When using conductive thread in a sewing machine choose a needle with a large eye so the thread will flow smoothly and not fray.
I use a Schmetz 90/14 embroidery needle on both my industrial machine as well as my Bernina 180.
For hand sewing conductive thread my favorite needle is a John James Chenille size 24. The eye of the needle is elongated allowing a variety of threads to be easily threaded. This needle is also thin enough to fit thru the standard mounting hole for most electronic hardware.
Before you begin your project test different needles with your choice of conductive thread and hardware. The weight (diameter) of the thread, the fabric, and the hardware’s attachment hole will all impact your needle selection.