[howardandhenry]

Hello.
Info: Im in New York state. Main panel is 100 amps with no 240 circuits currently. Circuit panel is in the front of the house. Everything I would like to hook up is 240 volts and in the back of the house.

Need to hook up
Hot water tank – 20 amps
Electric cook top - 30 amps
Electric oven – 15 amps

My question is
Should we
A)Run wiring to a 70 amp Subpanel in the back of house with (3) 240 circuits and hook everything to that?
Or
B) Run 3 separate lines off the main panel to the appliances?
C) Or something else entirely?
Any guidance, suggestions and help is much appreciated. Thanks.

 

[howardandhenry]

First, thanks for your response. To answer your questions, yes there is room in the main panel. The runs would be approximately 75 ft each from front to back of house. Difficulty would be quite easy I'd assume. Just a straight shot through the attic and down to each appliance.

 

[howardandhenry]

I really appreciate the extensive input guys!!! So I will try to respond to everyone. But before I do I see the answers are split down the middle which leads me to another question. Now that I know these two options are both acceptable, what are the pros/cons for these two options? What would make you choose one over the other?

seharper
haaa yes I like to cut costs when possible but I just assumed 70 amps was good according to the math I did. After reading your response I now realize, especially with the tire analogy, that I should go higher amps. So you're saying I should run 100 amp subpanel from a 100 amp main panel correct?

rjniles
I am told this but my model says 18.75 so I just rounded up to 20. Should I still do 30amps? The model is @ this link if you're interested. https://www.homedepot.com/p/Rheem-P...ric-Tank-Water-Heater-XE40M06ST45U1/205810725

Jim Port
Yes I've done a load calculation and it seems doable.

 

[howardandhenry]

Thanks everyone! 30 amp for the water tank it is! So, for all electrical devices, as a general rule you should increase to 125% normal amps as rjniles suggested for the water tank? I will have to do some recalculations for these appliances if so. So far I am leaning towards running straight from the main panel but would like a couple more opinions before that decision is made. Thanks everyone for your time.

 

[howardandhenry]

Headed to the hardware store now to pick up the 10/3. Thanks!

Not all appliances are a continuous load. In residential the WH is about the only one; electric cook top and oven are not.

I would not install a sub unless you are short on breaker spaces. Run 10/2 for the WH, run 10/3 for the cook top, Run 10/3 for the oven. You could use 12/3 for the oven but 10/3 will future proof the install.