It's definitely a sewer tape or snake for drain lines (through clean outs in the sewer pipes, not through the toilet stool). Used one many times and had a couple in the hardware store to rent out. Very heavy tool with a cutter on the end for cutting roots in the line. I can't imagine trying to use it for an electrician's tape, way too heavy and stiff.
One for sale on Amazon:
http://www.amazon.com/Cobra-Products-61000-4-Inch-100-Foot/dp/B0000DGARO (http://www.amazon.com/Cobra-Products-61000-4-Inch-100-Foot/dp/B0000DGARO)
(http://ecx.images-amazon.com/images/I/41G1tcUMjgL._SL500_AA300_.jpg)