NEC ECC: Who carries the risk when a subcontractor goes into administration

If an accepted sub-contractor is supplying & installing bespoke plant and goes into administration before their element of the works are complete, it is my understanding that this is not an Employer’s risk and therefore the cost of replacing this equipment with a suitable alternative is borne by the Contractor. Is this correct?

It would depend on the main Option. Under Option A this is a Contractor’s risk however under Option C it would be a shared risk. There are circumstances in Option C where the PM may disallow certain costs which would shift the risk back onto the Contractor.