For ground burial: Make all connections in T9969 underground joint kit or similar resin-sealed joint. (Boxes with silicon-sealed lids do not protect against ingress of moisture through condensation and capillary action: ordinary silicon sealant does not bond reliably with all enclosure materials.) After burying the transformer and associated junction boxes, lay a paving slab or similar protective material over it, cover with cable warning tape and back-fill hole. NB: Where multiple ground burial transformers are to be installed in an area, allow connection points where possible above ground to allow for isolation in the event of future fault-finding. Connection of transformers to separate cores of a multicore cable may also be considered. Failure to adopt these recommendations may mean difficulty in fault diagnosis in the future and in extending or upgrading the system.