If you use more than the LV transformer can output per tick, which is 32eu/t, then yes, that will cause an issue. More LV transformers would fix that, and after a bit of time, more MV transformers.
Electro furnaces only need, when not overclocked/etc, 32eu/t to run, so that should not be an issue in that regard. Make an EU-meter to check out EU is flowing through your system, though, to get a better idea.
I did a bit of testing and it seems that the LV transformer thing doesn't matter. The test: I put in 8 cobblestone blocks in each of 7 furnaces. Then I put 8 cobblestone into the last furnace and timed it. It took 37 seconds (with one overclocker). Since 8 furnaces working at once takes 256 EU/t, that should be more than the LV transformer is capable of handling.
So I did a second run. This time I connected one furnace to a separate LV transformer, the other 7 to the same transformer they were connected to before. With a separate transformer, this lone furnace shouldn't be effected by the other furnaces. Did the same test, 8 cobblestone in each furnace. It still took 37 seconds to smelt 8 cobblestone.
Careful guys, you're mixing up some things.
As Guswut said when he explained the geothermal generators, IC2's power network works by packet size. This is true for
all IC2 machines, not only generators. When the electric furnace says that it accepts up to 32 EU/t, that means it can take
packets of up to 32 EU in size (i.e. low 'voltage'). However, this has nothing whatsoever to do with the actual energy consumption of the device; it's only for 'voltage' compatibility. An electric furnace consumes 3 EU/t without overclockers installed.
The way this works is as follows: The furnace consumes 3 EU on tick 1, and then sends a request to the energy network, saying "I need 3 EU". All devices capable of sending energy then consider that request and check if they can fulfill it. In your case, the LV-transformer is the sole recipient. It says, "I can send packets sized 32 EU, and this request asks for 3. I cannot fulfill it." And therefore it does nothing.
The furnace continues working, consuming 3 EU and sending a new request every tick. It will ask for 6 EU, then 9 EU, then 12 EU and so on, always naming the number that is missing in its internal buffer. After a total of 11 ticks have elapsed, the furnace asks for 33 EU. The LV transformer then says, "hey, I can do that!" and sends a packet of 32 EU to the furnace, restoring its internal buffer by that much. It's not the exact amount that was requested, but the important part is that the furnace asks for
at least as much as the packet size the transformer can output. If you had hooked up the geothermal directly, it would have supplied a 20 EU packet after 7 ticks, when the furnace asked for 21.
The LV-transformer then turns around to its own input side network and says "I need 32 EU", because well, it just sent out 32 and needs to replace them. The next device in line is the MV-transformer. It receives the request for 32 EU, but says "I can only do packets sized 128" and does nothing. It will wait until the LV-transformer has sent out three more packets of 32 EU, and at which point the MV-transformer supplies one packet of 128. Then it turns around to it own input side network and says "I need 128 EU". But the MFSU next in line can only provide 512, so it waits, and so on and so forth...
Hope that clears up things a bit
(For reference, the internal buffer of a tier 1 machine, like the electric furnace, is 800 EU. The internal buffer of a transformer is equal to its maximum safe input - i.e. 128 for a LV, 512 for a MV, and 2048 for a HV transformer. That is also the reason why a transformer can only step down one large packet into 4 smaller ones per tick - because then its internal buffer is empty and it needs to request a new large packet on the transition to the next tick.)
