7 ms·

I have this problem in India. I suspected the mains was dodgy, because during the many power outages i never got the shocks when on UPS. I got a multimeter and

I have this problem in India. I suspected the mains was dodgy, because during the many power outages i never got the shocks when on UPS. I got a multimeter and measured. The neutral was 70V and the phase 300ish. So the difference was roughly 230V but a switched power adapter would make this hover around 70 too (I believe an old coil based would probably been fine). The Indian electrician didn't understand my problem because his only tool was a regular bulb with two exposed wires that he jammed into the socket. "Look sir, light, power working" sigh.

ars 10y ago
The 70v is probably induced voltage at milliamp levels. You can fix it by bonding the neutral to ground at the breaker box.
- kosma 10y ago
  This is potentially deadly advice. A neutral/grounding fault will energize all your home devices with live potential; same with a live/neutral swap (unlikely but possible with Indian wiring standards).
  - xenadu02 10y ago
    > This is potentially deadly advice. A neutral/grounding fault will energize all your home devices with live potential; same with a live/neutral swap (unlikely but possible with Indian wiring standards). You are wrong. In the US the NEC requires this. If you bother to look inside your breaker panel you will find the neutral and ground wires are literally screwed down to the same bus bar. Any path your body (or the soil outside) can provide back to the generator pales in comparison to the neutral tap provided by the transformer. Grounding to dirt is about static electrical discharge, not the voltage provided by the generating station. The safety of providing a grounding wire is that metal parts of appliances must be connected to that ground. The ground wire itself is both bonded to neutral and connected to a metal grounding rod driven into the dirt. If any part of the appliance's internal works becomes energized and touches the metal casing the direct path to ground is designed to create a short circuit and trip the breaker immediately, rather than sitting there waiting for a human to come along and complete the circuit. If ground weren't bonded and the ground dried out or the grounding rod weren't properly installed then the scenario you describe would occur. A single faulty appliance would back-feed voltage onto every grounded appliance in the building. So in fact bonding is what creates safety, not the other way around.
    - kosma 10y ago
      > In the US the NEC requires this. If you bother to look inside your breaker panel you will find the neutral and ground wires are literally screwed down to the same bus bar. It could be different in US, but in modern European installations the PE and N bars are separate; older installations use common PEN; and even older ones don't even have PE. Each of the wiring schemes requires different approach and poses different hazards. There's no single recipe that would work on all of them. My bottom line is: don't make arbitrary connections in the breaker box without proper knowledge and training; and don't give random electrical advice on the internet without knowledge of local codes.
      - xenadu02 10y ago
        > It could be different in US, but in modern European installations the PE and N bars are separate In the US a single PE+N wire feeds into the building. All building wiring is separated as in Europe. They are tied together in only one location, usually wherever the main switch is. Just like Europe, really old installs in the US don't have ground (PE). Some are retrofitted with ground like my house in SF. One thing people should never do is connect neutral to ground at a secondary point. It can be tempting when you don't have access to run a ground wire but creates a serious potential for safety problems. The way to handle that is to install a GFCI (RCD) plug and put a sticker on it stating "No equipment ground" - the outlets actually come with those stickers for that purpose :) As far as I know in European systems where the building has separate PE+N feeds they are still bonded together, it just happens at the transformer. I could be wrong about that though!
        deleted 10y ago
        [deleted]
        zyx321 10y ago
        In separate PE+N systems, the feeds join at a single master GFCI (typically one per distribution panel)
    - sangnoir 10y ago
      > You are wrong. In the US the NEC requires this. OP's very first sentence clearly stated they are in India, where this is obviously dangerous advice because most devices (and piping) connect their surfaces to Earth, which is new Neutral.
  - jjawssd 10y ago
    My 120 volt inverter installation manual required me to wire one of the 120v outputs to a solid ground.
  - algesten 10y ago
    Yes. In my previous place in India the RCD was repeatedly tripping up. Earth here was a metal rod into the ground, and I only found out much later they fixed the RCD issue by disconnecting the rod and I started getting electric shocks from touching my fridge while my crappy toaster was connected. That's when I decided to not mess with electrics in India. It's dangerous enough as it is. As for the 70V, I eventually managed to reach someone in the electrics company that understood my issue, and they told me a local transformer for the whole street was broken. And they didn't have any plan to fix it.
ganeshkrishnan 10y ago
I had the same problem in Australia. I thought it was just me being over-sensitive to static electricity
- dogma1138 10y ago
  You are probably connected to poorly grounded socket or a socket where hot and ground were switched. I had a grounding issue and I used to get shocked by my tower all the time, this is pretty common.
  - derekp7 10y ago
    Same here, with some PCs back in a shop area. Come to find out, the outlets weren't getting a good ground due to painted conduit. And without a good ground, a cheap surge suppressor ended up dumping about 30 volts into the ground pin.
- shakna 10y ago
  It took me 6 months to get PowerCor to understand the shower was trying to use me as an earth, because they couldn't reproduce it. They told me I was just being sensitive, despite every flat reporting similar issues. The hot water pipes were being used as the earth, and the electricity could leap across the pipe in bad weather.
londons_explore 10y ago
Neutral can be as high as 400v relative to earth and the power still be within specification. 30 volts is more typical though. It's the devices responsibility to design for that.
deleted 10y ago
[deleted]
Hydraulix989 10y ago
Shark used to make an (otherwise excellent) upright consumer vacuum cleaner with a metal strip in the handle. The vacuum's power cable did not have a ground. This vacuum had the most five-star reviews on Amazon, but then a minority of people started complaining and leaving one-star reviews, saying they were getting shocked. The reactions from the fanboy crowd were non-sympathetic ("you're imagining it," "it's just static," etc.), and they mass downvoted every one-star review. Some of the people claimed they were getting shocked PRETTY HARD, too, as in it knocked them over. IIRC, even Shark responded saying that it was impossible for the vacuum to shock you. I remember seeing this while looking at vacuums for my elderly mother who has a heart condition. To the electrical engineer in me, everything made sense! I started defending every single one-star reviewer person, and I wrote my own very detailed review with photos of the handle. Soon, the tide turned, and more people started upvoting my review than downvoting it; and I even received personal "thank you" messages from the people who got shocked ("finally someone believes me"). It eventually got to the point where a year later in 2014, Shark released an updated model with no more metal strip. Seeing this, I bought the new model for my mother. I'd like to think I can give myself SOME credit for causing them to do that. Not only that, the upvotes from that alone were a good part of the reason I became an Amazon Top Reviewer.
- nraynaud 10y ago
  I would separate the issues, vacuum cleaners are famous for electrically charging dust up to quite high voltages.
  - Hydraulix989 10y ago
    I should clarify that the reports indicated that the shock originated from the hand touching the handle.
    - nraynaud 10y ago
      I guess I should go further: some vacuum cleaners have to have a ground connection in the hose, to try to discharge the dust. If they removed it for unrelated reasons, they probably lowered the overall quality of the product overall.

