SEW 8025LP LOOP & PSC TESTER

SEW 8025LP Earth fault loop impedance testing

Earth fault loop impedance is the path followed by fault current when a low impedance fault occurs between the phase conductor and earth, i.e. “earth fault loop”. Fault current is driven round the loop by the supply voltage. The higher the impedance, the lower the fault current will be and the longer it will take for the circuit protection to operate.

To make sure the protection operates fast enough, the loop impedance must be low. Every circuit must be tested to make sure that the actual loop impedance does not exceed that specified for the protective device concerned.

Prospective short circuit current (PSC) testing

The prospective short circuit or fault current at any point in an electrical installation is the current that would flow in the circuit if no circuit protection operated and a complete (very low impedance) short circuit occurred. The value of this fault current is determined by the supply voltage and the impedance of the path taken by the fault current. Measurement of PSC can be used to check that protective devices within the system will operate within safety limits and as per the safe design of the installation. PSC is normally measured between the phase and neutral.

The TNT-EL mains lead supplied with SEW 8025LP

SEW 8025LP Specifications:

Loop Impedance
Range	Measuring range	Nominal test current at 0 Ω external loop	Accuracy
20 Ω	0.00~19.99 Ω	23A / 40ms	(2%rdg + 4dgt)
200 Ω	0.0~199.9 Ω	2.3A / 40ms
2000 Ω	0~1999 Ω	15mA / 400ms
Prospective Short-circuit Current
Range	Measuring range	Nominal test current at 0 Ω external loop	Accuracy
20 KA	0.00~4.00 KA	23A / 40ms	Consider accuracy of loop impedance
2000 A	0~1999 A	23A / 40ms
200 A	0.0~199.9 A	2.3A / 40ms
Voltage Display
Measuring range	Accuracy	Remark
150~260 V	(2%rdg + 4dgt)	at 0 Ω external loop
General
Temperature	0 ~ 40 °C
System voltage	230V	+13%
		-15%
System frequency	50Hz
None Battery system voltage	150V ~ 260V
Over Temperature Protection	When overheating,the ”  ”  symbol will show on the LCD, and the 8025LP stop measuring.
Wiring check	P-E	LEDs illuminate when the wiring polarity of circuit under test is correct
	P-N
	N-E	LED is light when P and N are reversed or the Earth is not connected.
15mA Loop measurement	Loop impedance 2000Ω range measurement is carried out with low test current (15mA). The current will not cause tripping out for ELCBs.