Hi Cookiemonster,
Type B RCDs need to be matched to the inverter wherever possible - to make sure that the leakage currents at certain frequencies are matched correctly to the RCD device used. There are 3 different types of Type B RCD depending on the nature of the installation and inverter characteristics. What we would normally ask is for details of the inverter leakage current at Fmax (Hz) and also the frequency at which the maximum leakage current occurs.
If such info is not available then we would quote for the "NK" range by default (although the most expensive) to make sure that all potential tripping thresholds, frequencies and fire-protection factors are covered. Models are available from 16A to 125A ratings, 2 & 4 pole, 30mA-500mA and are 4-module width as standard across the range.
So, to answer your question, it depends on the RCD solution required. As a brief summary, see below:
Type SK - protection for installations for which fire protection is not mandatory
Type B+ - fire protection for installations up to max. 20kHz
Type NK - the most reliable fire protection with high frequencies. Ideal for work premises subject to fire hazard
Email me directly for more info if required (
[email protected]) and check out Doepke's production selection info here
'B' Type RCDs for more details. I will be loading up some additional useful info to our website before the end of this week.
Regards
Andy
