The 1664 FC puts more power in your hands by quickly and efficiently testing to all local regulations, protecting appliances that may be inadvertently connected to the system under test, and making it easy to share test results over your smartphone.

• Autotest to test line/loop impedance, RCD trip current / trip time, insulation tests with a single connection and the press of a single button.
• Additional high current loop mode. Faster measurements compared to loop tests with non-trip mode for RCDs.
• Z-max memory for loop tests – easy evaluation of the highest loop test value.
• Unique zero adapter for fast, always reliable and accurate test lead and mains cord compensation.
• Fast voltage measurement between L-N, L-PE and N-PE using the mains cord. No need to change measurement connections.
• Measure RCD trip current & trip time in parallel (RCD type AC and A).
• Two measurements at once and a dual display. PEFC or PSC and loop impedance are measured and displayed in parallel, saving you time.
• Ring testing – select the required input sockets with soft keys – no need to exchange test leads.
• Automatic test start for Loop & RCD tests – as soon as mains voltage is stable it starts testing.
• Earth Volt Touchpad detects raised earth voltages >50 V, indicating potential dangerous situations.
• Supplied with the safety designed SureGrip™ test leads and clips which gives the user a comfortable, reliable grip and consistent results.
• Rotary dial knob indicates clearly which function is selected, all in one spot with no complex multi-level menus.
• Large display with backlight, clear symbols and with exceptionally wide viewing angle for easy and safe readings.
• PASS/FAIL indication for RCD test results.
• Variable RCD current mode for customized settings.
• Loop & line resistance with mΩ resolution.
• Test smooth dc sensitive RCDs (Type B).
• Extended memory with 3 layers.
• Use continuity test currents to measure motor windings.
• Withstands a drop of 1 meter.
• Compact, lightweight (less than 1.3 kg) and padded neck-strap to free your hands for all day testing.

AC voltage measurement
Range	500 V
Resolution	0.1 V
Accuracy 45 Hz – 66 Hz	0.8% + 3
Input impedance	360 kΩ
Overload protection	660 V rms
Continuity testing (RLO)
Range (autoranging)	20 Ω / 200 Ω / 2000 Ω
Resolution	0.01 Ω / 0.1 Ω / 1 Ω
Open Circuit Voltage	>4 V
Insulation resistance measurement (RISO)
Test voltages	50-100-250-500-1000 V
Accuracy of tTest voltage (at rated test current)	+10%, -0%
Test voltage	50 V 100 V 250 V 500 V 1000 V
Insulation resistance range	20 MΩ /50 MΩ 20 MΩ / 100 MΩ 20 MΩ / 200 MΩ 20 MΩ / 200 MΩ / 500 MΩ 20 MΩ / 200 MΩ / 1000 MΩ
Resolution	0.01 MΩ / 0.1 MΩ 0.01 MΩ / 0.1 MΩ 0.01 MΩ / 0.1 MΩ 0.01 MΩ / 0.1 MΩ / 1 MΩ 0.01 MΩ / 0.1 MΩ / 1 MΩ
Test current	1 mA @ 50 kΩ 1 mA @ 100 kΩ 1 mA @ 250 kΩ 1 mA @ 500 kΩ 1 mA @ 1 MΩ
Loop and line impedance (ZI)
Range	10 Ω / 0.001 Ω / High current mΩ mode
Resolution	0.01 Ω / 0.1 Ω / 1 Ω
Prospective earth fault current, PSC test
Range	1000 A / 10 kA (50 kA)
Resolution	1 A / 0.1 kA
Computation	Prospective earth fault current (PEFC) or Prospective short circuit current (PSC) determined by dividing measured mains voltage by measured loop (L-PE) resistance or line (L-N) resistance, respectively.
RCD testing, RCD types tested
RCD Type	AC¹ G²,S³
Model 1664	A, AC, B5, S
Notes	¹Responds to AC  ²General, no delay ³Time delay 4Responds to pulsed signal 5Responds to smooth DC signal
Tripping speed test (ΔT)
Current settings¹	10-30-100-300-500-1000 mA – VAR 10-30-100 mA
Multiplier	x ½, x 1 x 5
Measurement range	RCD Type G	310 ms 50 ms
	RCD Type S	510 ms 160 ms
Notes	¹1000 mA type AC only 700 mA maximum type A in VAR mode VAR mode not available for type B.
RCD/FI-Tripping Current Measurement/Ramp Test (IΔN)
Current range	30% to 110% of RCD rated current¹
Step size	10% of IΔN²
Dwell time	Type G	300 ms/step
	Type S	500 ms/step
Measurement accuracy	±5%
Specified trip current ranges (EN 61008-1)	50% to 100% for Type AC 35% to 140% for Type A (>10 mA) 35% to 200% for Type A (≤10 mA) 50% to 200% for Type B ²5% for Type B
Notes	¹30% to 150% for Type A IΔN > 10 mA 30% to 210% for Type A IΔN = 10 mA 20% to 210% for Type B
Earth Resistance Test (RE)
Range	200 Ω / 2000 Ω
Resolution	0.1 Ω / 1Ω
Frequency	128 Hz
Output Voltage	25 V
Phase Sequence Indication
Icon	Phase Sequence indicator is active.
General Specifications
Size (L x W x H)	10 x 25 x 12.5 cm
Weight (incl. batteries)	1.3 Kg
Battery size, quantity	Type AA, 6 ea.
Sealing	IP-40
Safety	Complies with EN61010-1 Ed 2.0 (2001-02), UL61010, ANSI/ISA –s82.02.01 2000 and CAN/CSA c22.2 No. 1010 2nd edition
Overvoltage	CAT III / 500V; CAT IV 300V
Performance	EN61557-1 to EN61557-7 Second Edition and EN61557-10 Second Edition