27-11-2015, 02:49 AM
The cascaded RCDs should be OK. On our mooring site because of the way the power is split through the farm we have up to 4 RCDs of various current and trip current ratings from 100A, 500mA trip to 16A 30mA trip in cascade.
There are occasions when the higher rated RCD will trip when the littluns don't. But it is still a safe instillation. There is literally hundreds of yards of SWA buried.
We have multiple earth rods on the ends of the distribution to the boats to try to ensure that hull corrosion due to galvanic action is minimised, every connection is RCDed separately, we have an awful lot of switch boxes!
If you have problems with bedrock, you can drive earth rods in at an angle, it is the contact area and soil condition that matters. Under a rainwater spout is a great place!
There are occasions when the higher rated RCD will trip when the littluns don't. But it is still a safe instillation. There is literally hundreds of yards of SWA buried.
We have multiple earth rods on the ends of the distribution to the boats to try to ensure that hull corrosion due to galvanic action is minimised, every connection is RCDed separately, we have an awful lot of switch boxes!
If you have problems with bedrock, you can drive earth rods in at an angle, it is the contact area and soil condition that matters. Under a rainwater spout is a great place!
Boater Sam.
