Sub panel to sub panel OR Service panel to sub panel

[Hamberg]

Best practice suggestions...

Adding a small electric heater to the garage and a circuit for general lighting and hand tool battery charging. Heater's spec is 7500W @ 240v (manufacture has max breaker size as 45A) and I can't imagine I'd need any more than a 20A circuit for everything else (probably 15A).

Current configuration is a 200A service panel and a 100A sub panel right next to it, both are filled and I there is 1 tandem breaker in the sub.

Question(s):

• think I need an 8ga run out to the garage for the heater. Assuming I add a sub panel out there (rather than a home run to the heater), is the 8ga enough for both the heater and a 15/20A circuit?
• best practice to run the new sub to the service panel (200A) or the existing sub panel (100A)?

Either way I will need to "reorganize" my current configuration. If I go sub panel to sub panel I could "get away" with 2 more tandem breakers. If I feed the new sub panel from the service panel I'm not sure I'll have enough wire to move circuits over to the sub panel.

Some future proofing to consider also; wife would like to get a pool, which means service to the pump/heater and some sort of cabana (or storage) which would need a sub panel too - complete opposite direction of garage.

 

[afjes_2016]

Is the garage attached to the house? If not attached about how far of a run from the house to the garage.

I would tap off from the main to run a sub panel in the garage if it were me. Actually either would technically be accepted as long as the present sub panel could handle the draw.

Although you have a 200amp service panel we don't know what else is electric. If you plan on putting in a pool with pump and especially heater have you done a load calculation to see if your present setup can handle all of that? You may want to try and do one (there are ones on the net) and see if your system can handle all of that load. I know you did not specifically ask this question but it is good for you to know anyway.

Is the garage detached? If so are there any other circuits running to it presently? You can only have one circuit to a detached garage. Approx how far of a run from the main panel to the garage? Is it over 100 feet? Also, this line must be a 4 conductor line, two hots, neutral and a ground.

 

[Hamberg]

Sorry, should have specified; garage is a 2-car ATTACHED. 65' to main service panel. We do have, and all of the appliances, are natural gas. There are 2 HVAC units using 240v for the condensers, 2 zones of heated floors using 240v (same circuit) and wall oven (240v) but short of those its all general lighting (95% is LED) and non-gas appliances (refrigerators, dishwasher, computers, TV's)