  Two compact universal extra dimensional models are an interesting class of
models for different theoretical and phenomenological issues, such as the
justification of having three standard model fermion families, suppression of
proton decay rate, dark matter parity from relics of the 6-dimensional Lorentz
symmetry, origin of masses and mixings in the standard model. However, these
theories are merely effective ones, with typically a reduced range of validity
in their energy scale. We explore two limiting cases of the three standard
model generations all propagating in the bulk or all localised to a brane, from
the point of view of renormalisation group equation evolutions for the Higgs
sector and for the neutrino sector of these models. The recent experimental
results of the Higgs boson from the LHC allow, in some scenarios, stronger
constraints on the cut-off scale to be placed, from the requirement of the
stability of the Higgs potential.
