Voltage

[martysparky]

Can anyone state a reg that gives the voltage between L and N of cables if a short circuit occurs in a LV system?

Ta

 

[davelerave]

what do you mean- a reg?

 

[Darkwood]

Its the current that surges during short circuit the voltage may drop or spike within the same network due to the short circuit but knowing this has too many variables so i cant see why you are trying to source this info'

 

[nick611]

do you mean current flow? that,s ohm,s law

 

[martysparky]

Re: Voltage question help please

Can anyone state a reg that gives the voltage between L and N of cables if a short circuit occurs in a LV system?

Ta

oops I should have said where will I find info in the regs about this maybe. Got me dull ed on lol

I'm looking to find the increase in voltage value between L and N in other conductors during a short circuit.

Its my understanding that its 1.45 x U0 but where to find that in the regs for reference fails me.

Any guidance on this will be appreciated.

 

[ezzzekiel]

1.45 refers to overload time charachteristics of breaker and 5x would be instantaneous operation of the breaker (for a type b)

if you 5x the breaker rating and divide by the voltage you will get max zs divide this by the voltage and you will get the max fault current that can flow

 

[IQ Electrical]

Re: Voltage question help please

oops I should have said where will I find info in the regs about this maybe. Got me dull ed on lol

I'm looking to find the increase in voltage value between L and N in other conductors during a short circuit.

Its my understanding that its 1.45 x U0 but where to find that in the regs for reference fails me.

Any guidance on this will be appreciated.

I'm with you now, try 442.3 442.4 and 442.5.

It should be noted that if a short circuit occurs in a LV installation between a line and neutral conductor, the voltage between the other line conductors and the neutral conductor can reach up to 1.45 Uo for up to 5 seconds.