Please assist with Sub Panel

[heitjer]

Hello,
I have a Ecoflow Delta Pro in the house and want to connect a freezer in the garage. The garage is about 50 ft disconnected from the house and I just ran a conduit with a 10/3 Romex in there with the intend to connect to the 30 amp outlet from the Delta Pro.
The cable is rated for the 30 amp but I would feel better if I had some 'sub panels' on the house and the garage side.

I was thinking about a sub panel at the house that connects to the Delta Pro on its 30 amp outlet. Then feeds into a box with a 20 amp breaker for the garage plus one 10 amp breaker for the house and a second sub panel on the garage side with two 10 amp breaker for two circuits.

Can I use these?

• Box for Garage and House
• 10 amp breaker
• 20 amp breaker

 

[x98myers7]

assuming you're in the USA, you can't use romex in conduit. big no-no. THHN/THWN wire is what you need, metal clad or uninsulated.

I think you're going about this wrong. you don't need to run a 30amp line to the garage for the freezer. IMO, you don't need a subpanel for a 120v run to the garage. just run an AC line from the main house panel to a standard 120v receptacle.

then connect the eco flow to the house main panel with a manual transfer switch. reliant controls makes ones that works great for 6 circuits. ~$330. then connect the eco flow to the "generator" input with a 30amp NEMA TT-30R receptacle.

alternatively... i think reliant also makes a "furnace" 15amp manual transfer switch for a single circuit for ~$80.

 

[heitjer]

Yes, I am in the US. Thanks for the info/warning on the conduit, I think its not Romex. I just checked Cable and it says:
"United Copper Industries (UL) 10/3 NM-B 600V E194030" Would this work?

 

[x98myers7]

unfortunately, no. NM-B is not underground rated.

 

[Tecnodave]

The rule is called “Conduit in Conduit” you cannot put any jacketed wire in a conduit or raceway, Wire heating is the reason, the outer jacket of “Romex” or other jacketed wire must not be installed in a confined space. THWN wire is needed here as it can dissipate the heat to the conduit. Becuase this will be underground it cannot be THHN as it is not rated “wet”

THHN....Thermoplastic, Hot, Hot, (90 deg C.) Not waterproof
THWN...Thermoplastic, Hot, Hot, (90 deg C.) Waterproof

 

[heitjer]

Thank you very much for your thoughtful and extensive explanation. I will make sure I get the right wire. I am glad you picked up on this.
Back to the breaker. Would you not recommend a breaker before leaving the house for the run to the garage? I understand the delta pro has its own breaker but I feel it would be better.

 

[x98myers7]

any time you want to interconnect circuits to the main panel on a home, you need a transfer switch. a transfer switch prevents you from backfeeding any amount of power to the grid if it goes down. the transfer switch basically is either "grid" or "generator". you can choose either one as the source for the circuit.

btw, the reliant controls 6 circuit transfer switch has 120v 20amp and 15amp breakers pre-installed. i wired mine up in about 4 hours. it's pretty easy and the instructions are clear.

 

[x98myers7]

THHN....Thermoplastic, Hot, Hot, (90 deg C.) Not waterproof
THWN...Thermoplastic, Hot, Wet, (90 deg C.) Waterproof

you knew that, though. W=Wet rated.

 

[heitjer]

Well, I don't want to connect circuits to the main panel. As far as I am concerned everything downstream from the Delta Pro is its own circuit just like a long extension cord. I was just concerned about the run between the house and the garage and protect that piece.

I understand the transfer switch issue but did not want to go this route as this not practical in my situation. I just wanted to ensure that the freezer is always on the Delta Pro.. So any power outage is not affecting it.

 

[x98myers7]

got it, okay.... i misinterpreted the OP then. you mentioned sending a 10amp circuit to the house.

in that case, I would suggest a standard 120v/240v 100amp panel from a big box store fed directly by a NEMA TT-30R receptacle box. plug the ecoflow into the receptacle box, which is the input to the panel. add a 30amp breaker to the line in. then, run your lines accordingly from the panel just like a standard residential install. all that unlisted Chinese crap on amazon is going to be a fire hazard. spend a few extra $ on listed UL equipment, that way if you ever sell you don't need to undo/remove a bunch of stuff.

 

[heitjer]

OK - understand, and again thanks for the help.

Delta Pro 30 amp --> NEMA TT-30R (needs male plug) --> Square D 100 amp load center (one 20 amp to garage, one 10 amp spare in house) --> run to garage (I ordered the right cable) --> Square D 30 amp load center (one 10 amp plus one 10 amp) --> freezer

 

[x98myers7]

don't forget to buy grounding bars for the panels... they usually don't come with them