How do you convert the dryer's 240V to 120V?
Likely your third problem is that you're going to be maxing out your 15A circuit too. My guess is that the next power supply you add is going to tip the load and trip your breaker.
I'm running the miners on the 50amp washer/dryer circuit. No way would I run all 6 Antminer S1's on a 15amp circuit; it would probably trip the circuit breaker or start a fire. I've read that 15amps can support 3 Antminers and 50amps support about 18. I definitely did my research beforehand.
I got ahead of myself and made a bad assumption; the socket that I am on is not 50amps, it is 15amps. I made the assumption that because it was next to the dryer socket that they were on the same circuit but that was proven wrong when I tested the circuit breakers today. I'm going to have to split up my Antminers and have them in different rooms so that I don't overload any one circuit. I would like to utilized the actual dryer socket but as of right now, I don't know how. I am much more safety conscious nowadays and am glad that I checked my circuit breakers.
either:
1) go to home depot and buy a 'whip' cord that has a plug matching your outlet and a 3-6' terminated wire lead. either wire these into a new outlet/housing or into a larger PDU capable of L6-30 or better socket. There are distribution options that can handle 50A and allow you to wire into its terminals or splice to its cable
2) go to a specialty shop such as greybar or nedco and buy a big 50A locking outlet that is designed for industrial applications and then buy a sompatible server PDU.