What is the maximum amount a utility bill could increase by hooking?
If you are drawing the full 30A at 120V,that would be 3.6 kW. If used 24x7 for a month, that would be 3.6 x 24 x 30 = 2592 kWh. At 5.5 cents per kWh that would be $142.56 per month added to the power bill. A couple of comments: In reality, the maximum should be 20% less than that. A high power circuit shouldn't be designed to draw full circuit load indefinitely. It should be limited to 80% of the circuit rating (24A in this case). If the circuit is following that rule, the maximum cost would be $114.05. 5.5 cents per kWh is cheap power. You should feel lucky.