component grounding

Did you guys forget that on the positive side of the circuit there’s either a fuse in the fuse box or a circuit breaker. So even if you’ve got one hand on something that’s ungrounded and you happen to touch something that shorts out… then you’re either blow the fuse in the wall or tripped the circuit breaker and/or any fuses that are inside the amplifier. There is lots of safety built into the whole system. I was told that’s why our appliances run on 120 V 20 A maximum. That’s because even if you end up grabbing a hot wire with your finger and you happen to have the other finger the ground wire or the neutral it’s not going to kill most people. It might screw up someone’s pacemaker and in a very rare instance might hurt someone. I’ve done it numerous times probably once every few years over the past 20 years of construction work. Either I got zapped by a tool for a bad extension cord or a wire etc. our system is pretty safe. I know there’s outlier situation but it’s pretty rare of hearing of anybody getting electrocuted from a home appliance. 

Yet search as I may, I can't find one situation where someone was killed or seriously injured from an ungrounded piece of audio equipment.

None of them are around to give their testimony anymore.
(They are all wearing halos now 😇)

Raysmtb, fuses and circuit breakers are to hopefully keep your house from burning down in an over-current situation. You can be electrocuted many times over before a breaker trips.

Did you guys forget that on the positive side of the circuit there’s either a fuse in the fuse box or a circuit breaker. So even if you’ve got one hand on something that’s ungrounded and you happen to touch something that shorts out… then you’re either blow the fuse in the wall or tripped the circuit breaker and/or any fuses that are inside the amplifier. There is lots of safety built into the whole system.

So even if you’ve got one hand on something that’s ungrounded and you happen to touch something that shorts out…

Say what???

.

If you get between a hot 120V line and a grounded object, say from one hand to the other hand you will have a 120V potential from hand to hand. The resistance from one hand across the chest, through the heart, to the other hand can average around 1000 ohms, more or less. Really dry calloused hands the resistance might be as high as 100K ohms.

Amps = voltage / resistantance.

120V / 1000 ohms = 0.12 amps. (120mA) (Ventricular fibrillation of the heat)

If you cannot let go quickly the resistance can drop to 500 ohms or less.

120V / 500 ohms = 0.24 amps. (240mA) (Ventricular fibrillation of the heat)

In either case if the amp rating of the fuse in the equipment is greater than 0.12A or 0.24A it will never blow.

Forget about the regular 15A or 20A circuit breaker in the electrical panel tripping.

If the breaker in the electrical panel is a GFCI, and is operating properly, it will trip open between 5mA to 6mA.

.

Electronic engineer here. I was tinkering with a tube (valve) amp when 14 years old and got a bad shock. My father (electrical engineer) was an expert witness for some investigations into death by electrocution.

I recommend taking every step necessary to avoid having a mains electric shock. On this side of the Atlantic, mains is 230V. Building standards (UK) require that gas and water pipework is earth-bonded where exposed and all sockets to be protected by RCDs.