Equipment fuses are not designed to protect you from electrocution, but the safety ground (that nuisance that audiophiles love to remove) and Ground Fault Current Interrupters are (like the outlets in your kitchen, I hope).
GFCI trip at around 5 mA. That’s MILLI-amperes, while a circuit breaker is around 15 A, and typical audio gear in the range of 1-10 Amps (typical, not exhaustive.
Let’s say a tube preamp has a 1 Amp fuse, that’s 20 x more current than would trip a GFCI. The figure I read most often is that it is estimated that that about 10 mA of current is lethal under ideally fatal conditions.
Preventing damage from lightning is a difficult thing, in no small part due to the speed caused by the sudden arcing. Parallel systems require time to activate, series do not. Parallel systems rely on the drain location being low impedance, series do not.
An EMI pulse from a lightning (or nuclear) strike can induce current in the cables in the walls themselves, it does not necessarily telegraph in from the transformers. Series devices present a very high, always on, impedance to these rapid pulses, so the majority of the voltage will be presented at the blocking coil, instead of your precious gear.
There are also other sources of induced surges. Cable TV, phone and network wiring. Then there is stupid stuff like wind gusts on an antenna. I’ve suffered several losses of Satellite TV receivers not from lightning but from wind, I assume caused by static electricity developing across the broad antenna surface... and zap! Solved eventually by using a professional, bullkhead mounted surge arrester! :)
Best,
Erik
GFCI trip at around 5 mA. That’s MILLI-amperes, while a circuit breaker is around 15 A, and typical audio gear in the range of 1-10 Amps (typical, not exhaustive.
Let’s say a tube preamp has a 1 Amp fuse, that’s 20 x more current than would trip a GFCI. The figure I read most often is that it is estimated that that about 10 mA of current is lethal under ideally fatal conditions.
Preventing damage from lightning is a difficult thing, in no small part due to the speed caused by the sudden arcing. Parallel systems require time to activate, series do not. Parallel systems rely on the drain location being low impedance, series do not.
An EMI pulse from a lightning (or nuclear) strike can induce current in the cables in the walls themselves, it does not necessarily telegraph in from the transformers. Series devices present a very high, always on, impedance to these rapid pulses, so the majority of the voltage will be presented at the blocking coil, instead of your precious gear.
There are also other sources of induced surges. Cable TV, phone and network wiring. Then there is stupid stuff like wind gusts on an antenna. I’ve suffered several losses of Satellite TV receivers not from lightning but from wind, I assume caused by static electricity developing across the broad antenna surface... and zap! Solved eventually by using a professional, bullkhead mounted surge arrester! :)
Best,
Erik
