DMX uses the EIA-485 standard for data transmission. EIA-485 is inherently resistant to induced noise and very tolerant of poor conditions.
However, it is a
really bad idea (TM) to mix data and
power, so much of a bad idea that the electrical code forbids it except in very controlled circumstances. There is a significant risk of electrocution and/or fire. In short, DON'T DO THIS!
@sk8rsdad, P.
Eng.