Laptop shocks me when food grinder is turned on in kitchen

[lesnar]

Hi,

Recently, I have noticed a very odd thing.. Need help from you guys.

I am using my laptop which is connected to AC mains. I am also using my wired earphones which have some metallic parts like the volume control. Normally when I touch this metallic part of volume control or any metallic part of laptop, I dont get any kind of electric shock..

Now here is the interesting thing.. When my Mom in kitchen connects the food grinder to AC mains and turns it on, then I get a electric shock on the metallic part of volume control on my earphones and other parts of laptop. Also I hear a buzzy sound in the earphones when the grinder is turned on.

This electric shock is a quite painful.

Any reason why this is happening and how to avoid it?

Regards.

 

[telectrix]

grinder may be faulty or you may have a poor installation earth. either way, get it checked over by an electrician.

 

[newfutile]

Does this laptop have a CPC (earth) ? All my laptops are supplied by a figure 8 power lead, if yours is this type then i would suspect the transformer (power brick), if you have an AC meter you could measure (in fault conditions) between metallic parts and a known good earth (socket screw)

 

[pc1966]

Does this laptop have a CPC (earth) ? All my laptops are supplied by a figure 8 power lead, if yours is this type then i would suspect the transformer (power brick), if you have an AC meter you could measure (in fault conditions) between metallic parts and a known good earth (socket screw)

Some laptops have a "functional earth" just for mains filtering. Not sure if that extends to the DC side of things but it would be a possible path for 0.5mA or so which in your ears will hurt!

 

[pc1966]

As above, almost certainly some serious wiring issue that needs attention before it causes injury or death.

 

[Lucien Nunes]

Not sure if that extends to the DC side of things but it would be a possible path for 0.5mA or so which in your ears will hurt!

Yes, it often does, sometimes via a resistor chosen to be low enough to drain off the capacitive leakage that gets across to the secondary side, but high enough not to set up a ground loop with external devices. 1kΩ is typical and used in most grounded Apple adaptors for example.

So the likely explanation is that the grinder produces earth leakage, either due to a fault or possibly just through its motor suppressors, and that the earthing to this circuit is broken somewhere. The earth leakage then passes from the motor to the laptop power adaptor and through its internal functional ground connection to the laptop. The circuit should be checked.

Note that the OP is in India where some practices and standards are comparable with UK practice but not everything.

 

[static zap]

Is the laptop a Lenovo ? ( a mate had one ! )
That was earthed !

 

[lesnar]

Thank you all for your replies...

To answer few questions,

I have a HP Elitebook 9470m laptop with original power adapter.

Actually a few weeks back when my mom was using the grinder, a loud noise came from inside as if something broke. We gave the grinder for repairs at a local roadside electrician.
Actually I dont remember whether the laptop started shocking after or before the grinder repair.

I am thinking of getting the grinder repair rechecked.

 

[pc1966]

I am thinking of getting the grinder repair rechecked.

You should be looking at the general wiring in the home first.

If the grinder has a fault then it should be tripping out circuit protection, that is fundamental to electrical safety for anything that has exposed metalwork. Yes, maybe the grinder is at fault but what you are reporting implies the basic house wiring is failing to provide that essential protection against the risk of a potentially fatal electric shock.

 

[lesnar]

You should be looking at the general wiring in the home first.

If the grinder has a fault then it should be tripping out circuit protection, that is fundamental to electrical safety for anything that has exposed metalwork. Yes, maybe the grinder is at fault but what you are reporting implies the basic house wiring is failing to provide that essential protection against the risk of a potentially fatal electric shock.

You are right.. Firstly I will ask an electrician to check the house wiring.

Thanks.