General characteristics

[Spoon]

If a fault occurs in the HV system and a magnitude of fault voltage of 430v occurs between exposed conductive parts and earth on the LV installation, what is the maximum tolerable duration of the fault

Have a look at Reg 442.2.2 mate

 

[rich3009]

25) If a fault occurs in the HV system and a magnitude of fault voltage of 430v occurs between exposed conductive parts and earth on the LV installation, what is the maximum tolerable duration of the fault
a) 10ms
b) 100ms
c) 200ms
d) 300ms

I don't know how to answer this one

 

[westward10]

What needs to happen generally under fault conditions, disconnection (ADS). You are looking for disconnection times.

 

[rich3009]

Do you know the answer and how it's derived

 

[westward10]

Have you not tried looking up disconnection times.

 

[rich3009]

Doesn't help

 

[westward10]

411.3.2

 

[rich3009]

Is it 10ms based on greater than 400v on a TN system and tolerated as in human heart, I thought it was cable fire. duh

 

[rich3009]

Or is 0.1s 100ms in real money crap at decimal conversion