Electrical Shock While Showering

As per electricity is concern grounding is a main issue.

Starting from our substation transformer to our distribution (step down transformer) we assume that all grounds are same (zero Potential). some time it may not so because of interferances or some time people connect neutral in to the ground line or vise versa. so shocking may occur without switching on the appliances.

Now a days electronic UPS also giving this problem (last week i got this problem in our lab) still we have no solution for this. simply we put some rubber mat and now we are working on it.

So i am also eager to find a better solution for this (earthing) problems.

Thank you,

K.P.mahalingam,

Electrical engineer,

India.

Hi mahalingam, You mentioned a problem with an UPS;

"Now a days electronic UPS also giving this problem (last week i got this problem in our lab) still we have no solution for this. simply we put some rubber mat and now we are working on it."

If you are getting a shock from the UPS there is something wrong and it needs to be investigated pronto. The rubber mat is not a solution so shut the UPS down immediately.

Thee are a couple of common installation mistakes that electricians that are not familiar with UPS installations make that could cause this problem.

Firstly if your UPS has an isolation transformer that completely isolates the system from the mains the secondary side of the transformer needs an EARTH NEUTRAL link. If you don't put this in the voltage across the secondary terminals will be what you expect but when you check them to ground they may both be at a considerable potential. The circuit needs to be traced out and the terminal that is acting as the neutral needs to be connected to ground with a jumper.

Secondly there will be a certain amount of leakage from the batteries to the case the batteries are in. This is because batteries have lots of plates arranged in parallel and this gives them a certain amount of capacitance to ground. This will result in a voltage being induced on the case that the batteries are in so if this case isn't earthed you will get a belt from it. The higher the voltage and larger the batteries the worse this gets. I came across an installation once that had 150 VAC with enough current behind it to cause some serious pain and muscle contraction where the installing electrician forgot to earth the battery cabinet.

There are several more obscure things that may cause this problem but these are rare so you problem is most likely due to one of the above mistakes.

I reiterate, if you are getting a shock of the UPS there is something wrong so shut it down and get somebody that is qualified to check it out. If the people that supplied and/or installed the UPS tell you this is normal tell them to take it back and find another supplier and/or installer. It's not normal and it shouldn't happen.

Depends on the type of distribution system and the method of generating the hot water for the shower.

Suspect the insulation of the heater unit if the heating is being done electrically. Suggest a 30mA RCCD be installed in the supply cable regardless; if it doesn't reset, then the unit is faulty and needs to be changed for safety.

If not, suspect the earth path conductor between the distribution point and the installation. If the neutral is being used as the earth, a live/neutral swapover is one possibility, as is a dirty connection upon the neutral.

With an earth rod at the consumption point the problem may not arise.

A 30mA RCCD in the circuit to an electric shower unit is a requirement for new installations in the UK and its presence will be checked at the inspection in connection with compliance and certification with Part P of the Building Regulations for notifiable works.

"A 30mA RCCD in the circuit to an electric shower unit is a requirement for new installations in the UK and its presence will be checked at the inspection in connection with compliance and certification with Part P of the Building Regulations for notifiable works."

Sorry to hijack the thread but PWSLACK took me by surprise here. Up until July last year at least there was no requirement for a 30mA RCD on electric showers in the UK. Has Reg 601-09-02 of BS 7671 been amended since then?

Traditionally RCDs were never fitted on any instantaneous water heaters or immersion heaters as the leakage of such units caused nuisance tripping. Although things have improved the RCD requirement was not included in the 16th Edition recent amendments, despite the fact that some manufacturers recommend such action.

One other possible:

The electric wires for the room may be wrap around the water pipe and the insulation is breaking down such that some voltage is leaking throught and conduct between water pipe and water. I found out about this when I redo my bathroom and the contractor open up the floor and found the wires wrap around the water pipe. thank goodness the insulation is still intact, but I can't help think the possible danger that may be.

