I have a friend who has moved to the Canary Islands (Spain) for a while. She has told me that there is a buzzing that she feels when she touches many of the electrical devices. I noted something similar when I was in Italy when I plugged in my laptop but the ground lead wasn't touching (strange plug on a power bar). In the Canary Islands, there is no 3 prong plugs, only 2 prong.

So what I'm thinking is that this is more than likely a grounding issue. I told her this and she told her landlord. He stated that grounding on volcanic rock is very difficult. Also, their water pipes are plastic, not metal like in the older houses in Canada, so grounding to that is not possible either.

So I have two questions:

  1. Is the buzzing just an annoyance or is it in any way indication of a possible situation that could happen that is more dangerous?
  2. She lives on a cliff overlooking the ocean, so I was wondering, if she were to get a big spool of wire, connect the offending appliances and the 3rd prong of her laptop to the wire, and throw the other end of the spool into the water (obviously stripping that end so that it is exposed), weighted down by rocks. Would that be an acceptable ground?
  • 1
    Yes, potentially dangerpus. it does sound like a faulty earth or neutral connection. but such ad-hoc methods seem dangerous. especially if it's a bad neutral. get a real electrician on site to check it out.
    – Jasen
    Dec 25, 2016 at 21:27
  • Finding a real electrician here is a real challenge. The largest cause of house fires here is electrical problems.
    – RoyC
    Dec 25, 2016 at 21:38
  • 3
    To whoever voted to close: this is not something merely related to using appliances, it is something related to the safety and design of the electrical system in which those appliances are used, so it is on topic. Dec 25, 2016 at 21:49

6 Answers 6


I am in the Canaries at the moment and their attitude to electricity supply and grounding is cavalier to say the least. There is no clear standard as to what is live and what is neutral. The plugs and sockets (Spanish) do normally have a connection for ground but what it is connected to is usually a mystery.

If she is there for a while I would suggest getting a long piece of rebar (2m+) and hammering it into the ground close to the building (diagonally will do if there is rock below). Make the earth connection to this.

  • An iron or steel grounding rod will corrode reasonably soon (unless protected with concrete which makes it a poor ground stake), copper or copper plated is usually used. Testing the mains sockets for ground would add to the piece of mind but might not solve the tingling.
    – KalleMP
    Dec 25, 2016 at 21:52
  • Rebar will do, the climate here is dry and corrosion is not usually a problem. If I was doing this for my own property as a permanent solution yes I would use copper.
    – RoyC
    Dec 25, 2016 at 22:02
  • She is right on the edge of the ocean, so it is not that dry. When she tries to heat her apartment, it gets very humid. However, she said she'll prolly not be there more than 6 months to a year.
    – Adrian
    Dec 27, 2016 at 20:41
  • 3
    RE your cavalier comment. Yeah, the landlord's brother is an electrician and said something to the effect that having a little jolt now and then keeps you healthy. o.O
    – Adrian
    Dec 27, 2016 at 20:43
  • 1
    Rebar would not be code for a driven electrode but galvanized pipe can be and it comes in 10' sticks a couple of extra feet compared to an 8' rod can make a big difference in the resistance of the electrode to earth.
    – Ed Beal
    Dec 10, 2018 at 18:16

It sounds like missing grounding but this is not always a danger sign.

If there is the tingling annoyance, this is often caused by suppression capacitors and bleeder resistors leaking mains into the chassis of the consumer device and not automatically a fault condition.

If however you have a robust metal cased appliance (old hand drill) with a 3 prong (or contact) plug and a 3 conductor cable (more often round than flat) and have only unearthed sockets to plug into I would take extra care with wet conditions or signs of damage.

If your devices (modern device with mains adapter) have a two prong plug (no earth prong, hole or clips) and a two conductor cable (usually flat rather than round) with a double insulated symbol or low voltage input on the appliance you are likely be be reasonably safe.

You can read the following Q&A for some thoughts on a similar issue. https://electronics.stackexchange.com/questions/271744/is-this-electrically-safe/271760#271760

Also if the house has a tested and working Ground Fault Interrupter the consumer earth connection is no longer quite essential as a shock preventer though it is still valid protection for cable faults.


