Connecting 4g wire to 12g wire

[Paulski]

I am trying to figure out how to connect 4g wire to 12g wire in house wiring

Situation:

Looks like someone was planning to install a sub panel in the garage, but never finished-
-The sub panel is in the garage wired with both hots to the breaker legs, and has a neutral and ground to there own bus bars. A 20 amp breaker in the sub panel feeds 12/2 romex to power the garage. There are no grounding rods wired to the sub panel
-The 4 4g wires go in to a 1 1/2" PVC conduit that goes to under the house where the wires exit out the end of the conduit and are lying on the ground connected to 12/2 romex with wire kearneys
-The 12g romex goes up the wall and ends at the breaker panel to a 20amp breaker

I do not need a sub panel or 240v in this garage and want to make it safe/to code. I do not think I can pull new wire though the conduit, it has to many bends buried in pretty new concrete down the driveway. I'm guessing 5 90* bends

Plan:
-Gut the internals of the sub panel and just use it as a J box
-Connect a J box to the conduit under the house and connect the 4g wire to the 12g wire in the box
-Leave the 2nd hot wire disconnected in both boxes in case its needed later

How do I connect the 4g wire to the 12g wire correctly?
I was thinking of screwing a 3 wire terminal block into the J box under the house and one in the gutted sub panel box. Do they make terminal blocks that will take 4g wire on one side and 12g wire on the other side? Also, do they make some sort of plastic cover that can be screwed over the terminal block - I was think for extra safety if someone was to open the door to the gutted sub panel and stick there hand in with a live circuit. Or I could put in the breaker cover plate as an extra guard too

Or is a kearney wrapped in electrical tape acceptable in a J box for the hot, neutral and ground wire?

Edit - So I found this to use as a terminal block

McMaster-Carr

McMaster-Carr is the complete source for your plant with over 595,000 products. 98% of products ordered ship from stock and deliver same or next day.

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But is it ok to install in a J Box?

 

[Rinspeed]

Junction box and Wego/terminal blocks is the way I would do it.

 

[Paulski]

Junction box and Wego/terminal blocks is the way I would do it.

Thanks Rinspeed,
I can find wegos for 4g wire so I will get the terminal blocks

 

[wyliesdiesels]

NM-b (Romex is a brand of southwire) is not permitted for use outdoors... replace the NM-b

 

[Terry D]

Pictures?

 

[mike93lx]

NM-b (Romex is a brand of southwire) is not permitted for use outdoors... replace the NM-b

Where is there nm outdoors?

He said the conduit goes under the house and then the wires connect to nm. To me, that read as basement or crawl space.

 

[acer66]

Do you have to gut the garage panel?
Might be better to have a breaker in there so you do not have to go to the main panel when the breaker flips.

 

[Paulski]

Where is there nm outdoors?

The NM is in the crawl space

Do you have to gut the garage panel?

The panel isn't permitted and is missing the 2 grounding rods. The garage is also dry walled - I'm figuring its cheaper/easier to gut it and add the terminal blocks than to run ground cable through the walls and add grounding rods.

 

[mike93lx]

Is the panel on an outside wall? You could go down inside the wall and then out with an LB for your ground wire.

Even if you don't need the service now, you are so close to having a good setup. Seems odd to throw it away for a single 20a circuit

 

[alfredeneuman]

The panel isn't permitted

Are you planning on getting a permit for your modifications?

 

[Rinspeed]

Thanks Rinspeed,
I can find wegos for 4g wire so I will get the terminal blocks

I didn't check the exact specs on wire size but one of these would even be cleaner than the Wego blocks. Most of the Wego I've used are Din rail mount.




https://www.zoro.com/bussmann-min-p...MIzsP8o_eu9QIVG_LjBx2O9wdnEAYYASABEgJ9vPD_BwE

 

[wyliesdiesels]

Where is there nm outdoors?

He said the conduit goes under the house and then the wires connect to nm. To me, that read as basement or crawl space.

He said the NM-b is on the ground so i took that to mean its outdoors

 

[Fasthotrod]

I do not think I can pull new wire though the conduit, it has to many bends buried in pretty new concrete down the driveway. I'm guessing 5 90* bends

Just wanted to mention that if it indeed has five, 90 degree bends, it's not to Code.

Per the NEC:

“There shall not be more than the equivalent of four quarter bends (360 degrees total) between pull points, for example, conduit bodies and boxes.”

 

[mike93lx]

Getting it permitted with the conduit inaccessible may be difficult as they can't verify depth

 

[alfredeneuman]

Getting it permitted with the conduit inaccessible may be difficult as they can't verify depth

I just find it "curious" that the first thing mentioned wrong was the panel didn't have a permit.
The easiest way to splice the wires together would with insulated taps (like NSI's Polaris)

 

[Bert_]

Getting it permitted with the conduit inaccessible may be difficult as they can't verify depth

Is that even a thing? I've hardly ever left a trench open for inspection. I wouldn't want to leave my equipment sitting on a job for a couple days just waiting, need to be moving on to the next one.

 

[ycgoat]

I am lazy and did not read the entire post but the easy old school method of connecting #12 to #4 is a split bolt then if its current carying taped with 3 layers of rubber and 3 layers of vinyl

 

[acer66]

Is that even a thing? I've hardly ever left a trench open for inspection. I wouldn't want to leave my equipment sitting on a job for a couple days just waiting, need to be moving on to the next one.

Yup, I was not allowed to close the trench when I ran power to the garage until the inspector verified the depth.
Maybe it was because it went under two driveways and minimum depth changes with the type of surface of the driveway.

 

[mike93lx]

Is that even a thing? I've hardly ever left a trench open for inspection. I wouldn't want to leave my equipment sitting on a job for a couple days just waiting, need to be moving on to the next one.

Definitely. But you should be able to get a trench inspection pretty quickly. I have also heard of people leaving a scrap piece of conduit vertically in the trench so an inspector can run a tape measure down to the pipe

 

[PoorUB]

I am still trying to wrap my head around the concept that you have a sub panel, in the garage, wired in 4 ga, and you want to get rid of it? If I understand the house end is wired to 12 ga?

Why not just finish up the panel and get it wired in properly? Or am I missing something? In five years you might want to charge your EV, then you will be buying a panel and ripping out the mess you make now.

 

[Terry D]

Is that even a thing? I've hardly ever left a trench open for inspection. I wouldn't want to leave my equipment sitting on a job for a couple days just waiting, need to be moving on to the next one.

We are required to get a ground cover inspection