experimentaion only.

I seem to remember hearing somewhere that the boiling aspect is a major issue. Hot or boiling liquids are more reactive and can leach more contaminants out of things lk heating elements etc - by whatever process including electrolysis. The red hot metal of the heating wire is also far more reactive as well. I also seem to remember something about free ozone ions in boiling water.

This heat reactivity issue is a major reason why all heating elements in modern boiling vessels (for human consumption use) are electrically shielded and isolated inside stainless steel covers. (Apart from the obvious electrocution/short circuit problems with mains.)

I'm sure I read it on an internet site somewhere - probably Wikipedia.. :)

Red hot and in water, will need huge amounts of power....

In practice, the wire will seldom exceed the boiling point of water, unless it boils dry!!

Oops! well hot if not red hot..

I will never drink such tea, it will not taste same as boiled on gas stove or electric hot plate. I suggest try to make hot plate with nichrome wire and make tea on same. May be there will be some energy loss.

Induction heating of pots and pans is VERY economical and clean......only the pot gets heated!!

hydrogenhead-

Although a "cold one" has been my favored beverage since youth, I am more familiar with coolers than heaters. I remember from those ancient days that the immersion heaters used for heating liquids such as tea, coffee, soup, etc. were not bare nichrome wire. They had the wire enclosed with an aluminum tube that was a few wraps of a aluminum tubing formed into a coil. The nichrome wire within the tubing was insulated from the aluminum by insulating spacers. Aluminum was used due to its compatibility with food, easily cleaned and its the favorable heat conduction properties. The plastic handle was the part to grip it and provided a terminal/juncture area for the supply wiring and the element.

Bare non-insulated nichrome wire immersed in a water based solution would therefore be an unusual situation.

I remember this from my youthful "investigative" years when very few things had any chance of not being taken apart to find out "how does this work?"

Good Luck, Old Salt

The jugs from Oz have a heating element similar to the first picture here on this blog, but wound on a piece of ceramic.

They are dangerous if dropped on a hard floor, water and power under your feet!!

Also open to the water:-

Just looking at one of the Ebay adverts - also no safety or thermal cut out. So if you leave the jug it will eventually boil dry and probably catch fire. Lethal.

I never said they were safe.....I was appalled when I first saw them.....

In the early '50s I remember using a "fishing worm digger" that was nothing more than a stiff wire with a handle and a 120V plug/cord. There was probably a current-limiting resistor in the handle, but I didn't yet know about current limiting. One simply plugged it into a socket and stuck the wire into the ground. If it didn't work, you reversed the position of the plug.

The worms would come up by themselves, just like they do when you are digging nearby.

I never used one here, but I have been regaled many times as to good they work......

I would make one with a 1:2 dropping and isolation transformer and then start with say a 500KOhm resistor.....

dkwarner-

Yes they are good, I have found many "wormies" that way for trout bait. Just remember to wear rubber boots and gloves in case you touch the wrong parts while it is energized.

An apparatus based on the same principal can also be used to catch fish. It stuns them and they float to the surface. A net is all that is necessary to get them in the boat. This is illegal in many states but legal in some. Fish and Game personnel use this method to take censuses of fish population in bodies of water. They can do this either of two ways. Shock them and count them as they float on the surface prior to them recovering is the less accurate and provides only minimal data. The more informative way is to shock them, net each, weigh each, tag each, take notes and return them to the water.

Good Luck, Old Salt

Back in the 60's we made our own. Out of short lengths of ground rod, ground rod terminal, old extension cord and some electrical type. Those thin rods they had on the commercial one bend too easy. Works pretty good at getting worms. Works even better if you saturate the ground first.

Word of warning. In this leisure activity the hunt for worms. Do not take part in another leisure activity search for that perfect buzz what ever your poison. As forgetting to unplug the device used in the first activity will ruin the buzz in the second.

Same time period for me. Much more fun then!

Our "worm catchers" were home made also. Rod handles were wooden with rubber or plastic bicycle hand grips to reduce the buzz. Our favorite place was in a chicken pen. Plenty of moisture and salts to be very conductive. Hardest part was finding enough extension cords to go from the neighbor's house or barn to the chicken pen. Second choice was the barn yard.

Good Luck, Old Salt

dkwarner-

For what it is worth- I once got a shock, mild one that is, from a 12 volt boat battery in a centerboard sloop sailboat. Won't go any further than to say I was well grounded with my finger on the battery main supply wire. Worst part about it was having my wife see my reaction to the shock and see me figuring out why it happened. Was able to reproduce it to validate my reasoning.

Good Luck, Old Salt

ouch, Old Salt. May I hazard a guess, with that voltage, that it was an arc fault, and a burn, rather than a shock, which would be very difficult to produce at that voltage.

Back in the '50's I remember heating hot water in the bathtub with a small device that I took apart later. It consisted of 2 plates about 2"x3" separated by about 1/2" in a small metal jacket with holes...it plugged directly into he 110v outlet and would heat the tub in about 10 min. I discovered that the tub, water, etc. were 'hot', same as sticking a finger in a lamp socket. Interesting revelations for a 5 year old.

When, not if, they boiled dry then the element fused.

Porcelain jug did not catch on fire.

There are numerous high temperature alloys that are called nichrome, but can contain cobalt, iron, and some other metals. I suggest you avoid chronic use of this method of heating.

So many answers with people diving off the deep end like a bunch of lemmings. People have been heating water for drinks for years with coils of nicrome wire. We were selling them in the 50's for both 6 & 12vdc and 120 voltAC in our electric shop in a small town. The old ones last forever. They had porcelain insulators for heat and electrical insulation. I know people in my home town when I returned for a few years that were still using them in the early 2000's that were in their 90's. They were great back then before the microwaves came out. I think maybe some of the people on this forum should get a day job to keep them occupied.

LOL!!

perhaps you meant "load", not "dump load". There is no need to create a dump load for a PV array. Opening the circuit (like all charge controllers do) when you no longer need power (some controlled combination of voltage/amperage that is useful) for charging or inverting, is perfectly safe and economical, not to mention, ideal in most circumstances, as it is a very robust solution.

I concur with other Posters here who have warned you not repeat this experiment. I think it unlikely that you actually produced any Cr (VI) - the one that causes leukemia/cancer. Even if you only produced Cr (III) and some Ni (II) in small quantities (low concentrations), you really do not want to ingest that. Get your trace minerals from red vegetables, celery, and greens. Nature is kind enough to package these in a assimilable form (unlike many of the diet supplement pills).

Use a cup heater - the element is insulated electrically. Or run a fan, or a small cooler, or get more batteries and charge them.

And for crying out loud, go get a new grid inverter, and stop playing around with safety.

There is really no point getting a new inverter when new mosfets can be bought cheaply.