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Omitting 30ma RCD Protection for single S/O in a domestic property

Former Community Member
Former Community Member
I installed a dedicated circuit for a hifi system for a customer last year. The customer requested a 6mm2 radial from a 16A MCB housed in its own independent consumer unit into a single, un-switched socket outlet. No problem, bit unusual but no worries.I wired it using a 3c 6mm2 armoured cable as I half anticipated the forthcoming...


The hifi equipment is causing the rcd to trip when started up. I haven't been over to have a look but I am assuming that the startup current for the many power supplies (he has told me there are ten!) coupled with electronic earth leakage is causing a CPC current that is sufficient to trip the RCD (perhaps only 16ma but enough). The earthing is high integrity having a 6mm2 cpc + armour and the Zs is sufficiently low enough that the 16A MCB can be used for fault protection. So, if this wasn't domestic I'd ditch the RCD (or replace with a 100ma) assuming that my assumptions to this point are correct.


The customer has now decided he doesn't want RCD anyway for 'reasons' but I'm still wary of removing it in a domestic situation, not because I believe the installation would become less-safe but just because it contravenes regulations.


Assuming there's no fault on the equipment and it is just a case of startup/inrush current and earth leakage, what approach would you take? Remove the RCD and write it up as a deviation from 7671 with a signed disclaimer/waiver from the customer? Install a 100ma RCD? Do nothing and walk away? Something else?


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    Agreed, I would fit a number of socket outlets each of which incorporates its own RCD. No need for RCD protection to the circuit if in SWA, provided that each socket includes an RCD.

    With the starting inrush and earth leakage spread over several RCDs tripping seems unlikely unless there is a significant and potentially dangerous fault on the hi fi equipment.
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    Agreed, I would fit a number of socket outlets each of which incorporates its own RCD. No need for RCD protection to the circuit if in SWA, provided that each socket includes an RCD.

    With the starting inrush and earth leakage spread over several RCDs tripping seems unlikely unless there is a significant and potentially dangerous fault on the hi fi equipment.
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