I have a rig with 6 Rx 470 4GBs that use between ~62 to ~84 watts in HWMonitor depending on how much I was able to undervolt the particular GPU. My total power draw at the wall for the entire system is 760 watts mining ZEC. Hope that helps.
Damn thats really good I am using/getting around 600watts on Ethereum for 4 RX 470
When I dual mine ETH and DCR with Claymore's miner the same rig consumes ~910-~945 watts at the wall (fluctuates allot with the current miner version). ZEC is quite abit easier on the power draw, cooler and quieter too