(under construction)

Surge ratings

Per IEC 61326-1:2021 "Electrical equipment for measurement, control and laboratory use – EMC requirements", required surge rating for DC ports can vary between N/A to ±1kV line-to-line (2Ω) & ±2kV line-to-ground (12Ω). If DC voltage is limited to ≤60V coming from a 'clean' power source over less than 30m of indoor wiring, then no testing is required, even for the so-called 'industrial electromagnetic environment'.
In our opinion, these devices can easily sit at the end of fairly long cables which share conduits with other mains cabling, or which are installed outdoors. Such gives plenty of opportunity for lightning surges to couple into our low-voltage signals... The higher rating have the additional benefit that surge endurance is almost infinite at the 'mandatory' surge voltages. That's because protective components such as gas discharge tubes and metal oxide varistors have a finite energy handling capability. Every absorbed surge does a bit of permanent damage; big surge, big damage, small surge, small damage. And in order to pass an EMC test, the protective components have to survive only 10 surges at the highest applicable level. The varistor in our 6kV-rated devices can handle about 15 strikes at 6kV/3kA and this increases to almost 10k strikes at the more reasonable 1kV/500A surge. A device designed for the latter can pass EMC by handling only 15 strikes.

Pulse, voltage & impedance:Specifiation:Requirement:
DC input to ground1.2/50µs ±6kV 2ΩPASS, B
DC input to earth1.2/50µs ±6kV 12ΩPASS, B
Ground to earth1.2/50µs ±6kV 12ΩPASS, B
Shield to earth1.2/50µs ±6kV 12ΩPASS, B
Grounds across isolation1.2/50µs ±6kV 12ΩPASS, B
Communications port transverse H/L1.2/50µs ±6kV 2ΩPASS, B
Communications port transverse H/L/ground/earth1.2/50µs ±6kV 12ΩPASS, B
Communications port CM to ground10/700µs ±6kV 15+25ΩPASS, B

Other standard tests

Description:Standard:Specifiation:Requirement:
ESDIEC 61000-4-2:2009±8kV contact, ±15kV airPASS, B
Radiated immunityIEC 61000-4-3:202010V/mPASS, A
EFT/BurstIEC 61000-4-4:2012±4kV 5kHz and 100kHzPASS, B
Conducted immunityIEC 61000-4-6:2014140dBµVPASS, A
Conducted immunity LFIEC 61000-4-16:2016Level 3; between 1 and 10Vrms up to 150kHzPASS, A
Ripple on DC inputsIEC 61000-17:200215% on VIN,MIN and VIN,MAXPASS, A
Dips & interruptionsIEC 61000-29:2002Performance A up to 10ms, performance B for >10msPASS, A/B 1)

Custom tests

These tests primarily concern with wiring errors during installation.

Description:Specifiation:Requirement:
DC reverse polarity−VIN,MAX: 15minPASS, B
DC overvoltageVIN,MAX+20%: 15minPASS, A
DC overvoltageVIN,MAX+50%: 15minPASS, C 2)
AC powerVRMS ≤ VIN,MAX: 15minPASS, B
AC mains voltage230VRMS 50Hz 40Ω: 15minPASS, D 3)
DC voltage to communications ports, CM and DM120% VIN,MAX: 15minPASS, B
AC mains voltage to communications ports, CM and DM230VRMS 50Hz 40Ω: 15minPASS, D 3)

1) Some devices may have backup power option in order to survive much longer voltage interruptions.
2) Serious overvoltages will trip a thermal cut-out or blow the (socketed) fuse inside the device.
3) This test is about product safety; whatever the failure mode, it must be contained.

6kV Surge rated