ars 10y ago

The 70v is probably induced voltage at milliamp levels. You can fix it by bonding the neutral to ground at the breaker box.

kosma 10y ago
This is potentially deadly advice. A neutral/grounding fault will energize all your home devices with live potential; same with a live/neutral swap (unlikely but possible with Indian wiring standards).
- xenadu02 10y ago
  > This is potentially deadly advice. A neutral/grounding fault will energize all your home devices with live potential; same with a live/neutral swap (unlikely but possible with Indian wiring standards). You are wrong. In the US the NEC requires this. If you bother to look inside your breaker panel you will find the neutral and ground wires are literally screwed down to the same bus bar. Any path your body (or the soil outside) can provide back to the generator pales in comparison to the neutral tap provided by the transformer. Grounding to dirt is about static electrical discharge, not the voltage provided by the generating station. The safety of providing a grounding wire is that metal parts of appliances must be connected to that ground. The ground wire itself is both bonded to neutral and connected to a metal grounding rod driven into the dirt. If any part of the appliance's internal works becomes energized and touches the metal casing the direct path to ground is designed to create a short circuit and trip the breaker immediately, rather than sitting there waiting for a human to come along and complete the circuit. If ground weren't bonded and the ground dried out or the grounding rod weren't properly installed then the scenario you describe would occur. A single faulty appliance would back-feed voltage onto every grounded appliance in the building. So in fact bonding is what creates safety, not the other way around.
  - kosma 10y ago
    > In the US the NEC requires this. If you bother to look inside your breaker panel you will find the neutral and ground wires are literally screwed down to the same bus bar. It could be different in US, but in modern European installations the PE and N bars are separate; older installations use common PEN; and even older ones don't even have PE. Each of the wiring schemes requires different approach and poses different hazards. There's no single recipe that would work on all of them. My bottom line is: don't make arbitrary connections in the breaker box without proper knowledge and training; and don't give random electrical advice on the internet without knowledge of local codes.
    - xenadu02 10y ago
      > It could be different in US, but in modern European installations the PE and N bars are separate In the US a single PE+N wire feeds into the building. All building wiring is separated as in Europe. They are tied together in only one location, usually wherever the main switch is. Just like Europe, really old installs in the US don't have ground (PE). Some are retrofitted with ground like my house in SF. One thing people should never do is connect neutral to ground at a secondary point. It can be tempting when you don't have access to run a ground wire but creates a serious potential for safety problems. The way to handle that is to install a GFCI (RCD) plug and put a sticker on it stating "No equipment ground" - the outlets actually come with those stickers for that purpose :) As far as I know in European systems where the building has separate PE+N feeds they are still bonded together, it just happens at the transformer. I could be wrong about that though!
      - deleted 10y ago
        [deleted]
      - zyx321 10y ago
        In separate PE+N systems, the feeds join at a single master GFCI (typically one per distribution panel)
  - sangnoir 10y ago
    > You are wrong. In the US the NEC requires this. OP's very first sentence clearly stated they are in India, where this is obviously dangerous advice because most devices (and piping) connect their surfaces to Earth, which is new Neutral.
- jjawssd 10y ago
  My 120 volt inverter installation manual required me to wire one of the 120v outputs to a solid ground.
- algesten 10y ago
  Yes. In my previous place in India the RCD was repeatedly tripping up. Earth here was a metal rod into the ground, and I only found out much later they fixed the RCD issue by disconnecting the rod and I started getting electric shocks from touching my fridge while my crappy toaster was connected. That's when I decided to not mess with electrics in India. It's dangerous enough as it is. As for the 70V, I eventually managed to reach someone in the electrics company that understood my issue, and they told me a local transformer for the whole street was broken. And they didn't have any plan to fix it.

