Thermal Expansion bug?

[Tassyr]

So I've got a reactor setup under my base- way under. The idea was to set up the reactors safely enough away that if -anything- borked up the base would survive on battery power. But when I exited the underground bit and did a test, I ran into a rather disturbing problem.

 

 

I'm losing about 15% of all my power generated simply by trying to run through ONE seal wire? JUST ONE? 

 

The 8571 is on the right, the 10000 on the left. I thought TE was supposed to be lossless- how do I get around this? Is there an alternative? Something I can configure?