Circuit protection for older cables ( VIR & cotton covered ect )

9 February 2024

The Technical Team has received a number of enquiries regarding the correct circuit breaker size for the older VIR, TRS or single insulated PVC cable. If this type of cabling is found it must be reported to the owner and the network operator. 

When completing a switchboard upgrade and the cabling is found to be in serviceable condition, the circuit breaker size needs to be selected as per Table I1 of AS/NZS 3000:2018 (below).