So at the power entry, ground and neutral are bonded together. So if you are not grounded, then the neutral is not going to be very good. The last time I was ina building that had a hum like this, the ground was ok, but the neutral connection to the grid neutral was bad. So it stands to reason that if the neutral connection to the grid is ok, then your ground is bad.

Normally you go straight down to get a good ground. However many ground installations for things like radio towers will go down, but also fan out away from the tower. So if going down doesn't work, try trenching and burying as deep as possible a ground wire. A 6 gauge bare copper wire, burried in a 75' long trench is considered a reasonable lightning dissipation path for grounding, and these are run in multiple trenches radiating out from the point you are trying to establish a ground. If you can bury these at least a foot or two deep, hopefully in soil under w watered lawn, that would be ideal. For some critical tower locations, they would use water well drilling equipment to sink grounding electrodes. And for added grounding "power" the electrode might be hollow and filled with a rock-salt-like compound, and then put on a water drip system that periodically sends a couple galons of water down the pipe... with an access port at the top to pour fresh salt in from time to time.

The point is there are lots of ways good grounds are established, and saying the ground is too hard to do it right is a cop-out. Yes it can be difficult, but it is not impossible.

If you can pound a ground steak only 2 or 3 feet down, dig a trench, and plant a ground steak every foot, then run a heavy gauge bare copper wire in the trench, clamping it to every stake you planted... Cut the stakes off below the top of the trench, and then fill it all in with dirt. It's not as easy as a 8' ground rod sunk into dirt, but it isn't bad. Watering the lawn over the trench in a modest manner will improve the ground if it needs improvement.

Another common grounding technique is to attach to the steel rebar in the building's cement slab. The rebar in a poured slab is in quite good contact with ground, and makes a good source of grounding, as good as a water pipe. The slab holds some moisture, and thus the slab is as good a conductor as moist dirt.

I used to erect radio towers, and have seen a wide range of grounding systems used. I don't buy it that it is too hard to do. It may be too hard for someone being lazy, or careless... But it is hardly impossible. And as a DIY effort, just bury a 6AWG wire in a trench, and bind it to the outside of your electric meter of metalic conduit, and you should see a difference. Just be aware that as you connect the ground to the box, there could be some voltage potential there. It might not be much, but the energy from that hum is going to travel on that wire, so as you make the connection there will be some current flowing, so don't electrocute yourself in the process. You can measure the AC voltage between your new ground and the meter cabinet before you touch them together, in case you want to know how much potential there is there...

  • Ground rings are required to be not less than #2awg per NEC 250.52.A.4
    – Ed Beal
    Dec 10, 2018 at 18:20

We had a similar problem (getting "minor") electrical shocks from the ground pin of outlets, and by extension the metal casing of devices), also in an appartment in the Canary Islands.

We called in an electrician (a real, qualified one..).

It turns out that in these appartment complexes, the earth is shared between all the apartments, meaning that the earth wire from every appartment goes to the same earth rod.

In this case, someone's RCD in another appartment was faulty, and and an appliance was also faulty and sending a lot of current into the earth wire (up to a few amps)

The electrician told us that the earthing rod is not designed to take this much current continuously, which means that you have a residual voltage (in this case ~70 volts) on the earth wire, in all the apartments, which is why you get a shock.

The fix all be to turn off power to every apartment in turn to isolate the problem, and then get the owner to replace their RCD.

(And grounded, three pin outlets are definitely a thing in Spain, maybe not on older apartments though. The outlets have two contacts at the side of the socket for earth, they are not the same as the French ones.)


It's just a normal annoyance. The choice to ground a floating charged mobile is a safety tradeoff for the line filter noise to ground current you feel that suppresses conducted SMPS noise to AC line which can then radiate to AM radios inside home and cause a buzz interference on quiet channels. Instead you feel the buzz or tingle but design regulations limit this current by the X cap line filter to ground value to 500uA max, which is safe but annoying.