MidniteFighter

Possible items to investigate.

If the water heater is electric, open the circuit breaker feeding it and see if the shock goes away. If it does there may be a faulty heating element.

Being in "Cape Cod" as the sender indicates; and if you have aluminum conductors comming into you service panel from the electric company, the salt air may have damaged a neutral and/or ground. Verify very carefully.

Re-verify your cold water pipe ground to service entrance in the residence.

As far as the statement with UPS, are you running an isolated ground refference to the service or what is the KVA and Manufacturer of the Box.

Hope this helps.

If you are getting a shock in the shower, it indicates that the water supply (shower head) and the surface you are standing on (Shower floor, tub, etc.) are at different potentials (voltages). In a house with metal piping, both supply and drain are normally grounded. However it is common practice to use an insulating union where pipes of different metals (eg. copper and iron) are joined, to prevent electrolysis from eating away at the joint; so it would be quite possible for the house side of the supply to be ungrounded. In that case, as another post pointed out, a defective electric water heater element could put a charge on the water line. It is also concieveable that rats or other animals could have chewed away the insulation on a wire so it now touches a pipe.

In any case, get a long insulated wire, connect one end to a known good ground (a pipe very near where it enters the ground, or a metal rod driven into the ground - there may be one near where your phone line enters the house). Connect the other end of the wire to one side of an AC Voltmeter set to a scale higher than your mains voltage, and go around the house checking the voltage at every place where you can see a pipe, including right at the water heater. With a good digital meter you might be able to measure a different voltage at different locations; if so, the higher the voltage, the closer you are to the source of the problem.

If you have plastic supply and/or sewer lines, of course they will not function as a ground, but the water itself will have sufficient impurities to conduct enough current to be felt (absolutely pure water with no dissolved impurities supposedly does not conduct, but tap water has at least dissolved air, and most likely some acid from the rain and of course minerals if it has been underground, plus whatever has been added to purify it).

I would suspect a high resistance ground. The water heater would be #1 suspect. Check the terminal box connections. Make sure there isn't a strand of wire touching an adjacent terminal. It certainly is not a direct short, otherwise you would be in deep 6. It could be the heater element insulation is beginning to break down. Replacement elements are not expensive, so I would suggest you replace the element. If there is an earth potential high enough to feel, you could install a pipe clamp on the house side of the water line and use at least #6 bare copper wire and fasten it to the house ground rod. Also, another possibility is that the electrician failed to properly connect all the little green or bare copper ground wires during installation.

If you read very carefully the entry it sounds clear: somehow the piping is connected to the neutral of the power system.

An important unbalance sets a residual voltage on the neutral.

The last is not uncommon and when you know how transformers are used in the US it is quite normal that the system is in unbalance. The connection of the Neutral to the grounding is good but: you should never connect anything in your house to this grounding.

Now it seams that you have your water piping connected to the neutral grounding and some metal parts in the tub to the real ground.

Disconnect the grounding of the piping and change it to the grounding of your tub. Investigate this well as it could save your life or your customers life.

It might be that local legislations accept some voltage to be measured on metal pipework. If the soil is rather impermeable and dry the water pipes are the only possibility for the power company to have a decent grounding. The fact that they offered to do some changes shows that they are not sure of the situation either.

In Belgium this is prohibited and the neutral grounding needs to be separated from the main grounding of your house.

Two clues probably identify the problem.

Electrical shock started after the local utility worked on the line. The person had a problem with Local utility workers.

Call the local utility and report specifically that electrical shock initially occurred immediately after recent utility work. Ask the utility to specifically return and verify that the neutral and ground at the utility power supply pole is properly connected in accordance with local code. Follow up with a written verification of the conversation. After completion of the work, have the local certified electrical inspector to inspect the installation. There will be a charge of around $25 for the inspection. With a volt meter, you can personally check the voltage between the water pipe, the earth or house ground, and the earth grounding rod driven into the earth at the electric meter at the house mount. The earth ground at the meter may be disconnected, dirty, or non-existant.

