Board Thread:Questions and Answers/@comment-50.50.188.160-20140701195500/@comment-91.114.133.136-20140710204907

I think this happens because a MFSU can only in- and output 512 EU/t. Because you have EV, the MFSU can't handle it and the cable explodes.

Try to let the reactor power a mass fabricator and look if it still happens.