  We analyze the scaling of the crack roughness and of avalanche precursors in
the two dimensional random fuse model by numerical simulations, employing large
system sizes and extensive sample averaging. We find that the crack roughness
exhibits anomalous scaling, as recently observed in experiments. The roughness
exponents ($\zeta$, $\zeta_{loc}$) and the global width distributions are found
to be universal with respect to the lattice geometry. Failure is preceded by
avalanche precursors whose distribution follows a power law up to a cutoff
size. While the characteristic avalanche size scales as $s_0 \sim L^D$, with a
universal fractal dimension $D$, the distribution exponent $\tau$ differs
slightly for triangular and diamond lattices and, in both cases, it is larger
than the mean-field (fiber bundle) value $\tau=5/2$.
