  We report on experiments conducted on single walled carbon nanotube bundles
aligned in chains and connected through a natural contact barrier. The
dependence upon the temperature of the transport properties is investigated for
samples having different characteristics. Starting from two bundles separated
by one barrier deposited over four contact probes, we extend the study of the
transport properties to samples formed by chains of several bundles. The
systematic analysis of the properties of these aggregates shows the existence
of two conduction regimes in the barrier. We show that an electrical circuit
taking into account serial and parallel combinations of voltages generated at
the junctions between bundles models the samples consistently.