What you described is a failure of the electrical utility workers to properly connect earth ground and/or the electrical neutral on the supply transformer or power supply pole near the entrance to your house.

In the UK, were the fault to be found upstream of the customer's meter, there would be no charge for this service.

What exactly is a 30mA RCCD?

In a single-phase situation, a device for measuring the current in the live conductor and the neutral conductor, which disconnects the supply if the difference in currents in those conductors exceeds 30mA.

"Earth leakage trip" would be a more vernacular description.

They are becoming more commonplace in the UK and are now a requirement for new installations on safety-critical applications for circuits feeding kitchen sockets, cookers, circuits going outdoors and electric showers. Plug-in add-on devices are also available, as are plugs with RCCD built in that are connected to the flexible cable feeding an appliance.

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RCD is a Residual Current Device/Detector

Another name is a RCCB : Residual Current Circuit Breaker

This unit compares the ingoing and outgoing current in an electrical circuit. When the difference is more than 30mA the circuit is isolated. Rearming needs to be done manually.

It is a typical European solution: All houses need to be protected by a device of 300mA and the circuits that enter wet rooms or feed apparatus that handle water need to be protected by a 30mA device. This is domestic usage, industrial usage simply imposes personnel protection as high as possible.

In North America this obligatory usage is not foreseen, apparatus safety moves the responsibility to the manufacturers, who impose it or build it in in their apparatus. Mostly a 5mA device is than build in. This shift of the device could create your problem: the power lines are not protected.

IEC regulations have build in the usage of the RCD: when a manufacturer demands it you must use it. We are working hard to impose it in every installation.

Would the RCCB be equivalent to the "North American" GFI (Ground Fault circuit Interrupter) device?

If the function of a GFI is similar to that of an RCCD...

The GFI device comes in 3 flavors: GFI outlet (on which we plug appliances), GFI breaker (replaces a normal circuit breaker to protect an entire circuit) and a portable device that is often used by contractors.

It has indeed the same functionality, the current at which it reacts is lower. These devices are in fact real Personnel protection devices.

18mA is sufficient to kill you, a normal circuit in a house can have a capacitive leakage current of 10mA. (depends on the quality of your wiring and the length) A 30mA RCD has a tripping zone between 15 and 30mA.

But as stated earlier: your wiring before the unit is not monitored: you could still be electrocuted by drilling into a live wire.

I think the center tap off the pole transformer has a problem. The neutral wire must have a bad connection or a broken splice. I've seen splices that look great but when you tug on them, they just fall apart. Corrosion at the connection points can also open the circuit. This side of the power meter should be checked by the power supplier.

Others here have given you good advise. Checking the water heater Circuit breaker panel, and other connections should not take very long for a qualified electrician, and you can present the bill as evidence you have checked for the problem, but could not find one, on your side. Maybe they will even pay it. If the electrician does find one and fixes it, then the problem is solved. No action is really not an option and I don't think much of the plastic pipe either. Water is a conductor too and electricity will find a path.

Something that I bring up here at CR4 every few months is the CRIMINAL use of acronyms. By the way CRIMINAL stands for

Confused Regional Interpretation of Multilingual International Nomenclature & Acronymic Language

Keep in mind when you post at CR4 it goes throughout the world and the use of acronyms varies dramatically from country to country. That doesn't mean you shouldn't use acronyms. If you are going to use acronyms then it's very helpful to you fellow CR4 engineers if you fill in all the words in the first instance then use acronyms after that.

So next time you go the use an acronym remember it could be CRIMINAL.

Just one question . . . . what is CR4 ?

it stands for "Conference Room 4"

Thanks. It was KOADSJ (Kind of a dry stupid joke).

Cheers mate, reading that has made me completely FUBB.

:) I had to look it up....

Acronym Definition FUBB Fouled Up Beyond Belief

Thank you masu!

