Hi all,

there has been a thread in alt.engineering.electrical and other groups the last week which has annoyed me. I gave me the idea to debunk a bunch of myths regarding other wiring in other countries.

(We'll leave out the ring/radial this time)

For starters we could start with these ideas. Please comment and add your own questions!

110-120V vs. 220-240V

Pro 120V

"1. The risk of electrocution is significantly lower at 110-120V than at 220-240V."

True.

"2. The voltage is the most important factor when determining the risks with electricity"

No true? Other factors, such as workmanship, protective devices and quality of devices are more important?

Pro 240V

"1. Fire risk is far more important than shock risk. More people die from electrical fires than from electrocution."

True or not?

"2. Currents are lower for the same power, leading to less cable heating and reduced fire risk."

True, but is it significant?

"3. As currents are lower, protective device ratings may be lower."

Only true in theory. In practice, protective devices from 10A to 20A are used on both systems.

"4. Arcing risk. As the voltage is higher, the prospective fault current is higher, making the protective device more likely to trip during a fault."

True?

"5. Users of 110-120V systems believe them to be safer so don't take precautions
against shock, unlike users of 220V-240V systems."

No opinion. Your input?

"6. The lower insulation requirements lead to nasty cheap low quality wiring
accessories"

Not true. The voltages are too low to influence the insulation requirements. In fact, the insulation of the devices are tested with thousands not hundreds of volts.

-------------
I've got a whole bunch of these not related to voltage level but I'll take those some other day.