Had a look at a job the other day, client has brought a MK RCD Garage CU and wants it connected up.
Supply is TNC-S with a 100mA RCCB protecting a BS1361 fuse board which has MCB's
Option 1. Replace the RCCB with a time delayed RCD and connect garage CU to new RCD
Option 2. Henley block the meter tails and connect both CU's to Henley block so both RCD's are in parallel
All wiring will be surface mounted SWA.
Both methods would achieve discrimination, which method would be the preferred one?
Thanks
Supply is TNC-S with a 100mA RCCB protecting a BS1361 fuse board which has MCB's
Option 1. Replace the RCCB with a time delayed RCD and connect garage CU to new RCD
Option 2. Henley block the meter tails and connect both CU's to Henley block so both RCD's are in parallel
All wiring will be surface mounted SWA.
Both methods would achieve discrimination, which method would be the preferred one?
Thanks