I'm an ME but don't work with HVAC and I have no clue what SPU or AHU mean.

From Wikipedia, SPU can stand for:

• Seattle Pacific University
• Seattle Public Utilities
• Socialist Party of Ukraine
• Student Peace Union
• Synergistic Processing Unit in the Sony-IBM-Toshiba Cell microprocessor
• SubPicture Unit

• Split Airport has IATA code SPU
• Staplehurst railway station has National Rail code SPU

I once worked on a weapon program that had a half-inch thick manual defining acronyms just for that program. The military really gets things FUBAR using the same acronyms for different applications or programs and with different meanings. Just for drawings, ASME Y14.38M Abbreviations and Acronyms now replaces MIL-STD-12 Abbreviations For Use On Drawing and in Specifications. I thought SNAFU was mostly the domain of government control, but I see it is now pervading all sectors, especially with the advent of text messaging and people who can't type!

mycoman

"Something that I bring up here at CR4 every few months is the CRIMINAL use of acronyms."

Ill second that motion. Posters should assume everyone is, as if not more so , uninformed (ignorant) of the acronym as the next one. It should not be kept a secret!

If you really wanna bake some noodles, try using an Acrostic Acronym:

Swimmers
Cruising the deep
Underwater delight
Breathtaking as it is unique
Awesome

Travel
Among the kelp
Nature at its wettest
Keeping this beauty in your mind
Scuba

"...use of acronyms varies dramatically from country to country..." - Especially in Israel

The person experiencing this problem should definitely hire an electrician to find and solve the root problem.

Having said that a theoretical "temporary fix" would be to ground the tub, faucets and shower head to ground using copper grounding wire. That way they are all at the same electrical potential. This would stop the shock, but would not be a solution to the root problem. It might be a good idea to see what the difference in voltage potentials are between the tub vs. faucet/shower head since directly grounding a high voltage power source could cuase a lot of current to flow (tripping a breaker or running up the power bill at least) If it did trip the breaker then you would know what circuit had the wiring/appliance fault...

Get a professional electrician to look at this problem before someone gets hurt.

Shocks are purely because of internal wiring fault, particularly if there is no continuity in the earth line circuit for the entire house. The only safe solution is to install an ELCB, Earth Leak Circuit Breaker in your main switch board. Ordinary circuit breakers will only trip when there is overload or short circuit but it will not help you in finding the faulty earth line/current leak. Use a well knowledgeable technician to install this piece of protective gear.

Have a safe shower!

YES, YES,

It is not the house grounding!!!!!!!!!!!!!!!!!!!!!

Needless to say that is bunch of manure!!!!!!!!!!!!!!!!! to put it politely

This happens with dairy farms due stray voltage to the cow waterers and or a common waterer for the dairy herd and the cows refuse to drink and and eat and get sick and die due to the poor grounding of the electrical highlines-because elelctricity is lazy and will go where it wishes. This has happeneed many times

This problen is particularly accute with bovine livestock because they are in a wet environment and the concrete under thier hooves has reinforcement rod in it; hence it is a perfect conductor for even micro voltages which will have a detrimental effect on the cows health.

google (cows and stray voltage) and you should get a whale of a lot of information.

What ever you do do not believe the utility as you friend did not have the problem before they did the highline work!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

These poor magnificent animals suffer needlessly due to the stray voltage in the foundations due to the inadequate control of stray voltage/poor grounding etc.

Tell your friend to get a an independent electrical engineer to do ground checks and conductivity checks as the water pipes intering the home are a natural conductor-the plastic pipe will conduct static electiricty as well.

The water in the pipes is the ultimate conductor so thier statement using plastic pipe is of course ignorant and self serving.

