If I build my sukkah underneath electric wires, is the sukkah kosher? Can I sit in the part of the sukkah that's underneath the wires?
Per the second from the right, second from the top cartoon on this "Hilchot Sukka 2" poster, a similar case involving clotheslines is fine, even if there are multiple lines running near each other (though there are those who are stringent about it).
סוכה שנעשית תחת חבלי כביסה, או חוטי חשמל וטלפון, אפילו אין בין חבל לחבל שלשה טפחים, אין לפסול מטעם לבוד, אלא הסוכה כשרה. ואפילו אם תלו כביסה על החבלים אין בכך כלום והסוכה כשרה.
A sukkah that is built under clothes lines, or electric or telephone wires, even if there are less than three tefachim between adjacent wires, does not pasul the sukkah because of lavud, rather the sukkah is kosher. Even of you hang clothes from the clothes lines, this is not a problem, and the sukkah is still kosher.
If there are multiple lines which are within three tefachim of each other, they are considered to be a closed solid area of schach pasul, which could then theoretically disqualify your sukka, depending on where it is situated above your sukka