Have 220V/30A, need 50A

[Speed_Dreamin']

Hello -
I need to run a device requiring 220V/50A service. House has 100A to the main panel. Circuit to the garage off the main panel is 220V/50A. Garage has 4 circuits on a sub-panel:

220V/30A (not currently used)
110V/20A (outlets)
110V/15A (lights)
110V/15A (door opener)

What are my options here?

 

[mrb]

what is this device requiring a 240v Supply?

 

[vhol5]

x2 on the device.
Intermittent or continuous?

 

[theoldwizard1]

The point the others are getting at, if your new device does not draw 220V/50A continuously, and you are not using any other devices on the #2 (20A) circuit, you would be safe to replace the breaker on circuit #1 (30A) with a 50A breaker.

Of course all of the wiring AFTER that new breaker needs to be upgraded !

 

[mrb]

I would also not do this if your panels are fpe or zinsco. The heating and cooling from the intermittent load is going to cause problems.

 

[Speed_Dreamin']

The point the others are getting at, if your new device does not draw 220V/50A continuously, and you are not using any other devices on the #2 (20A) circuit, you would be safe to replace the breaker on circuit #1 (30A) with a 50A breaker.

Of course all of the wiring AFTER that new breaker needs to be upgraded !

The device is an above ground spa (outside the garage). I have read that the heaters can be set for continuous or intermittent.

The 120V/20A circuit in the garage is for the outlets, so I do run devices off of this circuit (typical garage stuff -- air compressor, light duty power tools, drop lights, etc.)

BTW, I will likely have an electrician perform the work, and make sure all is correct and safe, just trying to understand what my options are.

 

[mrb]

spa isnt a continuous load, but you need to do a load calc to see if you are overloading the subpanel (which my gut instinct says you are). If it was for example a welder receptacle I would say go ahead and install it. But not in this case.