I am with BobB, unless you have a really good reason not to fit Earth Leakage Protection, why wouldn't you. They can save lives, reduce fire risk and reduce fault currents for Line to Earth failures. Space constraints may have been a problem in the past, but now there a 3 Phase RCBOs available. Not in quite such agreement with RCD types for use with VSDs, the ABB manual allows for Type A with single phase drives, but type B for three phase drives, and the Filters can stay connected. And 'yes' B type RCDs are expensive to 'bl**dy expensive', but as use increases, prices will fall.