Restaurant Kitchen & 3-Phase Oven RCDs

By "bayonet sockets" do you mean something that is only used as part of the oven itself, or a general purpose thing, where later someone could wheel in another 3 phase load and plug it in ?


(BS 7671 stops at the fixed wiring - connectors within an applience or rack are normally covered by product standards - same as you can have live parts exposed inside yuor washing machine, you could have a connector non RCD protected inside a closed box needing a tool to undo.)


The general intention in the current regs is that pretty much anything that is not bolted to the floor needs an RCD, unless there is a very good reason otherwise, though I am aware of 63 A sockets being pressed into service simply to avoid just this rule, that is not normally the best solution.

If fed by SWA or in metal conduit, the RCD could be beside the oven which may or may not help the pain if it trips off unexpectedly, no need to have it in a cupboard miles away.


You could see if there reasonable are grounds for ignoring this - devices that simply have to much earth leakage by design for example, but then there is a need to mitigate the fact that the equipment is single fault to danger if the CPC is broken,  (as the case will be capable of delivering a lethal shock with no second fault needed, as opposed to the normal case where a CPC fault and a live wire inside touching the case gives double fault to danger) In some cases like high leakage equipment, the double fault to danger or better may be restored by having a supplementary CPC paths for example.


Do the oven maker's instructions say that it is or is not OK with a 30mA RCD - maybe do they have a helpline to ask ?

Assume you will need one, until you can show otherwise.

By "bayonet sockets" do you mean something that is only used as part of the oven itself, or a general purpose thing, where later someone could wheel in another 3 phase load and plug it in ?


(BS 7671 stops at the fixed wiring - connectors within an applience or rack are normally covered by product standards - same as you can have live parts exposed inside yuor washing machine, you could have a connector non RCD protected inside a closed box needing a tool to undo.)


The general intention in the current regs is that pretty much anything that is not bolted to the floor needs an RCD, unless there is a very good reason otherwise, though I am aware of 63 A sockets being pressed into service simply to avoid just this rule, that is not normally the best solution.

If fed by SWA or in metal conduit, the RCD could be beside the oven which may or may not help the pain if it trips off unexpectedly, no need to have it in a cupboard miles away.


You could see if there reasonable are grounds for ignoring this - devices that simply have to much earth leakage by design for example, but then there is a need to mitigate the fact that the equipment is single fault to danger if the CPC is broken,  (as the case will be capable of delivering a lethal shock with no second fault needed, as opposed to the normal case where a CPC fault and a live wire inside touching the case gives double fault to danger) In some cases like high leakage equipment, the double fault to danger or better may be restored by having a supplementary CPC paths for example.


Do the oven maker's instructions say that it is or is not OK with a 30mA RCD - maybe do they have a helpline to ask ?

Assume you will need one, until you can show otherwise.