Does a Digital Shower Mixer Valve require an RCD ?

[Greycom]

Im considering installing a Digital Shower (not pumped, just controlled) during my Bathroom Refit. Im looking for the best option for powering the valve. The Manufacturer recommends runnig a 30mA RCD circuit, however as my Sockets are already protected with an RCD can I connect the valve into a 3 Amp fused spur ? or should I go with the separate RCD circuit, thanks.

 

[Dartlec]

If your sockets are already protected by an RCD, then yes in theory it's acceptable to spur from that circuit with the appropriate fused spur to use the existing RCD protection.

There are possibly some caveats to consider:

1. If this is in a bathroom it may be notifiable under Part P of the building regulations, so may need a registered competent person to install/notify.
2. Modern equipment often has electronics in, which don't always play nicely with the older type of RCDs commonly fitted in most houses (Type AC). There may be some safety benefits to installing it on a circuit protected by a Type A RCD.
3. Adding it to the socket circuit does mean that any trip will also isolate sockets and any other circuits on that RCD. If you are doing refurbishment and having other electrical work done, there may be some benefit to having it run on it's own separate RCBO circuit, which means it will not affect any other circuits in the event of it tripping.

Does the manufacturer specify the type of RCD protection required?

 

[Greycom]

If your sockets are already protected by an RCD, then yes in theory it's acceptable to spur from that circuit with the appropriate fused spur to use the existing RCD protection.

There are possibly some caveats to consider:

1. If this is in a bathroom it may be notifiable under Part P of the building regulations, so may need a registered competent person to install/notify.
2. Modern equipment often has electronics in, which don't always play nicely with the older type of RCDs commonly fitted in most houses (Type AC). There may be some safety benefits to installing it on a circuit protected by a Type A RCD.
3. Adding it to the socket circuit does mean that any trip will also isolate sockets and any other circuits on that RCD. If you are doing refurbishment and having other electrical work done, there may be some benefit to having it run on it's own separate RCBO circuit, which means it will not affect any other circuits in the event of it tripping.

Does the manufacturer specify the type of RCD protection required?

Thanks Dartlec for your points, I've just picked the shower up and the fitting instructions say......
"A separate perminently connected supply must be taken from the the ring main to the appliance through a 3 Amp double pole switched fused spur providing a minimum 3mm contact gap in each pole. Im sure I did read on;ine that a
50 mA RCD was required but it didnt specify further details. Currently my sockets are protected by a CrabtreeSplitload RCCB (80 A 30mA). Would still like to use the lighting circuit with a secondary RCD at the CU,

 

[Dartlec]

Thanks Dartlec for your points, I've just picked the shower up and the fitting instructions say......
"A separate perminently connected supply must be taken from the the ring main to the appliance through a 3 Amp double pole switched fused spur providing a minimum 3mm contact gap in each pole. Im sure I did read on;ine that a
50 mA RCD was required but it didnt specify further details. Currently my sockets are protected by a CrabtreeSplitload RCCB (80 A 30mA). Would still like to use the lighting circuit with a secondary RCD at the CU,

It wouldn't be good practise to run a load like that from a lighting circuit to be honest.

Manufacturers instructions are meant to be followed, but those sound badly worded and clearly not written by an electrician (It's a Ring Final Circuit, not a ring main, for example).

It sounds like your best bet would be to run it from a fuse spur on the socket circuit. Or to avoid the potential tripping issues and if you are happy to get an electrician to do the work, run a separate RCBO protected circuit from the consumer unit to the location of the shower (still include an isolation switch at a suitable point near the shower, but outside the bathroom).

RCDs in the UK are all 30mA for this sort of application, whichever you do.

 

[Greycom]

It wouldn't be good practise to run a load like that from a lighting circuit to be honest.

Manufacturers instructions are meant to be followed, but those sound badly worded and clearly not written by an electrician (It's a Ring Final Circuit, not a ring main, for example).

It sounds like your best bet would be to run it from a fuse spur on the socket circuit. Or to avoid the potential tripping issues and if you are happy to get an electrician to do the work, run a separate RCBO protected circuit from the consumer unit to the location of the shower (still include an isolation switch at a suitable point near the shower, but outside the bathroom).

RCDs in the UK are all 30mA for this sort of application, whichever you do.

Thanks Datrlec for the detailed reply. I've requested an electrician to come and run a separate RCBO protected cirbuit from the consumer unit. Really appreciate taking the time to reply to my post.