ganeshkrishnan 10y ago

I had the same problem in Australia. I thought it was just me being over-sensitive to static electricity

dogma1138 10y ago
You are probably connected to poorly grounded socket or a socket where hot and ground were switched. I had a grounding issue and I used to get shocked by my tower all the time, this is pretty common.
- derekp7 10y ago
  Same here, with some PCs back in a shop area. Come to find out, the outlets weren't getting a good ground due to painted conduit. And without a good ground, a cheap surge suppressor ended up dumping about 30 volts into the ground pin.
shakna 10y ago
It took me 6 months to get PowerCor to understand the shower was trying to use me as an earth, because they couldn't reproduce it. They told me I was just being sensitive, despite every flat reporting similar issues. The hot water pipes were being used as the earth, and the electricity could leap across the pipe in bad weather.

londons_explore 10y ago

Neutral can be as high as 400v relative to earth and the power still be within specification. 30 volts is more typical though. It's the devices responsibility to design for that.

deleted 10y ago

[deleted]

Hydraulix989 10y ago

Shark used to make an (otherwise excellent) upright consumer vacuum cleaner with a metal strip in the handle. The vacuum's power cable did not have a ground. This vacuum had the most five-star reviews on Amazon, but then a minority of people started complaining and leaving one-star reviews, saying they were getting shocked. The reactions from the fanboy crowd were non-sympathetic ("you're imagining it," "it's just static," etc.), and they mass downvoted every one-star review. Some of the people claimed they were getting shocked PRETTY HARD, too, as in it knocked them over. IIRC, even Shark responded saying that it was impossible for the vacuum to shock you. I remember seeing this while looking at vacuums for my elderly mother who has a heart condition. To the electrical engineer in me, everything made sense! I started defending every single one-star reviewer person, and I wrote my own very detailed review with photos of the handle. Soon, the tide turned, and more people started upvoting my review than downvoting it; and I even received personal "thank you" messages from the people who got shocked ("finally someone believes me"). It eventually got to the point where a year later in 2014, Shark released an updated model with no more metal strip. Seeing this, I bought the new model for my mother. I'd like to think I can give myself SOME credit for causing them to do that. Not only that, the upvotes from that alone were a good part of the reason I became an Amazon Top Reviewer.

nraynaud 10y ago
I would separate the issues, vacuum cleaners are famous for electrically charging dust up to quite high voltages.
- Hydraulix989 10y ago
  I should clarify that the reports indicated that the shock originated from the hand touching the handle.
  - nraynaud 10y ago
    I guess I should go further: some vacuum cleaners have to have a ground connection in the hose, to try to discharge the dust. If they removed it for unrelated reasons, they probably lowered the overall quality of the product overall.