Every time I've troubleshot an electrical shock problem in a barn or farmyard it has been caused by the grounding rods being disconnected, or missing. Most of the time it is because a sub feed panel was added after the barn was electrified, and no ground rods installed. When ground rods are added to the sub feed panel, no more shock and the problem is solved, or a circuit breaker blows, showing a shorted wire, heater, or fan or pump motor some where in that open circuit. Driving and connecting the ground rod allows enough current to flow from the short, back to the neutral wire, tripping the circuit breaker. Without the ground rods the current is forced into taking a much higher resistance path through the piping, soil, cattle, sheep, or farmer back to the main panel ground rods. The resistance in that path can be so high the current is limited to a level too low to trip open the breaker. But the current can still be high enough to shock or kill anything or one that offers a lower resistance path through even a small area, back to the main panel. Anyone that doesn't install a ground rod isn't going to pay extra for GFCI breakers either.

In building Substations, I've been known to install a ground grid and ground rods every 20 feet or so...

Most people think of electricity as always taking the path of least resistance. I say electricity will flow through all paths, most electrons through the path of least resistance, but some electrons through any path they can find, limited only by the resistance to electron flow in that path. You might as well give the electrons good low resistance path that you have chosen in advance.

Sparkchaser, you stated

"In building Substations, I've been known to install a ground grid and ground rods every 20 feet or so...:

"Most people think of electricity as always taking the path of least resistance. I say electricity will flow through all paths, most electrons through the path of least resistance, but some electrons through any path they can find, limited only by the resistance to electron flow in that path."

One thing that needs to kept in mind if you install multiple earth stakes is what happens during a lightning strike. When lightning hits the ground the current dissipates in radial manner from grounding point. This will result in quiet larger voltages being developed between points that are different distances from the grounding point of the lightning. If the two stakes are too far apart you can have large currents induced in the connecting conductor during a lightning strike.

A second problem that can happen is that with the two stakes you have the electrical equivalent of a loop of wire. Any loop of wire that is in a magnetic field that is varying in intensity will have an induced current flowing in it. As a result of ferrous items moving around and the variations in the earths magnetic field from transformers and the like you can get an AC current flowing through the loop. This can then cause noise on the earth and result in the dreaded hum and interference with electronic equipment.

"Most people think of electricity as always taking the path of least resistance. I say electricity will flow through all paths, most electrons through the path of least resistance, but some electrons through any path they can find, limited only by the resistance to electron flow in that path."

This is absolutely true, electricity will not only flow down the path of least resistance but will take any path it can find to ground. The current flowing down a particular path is inversely proportional to is resistance. The only way all the current can flow through the earth stake is if it has no resistance. Since you can never achieve a no resistance path to ground you will always get current flowing through any and all paths to ground. The idea is to keep the current through these secondary paths to an absolute minimum by have the lowest resistance to ground earthing system that is practically possible.

Masu,

A agree. Lightning always presents special problems not really addressed within this forum message.

Anytime electrical energy hits earth, be it from power line or lightning, it radiates in waves, like the ripples from a stone dropped into a still pond, from the contact point outward. It loses energy the further it travels from the contact point.

A Substation ground grid is designed to limit induced voltage in the tower superstructure or metal fencing around the substation. The ground grid has both length and width, and is designed to limit the potential energy from induced voltage in any metals in the area of the sub station by giving the voltage an easier path to ground than it will find flowing through a person. Ferris metal will develop induced voltage and so will non ferris metals such as aluminum. You tend to ground everything in a sub station. As an example of the unexpected, I have had to use all my strength to remove a steel crowbar from an aluminum buss bar in a smelter pot-line. 240,000 amps flowing through the buss bar caused the aluminum to become magnetic and attract the ferris metal of the crowbar.

Multiple ground rods offer less risk than not enough ground rods in a sub station. Two ground rods connected to a sub feed panel are much better than no ground rods in a sub feed panel in a barn, even if a bit extra electral noise is developed.

"A Substation ground grid is designed to limit induced voltage in the tower superstructure or metal fencing around the substation. The ground grid has both length and width, and is designed to limit the potential energy from induced voltage in any metals in the area of the sub station by giving the voltage an easier path to ground than it will find flowing through a person."

