Abstract We demonstrate that the inter-edge-channel scattering of a two-dimensional electron gas in the quantum Hall regime can be dramatically suppressed when the confining potential at the boundaries of the sample is altered. The confining potential is changed by making use of a half-gated GaAs/AlGaAs heterostructure. This results in a large spatial separation of the respective edge channels. We use an interior contact to detect or feed the separated edge channels. Due to the large spatial separation, it is shown that the equilibration length becomes arbitrarily long, even at a relatively high temperature of 1.2 K.