I just placed a new defense outpost, running a line of big electric poles and placing down a blueprint. Don't have robots yet, so I need to place everything manually.

I manually place the transformer, fill the small pole places, and boom .. both small poles explode, short after placing them - first the one I placed second, after maybe one second, and then that one I placed first. Both because they overloaded, for 21 MW - but the transformer was not wired up yet and the small poles were not connected to the big pole. This/similar behaviour I had a couple of times, but this time I am really sure there was no juice on the poles that exploded.

If it matters: I'm also using the mod "Get Wires back" with the setting for handling copper cables active.