For example, 110% of 230= 253 volts. Assuming L and PE are of the same size and material, indirect contact touch voltage is 126.5 volts. Would 0.33 seconds not appear more realistic?
From IEC 61200-413
mapj1:
The fact I say 'current' and not 'voltage' is significant. Skin resistance of 5k-50k ohms per square cm of skin means that only a large area contact will get anywhere near the 30mA of the RCD threshold, in turn based on the lethality date. Shock current in terms of contact resistance is the single biggest variable in all this.
Skin conductance per area should be treated with caution when getting to small (few mm2) areas and large proportions of 230 V across the skin. When applied voltages are over some threshold, typically below 230 V (e.g. 200 V) skin can quickly become more conducting. This is included in some plots in IEC 60479-1. For example Fig.5 (2018) shows the 1 mm2 contact resistance collapsing to around 7 kΩ around 220 V (50 Hz) compared to over 200 kΩ at 200 V. The quick transition is labelled 'rupture of skin'. Ok, that figure is only based on 'one living person': a lot else about impedance with substantial voltages is on larger numbers of corpses. But I can verify tripping a 30 mA RCD from contact of a 1.5 mm2 conductor-end (from a cut-off wire, insulated except the 1.5 mm2 tip) on a palm, with 230 V, when the other body connection was a good one; it left a white spot. As long as there are fairly poor contacts at both the 'entry' and 'exit' then the split of 230 V between them prevents this level of skin voltage being achieved.
(Following a recent discussion of units, how should that skin 'resistance' be described? It may be 5 to 50 kilohms for a 1 cm square [for a given voltage and condition], but saying e.g. "50 kΩ per cm2" suggests 500 kΩ for 10 cm2. Instead, writing as 50 kΩ·cm2 would be the strange-sounding way that shouldn't be able to be misunderstood. Alternatively 20 µS/cm2. Yes, I know no one who thinks about the subject would misunderstand anyway...)
mapj1:
The fact I say 'current' and not 'voltage' is significant. Skin resistance of 5k-50k ohms per square cm of skin means that only a large area contact will get anywhere near the 30mA of the RCD threshold, in turn based on the lethality date. Shock current in terms of contact resistance is the single biggest variable in all this.
Skin conductance per area should be treated with caution when getting to small (few mm2) areas and large proportions of 230 V across the skin. When applied voltages are over some threshold, typically below 230 V (e.g. 200 V) skin can quickly become more conducting. This is included in some plots in IEC 60479-1. For example Fig.5 (2018) shows the 1 mm2 contact resistance collapsing to around 7 kΩ around 220 V (50 Hz) compared to over 200 kΩ at 200 V. The quick transition is labelled 'rupture of skin'. Ok, that figure is only based on 'one living person': a lot else about impedance with substantial voltages is on larger numbers of corpses. But I can verify tripping a 30 mA RCD from contact of a 1.5 mm2 conductor-end (from a cut-off wire, insulated except the 1.5 mm2 tip) on a palm, with 230 V, when the other body connection was a good one; it left a white spot. As long as there are fairly poor contacts at both the 'entry' and 'exit' then the split of 230 V between them prevents this level of skin voltage being achieved.
(Following a recent discussion of units, how should that skin 'resistance' be described? It may be 5 to 50 kilohms for a 1 cm square [for a given voltage and condition], but saying e.g. "50 kΩ per cm2" suggests 500 kΩ for 10 cm2. Instead, writing as 50 kΩ·cm2 would be the strange-sounding way that shouldn't be able to be misunderstood. Alternatively 20 µS/cm2. Yes, I know no one who thinks about the subject would misunderstand anyway...)
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