[Amps] What to do about 'Neutral' in HB amp?

[Roger Parsons]

Afraid this is an additional question rather than an answer...

This thread has induced me to do what I have been meaning to do for ages. I have an old PT3000 (yes, that is the correct number) amp which has ground and neutral tied together internally as well as a few 120V components. So a four wire connection seems to be the safest solution. 

Plug and receptacle easy - 20A twistlock. (Don't think 15A is available.)

Cable not so easy. All I can easily get here is SOOW which in 12/4 is about the thickness of an elephant's trunk. I can order SJOOW which is better but still pretty thick. Both those cables are intended for industrial use. I can't find any consumer type indoor cable. Does such an animal exist?

73 Roger
VE3ZI