Electric Shock ?

Thanks

Not in the UK it's not! All equipment fitted with 2 pin plugs must be double insulated for exactly this reason. One leaky cap' could make any metal lethal.

I can assure you it is common. But the amount of current leaked to the chassis and accessed via a phono socket screen etc is too small to be a risk. But you can still feel it under certain conditions.

It is a FACT that capacitors DO sometimes go short circuit and although it is some time since I worked on domestic equipment I simply cannot see a such potentially dangerous practise as caps' directly connected to external metalwork from the mains getting past the design stage.

I will check latest spec' and get back....

Any mains input filter I have ever seen, contains those capacitors,and all computers and periferal equipment have them . If they would not have them, they could never pass the high frequency leak rules, and your mains wiring would turn into nice transmitting arials so that all radios and tv's in the neighbourhood would become useless. Those filters look like a nice solid block,but inside are some blocking ferrite coils and decoupling capaciters to ground. And you should not use any hardware without a ground connection, it stops radiating interference, and without the ground connection you can blow your hardware when connecting a cable between them,even if they are switched off(when signalwire makes contact before the groundwire). It also stops you from feeling tingling (or worse). As for the capacitor going shortcicuit, as long as you are using ground, it will safely blow the fuse or the leak protection.

Those are X2-rated (or similar) capacitors. Manufacturer guarantees that they will not short circuit when broken. However, eventually some of them will (nothings perfect). So, current flows to protective earth and fuse blows.

As long as equipment is properly grounded, there's no problem. If it ain't, there might be lot's of 'em. Like burning the whole machine and getting electric shock.

Yes that is what the thread is about. 2 pin mains supply which probably won't be grounded so why should a person get a shock from touching a customer accessible part of the cabinet?

IIRC, they're not normally connected direct to the signal earth or case but via a high value resistor. And those don't fail short circuit.

RFI suppression using this sort of technique has been common for probably

Any resistor would make them totally useless. The cap resitance must be near zero for high frequency's.And plugging with power off does not protect your inputs,the filter comes before your main switch, and the cap current can damage a mosfet input,even if it is only microamps,the voltage is half the mains voltage,when there is no ground path.

I think you need to do some investigations into this as none of my HiFi TV DVD CD's or VCR's has an earth connection as its all connected via 2 core mains cables?????? and this is how it was designed to work from the manufacturers

No but resistors do change value. High resistance ones usually downwards.

"Good practise"? Err this is customer devices we are talking about....

BTW, I have just opened up my recent DVD player to have a look (UK) and there are NO capacitors going from mains to chassis.

A properly designed circuit should not radiate any noise. If it does take the equipment back to the supplier as faulty.