An earth grid is actually acting like a Faraday cage. By being connected as a grid it is ensuring that anywhere within the grid will have a neutral potential. I have seen a similar thing done in undeveloped countries where people live in huts or houses with no floors. People that live in houses like this are prone to injury and death by lightning strikes. The solution is to bury a loop of heavy un-insulated wire around the perimeter of the house thereby acting as a type of Faraday cage.

"Ferris metal will develop induced voltage and so will non ferris(sic) metals such as aluminum. You tend to ground everything in a sub station. As an example of the unexpected, I have had to use all my strength to remove a steel crowbar from an aluminum buss bar in a smelter pot-line. 240,000 amps flowing through the buss bar caused the aluminum to become magnetic and attract the ferris(sic) metal of the crowbar."

I am not sure that earthing can help with the magnetic field that is generated by the current flowing through a conductor. There is no absolute way to shield from magnetic fields, the best you can do is try and constrain them by enclosing the item with a ferrous material that has appropriate magnetic properties. Even this is not 100% effective, you just need to look at the extraordinary lengths they go to containing the magnetic field of Magnetic Resonance Imaging units.

Check all Plug points where any one may have the phase and neutral interchanged with ref to others .

A simple and direct solution is to connect a grounding clamp to the Hot, Cold, and Waste (Drain) lines as close to the shower as possible. Connect all three together! This will eliminate any possible shocks while showering.

The cause remains as to why.

Electrical codes, on wiring changes, now require 2 earth ground rods. A second ground rod is reccomended. Also, if any plastic piping has been installed, a ground wire jumper must be installed.

I re-grounded an entire liner type Olympic swimming pool if anyone is interested in that incredible story. A few shocks by the users on the hand rails, especially during storms (lightening).

Cliff Notes Version:

Equipotential grid built under the pool (pull up liner and slice up a grid system in the concrete and embed # 6 bare copper wires with 12'" - 16" square pattern, even up sides), walk ways, welded the top rail joints to each other and grounded all to a main ground ring and grid, Uffer grounds, ground rod resistance measurements, exothermic welding of each grid cross section, ground ring embedded around pool walkway, welded (not screwed) all SS hand rail joints and grounded to the ground ring, GFI CBs on all heaters, pumps, etc., checked for potential in soil and found utility had done some work (they screwed up their grounds) and also saw an old water heater in trash pile from neighbor and discovered he had CBs popping for that circuit . . . put a GFI CB in his load center for his water heater (and . . . it was a gas water heater . . . can't be too safe you know [just kidding]).

PetroPower you may be interested in a problem I experienced with a waterbed heater once.

If power was applied to the heater and the thermostat had interrupted the current anybody that was lying on the bladder would have approximately 140 V AC induced on them. If the thermostat turned the heating element on the voltage would disappear. Mains supply was 240 V AC 50 Hz.

The fault was never isolated and would manifest itself by giving anybody a mild electric shock similar to a pin prick if they contacted an earthed item. The fault was never isolated and the only thing I can think of was that the thermostat for the heating element was using a triac that was switching the neutral leg of the heating element. As a result when the element was turned off the heating coil was acting as one plate in a capacitor and thus allowing a certain amount of leakage to anybody lying on the bed.

I feel that the Gentleman concerned has received some brilliant advice from many people, but one point was not made fully clear with regards to the ELCB or RCCD device. If there is an earth fault current, it will keep tripping. Good, it will force him to get it resolved and not ignore it further.

It will also allow him to identify the circuit(s) with the problems very quickly as when that circuit(s) is switched off, the RCCD will not trip - simple ain't it?

Also, I once tripped a 35ma(?) ELCB with my finger, accidently you understand. It really hurt!!! But no damage, except to my pride!!

I echo you all in saying further:-

TAKE IT SERIOUSLY GUY AND RIGHT NOW! get it fixed.