It is always the case that a RCD/RCCB/RCBO provides protection only for the downstream system.fitting an upfront RCCB, rather than relying on a main switch, and I liked that thinking as it afforded protection from loose tails as well as from busbar links in a split load board.
Some folk have argues that in the TT case a non-metallic CU enclosure is safer as loose tails (or lack of entrance grommet), busbar going astray, etc, making contact with the case that are upstream of the incoming RCD do not make the system's CPC live. That may be true, but I suspect that of all the serious CU installation faults you might have a partial contact leading to a fire risk is a bit more likely!
But I still think no single point of failure (at least for things depending on electronics - my own background!) is a good goal for safety-critical systems.
[automerge]1597519566[/automerge]
Folk have different reasons, different customer bases, etc.It was this point which set the discussion off in a bit of a spiral. The member in question had expressed a preference for split load boards 'every time' and I tried to ask why when RCBOs are now available at quite reasonable prices. I could see why a relatively small price difference may be too much for some customers, but felt that others might be happy to pay a little extra to minimise potential disruption.
- Some say they will only do RCBO boards as they feel it is the best solution - that is technically valid and saves a bit of fault-finding time in the future
- Others do dual-RCD only - most customers will always choose the cheaper option and doing the installation properly is more important than the specifics of what is chosen
Last edited: