Why do my 2-pin TV and HT system give shock on ports when ON together?

[pussifer]

TL;DR

Why my 2-pin TV and HT system give shock on ports when ON together? (both connected to same extension box) Can it damage them? Can I fix it with a local earth rod for extension board near my room? My house has earth at the main but its poor & covered

does this condition damage the TV or home theater over time (HDMI ports, components, etc.)?

can I create a local earth connection just for my extension board by driving a metal rod into wet soil near my room and run a wire connecting it to the extension box earth pin?

will that help, and is it okay to do?

my house has an earth at the main but its poor & covered with concrete

 

[berkeman]

Welcome to PF.

What's a "2-pin TV and HT system"? There are two pins in what way? How do you get the shock? When you touch what or when you touch what two things?

Can you say what country you are in? What do the AC Mains power cords and wall receptacles look like? Are they grounded?

 

[pussifer]

Welcome to PF.

What's a "2-pin TV and HT system"? There are two pins in what way? How do you get the shock? When you touch what or when you touch what two things?

Can you say what country you are in? What do the AC Mains power cords and wall receptacles look like? Are they grounded?

I’m in India, so the mains supply is standard 230–240V.

By “2-pin TV and HT system,” I mean both my TV and home theater come with 2-pin plugs (live + neutral, no earth pin)

The setup:
TV and home theater are powered through a stabilizer and a extension board

wall socket > stabilizer > extension board > TV & HT

Home theater is connected to the TV via HDMI

The issue:
When both TV and home theater are ON, I feel a mild tingling shock when I touch metal parts like HDMI or USB ports on either device
If I turn OFF the home theater, the shock disappears

If only the TV is ON, I don’t feel it
I’m not touching two devices at once — even touching a single device’s metal port is enough to feel it when they're both on.

Also, even if I disconnect the HDMI cable, the tingle is still present when both devices are ON (maybe slightly less), so HDMI doesn’t seem to be the main cause.

Regarding grounding:
The wall sockets in my house are 3-pin, but the earth connection seems weak or ineffective
I tested using a small bulb and the glow between live and earth is very dim, which suggests poor grounding

Let me know if you need any more details.

 

[James Demers]

Sounds like your neutral wires are not properly grounded at the distribution box where power enters the house, where there should be a connection between neutral and a true ground. You could ground to a water pipe, if allowed by your local regulations, but it's generally frowned upon as it can shock water company workers. Best solution is a new grounding spike, as you suggest, but connected to the neutral line on the far side of your fuses or breakers.
If it's just your TV and HT devices that are affected, it could be poor isolation in the stabilizer or extension board. Replace the guilty party with a higher-quality item.

 

[pussifer]

Sounds like your neutral wires are not properly grounded at the distribution box where power enters the house, where there should be a connection between neutral and a true ground. You could ground to a water pipe, if allowed by your local regulations, but it's generally frowned upon as it can shock water company workers. Best solution is a new grounding spike, as you suggest, but connected to the neutral line on the far side of your fuses or breakers.
If it's just your TV and HT devices that are affected, it could be poor isolation in the stabilizer or extension board. Replace the guilty party with a higher-quality item.

Thanks for the input.
Just to clarify, both my TV and home theater are 2 pin double insulated devices, so they do not use earth internally. The issue only appears as a mild shock on metal ports when both are ON, and disappears when one is turned off, which makes it seem more like cumulative leakage rather than a neutral fault.

Also, I am not planning to connect any ground rod to neutral. I am not messing with my mains wiring (I've no electrical engineering knowledge) and can only make changes at my extension board level.

My main concern is whether this condition can damage the TV or HT over time

 

[Averagesupernova]

You only have one appliance that you get a tingle from and only when it is turned on. My suspicion is that device is faulty. Does it matter if you plug it into mains on different circuits in the house? I know the complexity and size is limited in India so maybe you have only one circuit you are able to plug into. Try it at a friend house. The fact that you get a mild shock indicates to me the earthing rod is adequate. That is part of the path that your body is part of when receiving this tingle.

 

[pussifer]

You only have one appliance that you get a tingle from and only when it is turned on. My suspicion is that device is faulty. Does it matter if you plug it into mains on different circuits in the house? I know the complexity and size is limited in India so maybe you have only one circuit you are able to plug into. Try it at a friend house. The fact that you get a mild shock indicates to me the earthing rod is adequate. That is part of the path that your body is part of when receiving this tingle.

Thanks, but it is not just one device.

I get a mild shock on both the TV and the home theater when they are ON together. If I turn OFF the home theater, the shock disappears on the TV, and it works the other way as well. That is why I am thinking it is more like cumulative leakage, especially since both are connected to the same extension board.

I have also tried plugging the TV into a different socket in the same room and keeping the home theater on the extension board, and in that case I did not get any shock on either device.

I want to fix this issue and be able to run both of them together on the same extension board without this happening.

My main question is whether this condition can damage the TV or home theater over time.

 

[Baluncore]

I want to fix this issue and be able to run both of them together on the same extension board without this happening.

My guess is that one of them has a crossed A-N to make it N-E. Does one of them have a cable that can be removed, and plugged in the other way around, or are all plugs polarised to prevent a swap of the A and N? Try rotating a two pin power plug through 180° in the socket, that may temporarily fix the problem.

It is possible that one has a noise filter on the power input, that is capacitive. Maybe the shock is coming from the initial charging of that capacitance.

Two pin plugs should only be employed on small "double insulated" devices that have no protective earth, chassis, signal screen, or power output cable.

My main question is whether this condition can damage the TV or home theater over time.

If the devices are both turned on, before and while the interface cable is connected, there may be a momentary current that flows through a signal conductor, rather than through the back-shell, connected to the screening of the cable. The electronics that connects to that signal conductor, may be damaged.

Before turning on either device, plug in any interface cables that will be needed.