So it is an annoying tradoff when the charger is plugged in. It can be prevented but at the risk IF someone shorts line to ground AND if ground is connected to the laptop external frame but ground is faulty to both then the laptop farame become live. This double fault is very unlikely but any risk is avoided by making laptop floating. (something like this might happen by hap hazard maintenance person installing power and ground to appliances with faulty connectors or loose screws or poor quality outlets. This can easily be checked by a skilled technician with a milli-ohmeter. Due to the rare but possible risk , mobiles with metal frames are insulated, (not grounded) from Earth ground even if the chargers are 3 pronged.

Laptop supplies may be earthed on the primary side for a line filter but the leakage of modulated SMPS noise across the isolation transformer capacitance will leak up to 500uA of tingling RF impulse currents when also touching anything else nearby due to the common mode current loop of stray capacitance. I have verified this to be true on ASUS laptops.

Where ever there are leakage current between appliances and poor ground, it matters not if they are connected to Mother Earth or the Sea or plumbing pipes as long as they are all the same. So ensure your grounded appliances are common ground.

Now for safety reasons due to [potential] ground faults in other equipment becoming lethal, they chose to make Laptops floating. But this causes a nuicance leakage current to flow when touching the case metallic corners and having wet feet or touching any other metal electrical appliance. I found the simple solution to connect the VGA which ties the earth ground of the laptop to all other like grouneded units whether the outside ground exist or not. Of course you dont need to use a VGA cable just has ground pins. An alternative may be a a ground wire taped with packing tape to the ground studs or case or a dummy VGA connector with ground pins accessable by jumper clips. It reduces portability but eliminates the tingle. The other method is to elminate the ground leakage curent in the first place which unfortunately is there suppress RFI emissions for AM radio interference which few people care about these day, or simply run off battery.

For internal house leakage current have a common ground for floating AC powered units is all you need. But for external lightning ground currents a better connection to Mother earth reduces the hazard such as aluminum wire to the sea. However this becomes inductive and V can be induced with nearby Cloud to ground strikes from L * dI/dt so braided or coax wire is better.

  • Good idea, the screen of a USB cable may be a good grounding point. Just connecting a USB B end connector shell to a known good ground point would be a possible remedy for a laptop. Not a general fix for all other types of appliances sadly but a free test.
    – KalleMP
    Dec 25, 2016 at 21:55
  • Thanks for the response, but I'm a little confused by your answer. This is what I got from your answer: 1. The buzz is caused by floating ground, but 2. the chassis is insulated from the ground due to safety reasons. So, my new question is how is there a buzz when there is no ground in place. Is this induced into the chassis?
    – Adrian
    Dec 27, 2016 at 20:34
  • Also, you talk about a VGA connector. She has a laptop and no VGA monitor. This is a Mac, so if it has any video connector, it prolly has a Display Port. In any case, were you suggesting that I ground to the VGA connector of the laptop? Is this directly to the laptop chassis or the 3rd prong? If the former, wouldn't that defeat the insulation to ground? If the latter, I'm still uncertain how the grounding of the 3rd prong results in stopping the perceived vibrations when dragging ones fingers across the laptop cassis.
    – Adrian
    Dec 27, 2016 at 20:37
  • Yes the former defeats the insulation to ground by shunting the nuisance tingling current. Since the finger is about 100pF range. method you can try is a <=1nF cap bypass the higher frequency leakage pulses but not pass 50/60-Hz line in case of a live ground fault. Dec 27, 2016 at 22:04

If her outlets are 2 wire outlets, then they aren't grounded. More than likely the neutral(Grounded Conductor) isn't bonded to the ground (Grounding Electrode system) at the meter/main (First point of Disconnect) because there may not be a Grounding Electrode (Ground Rod, Ground Loop, etc.) available. By the sound of her landlords brother, it's possible the power company doesn't even have a ground at there distribution transformer. I would tell your friend, that until she moves, when touching the metal attached to the outlets and switches (i.e.cover plates, screws and such), to have either shoes or gloves ON (preferably rubber soled shoes and or DRY leather or rubber gloves). To get tingled she's becoming a conductor completing an electrical circuit and until this brother gets serious, this is the a temporary somewhat safe solution. I've been a master electrician since 1984 and a Journeyman Lineman prior to that training. Namaste

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