When the current is getting very high, the link between the transformer and the watercooled cables is made with a bustube, also called delta connection.

The tubes are in electrolytic copper and a water circuit goes through it. 

Connections at the end are made with welded plates in desoxygenized copper. In some cases, plates mechanically fixed by ring terminal lugs can also be used.

Bustubes are also used as a link between watercooled cables and electrode clamps.