RCD Protection?

[wreck-it-steve]

Hi, I am asking this question on behalf of a family member who has a waste tank at his home...

Waste from the house (toilet, sinks etc) are sent to this tank and then two pumps send it up to the main drains on the road. The install is fed via a armoured cable then the two pumps are fed from the control box via SY cable. There is no RCD protection at either end and my question is does it need it?

If so is it best to fit an RCD in the control panel or two RCBO's for the pumps?

Thanks

 

[flameport]

No RCD required.

 

[wreck-it-steve]

No RCD required.

Can I ask why?

 

[flameport]

Circuit does not supply socket outlets or mobile equipment outdoors.
Cables are presumably not concealed in walls or partitions, and are armoured so wouldn't matter even if they were.
Not a location where RCD would be required such as a bathroom, caravan or marina.

The only instance where an RCD would be required is with a TT earth system, which would mean a suitable RCD at the origin to ensure disconnection in the event of a fault to earth. However that has nothing to do with the installation comprising pumps or near/in water.

 

[ericmark]

I would agree with flameport. To fit an RCD could mean the pumps will fail when most needed. There are special protective devices designed for pumps but one of the main requirements is some visual indication should the pump fail.

I would tend to fit a RCM rather than RCD so you have some warning of a fault but it does not auto disconnect.