HT FULLTEST3, User Manual, Page: 55 / 100

FULLTEST3
EN - 53
6.6.2. Prospective short circuit current calculation
LIMIT
mode
TT system
Evaluation condition
TN system
Evaluation condition
L/L
STD No evaluation No evaluation
kA ISC L/L MAX 3PH < BC ISC L/L MAX 3PH < BC
I
2
t
(ISC L/L MAX 3PH)
2
× t < (K × N
× S)
2
(ISC L/L MAX 3PH)
2
× t < (K × N
× S)
2
TRIP
CURR.
ISC L/L MIN 2PH
o
Tmax,
Tmax < Tlim
ISC MIN 2PH
o
Trip time T, T <
Tlim
Ut
L/N
STD No evaluation No evaluation
kA ISC L/L MAX 3PH < BC ISC L/L MAX 3PH < BC
I
2
t
(ISC L/N MAX)
2
× t < (K × N ×
S)
2
(ISC L/N MAX)
2
× t < (K × N × S)
2
TRIP
CURR.
ISC MIN 2PH
o
Trip time T, T <
Tlim
ISC MIN 2PH
o
Trip time T, T <
Tlim
Ut
L/N
STD No evaluation No evaluation
kA ISC MAX L/N < BC ISC MAX L/N < BC
I
2
t
(ISC MAX L/N)
2
× T < (K × N ×
S)
2
(ISC MAX L/N)
2
× T < (K × N ×
S)
2
TRIP
CURR.
ISC MIN L/N
o
Trip time T, T <
Tlim
ISC MIN L/N
o
Trip time T, T <
Tlim
L/PE
STD No evaluation No evaluation
kA ISC MAX L/PE < BC ISC MAX L/PE < BC
I
2
t
(ISC MAX L/PE)
2
× T < (K × N ×
S)
2
(ISC MAX L/PE)
2
× T < (K × N ×
S)
2
TRIP
CURR.
ISC MIN L/PE
o
Trip time T,T<T
lim
ISC MIN L/PE
o
Trip time T, T <
Tlim
Ut ISC MIN L/PE > N × In ISC MIN L/PE > N × In
where:
BC = breaking capacity of the protection
T = Trip out time according to the characteristic and nominal current of used
protection device
K = see the below table
Material/Coating PVC Natural / Butyl rubber EPR/XLPE
Cu (Copper) K = 115 K = 135 K = 143
Al (Aluminum) K = 76 K = 87 K = 94
N = Number of conductors
S = Cross section of a conductor
For calculation of short-circuit current I
SC
nominal voltage Un of mains installation is
needed, so it must be selected in prior to the measurements. How to select the
nominal voltage Un: Press the
MENU
o
SETUP
o
NOMINAL VOL. touch-screen
keys and select the desired value (see § 5.5)
3. Check selected measurement mode (LOOP L/N, LOOP L/L, LOOP L/PE, IMP57
L/N, IMP57 L/L or IMP57 L/PE) and modify it if needed by pressing the MODE
touch-screen key first