Add sub panel to garage from existing 240v 50A?

[amt]

I have detached garage which has no electrical panel, but has 3 lines run to it from the main house panel. There is 1 120v (20 amp I believe), 1 240v 30A, and 1 240v 50A. I am really in a need for more 120v circuits. Is it possible to use one of the 240v lines to route to a new panel in the garage, and from there, a few 120v 20A and 1 or 2 240v 30A circuits from this new panel? I would just use metal conduit for all of the new lines, and use the existing 120v only for lighting. FYI, this is all original wiring from ~1978. I am pretty sure the 204v 50A line is 2 conductor plus a ground. Could the ground be used as a neutral for a new sub panel, and then add a ground?

 

[Gary S]

Some code issues here.

My limited knowledge says that a detatched garage needs 4 wires, not 3.

I also believe that you are allowed only a single power feed to the building.

I would recommend pulling out all the existing wiring and pulling in new wire suitable for the size panel you need.

 

[Aceman]

You can only have one feed to a separate structure with very few exceptions. None of which you meet.

It IS possible to repurpose one of your existing circuits and use it for a subpanel. But you will need to abandon all the other cables coming out to your garage.

First things first though, what kind of wire is it coming out to your garage? Romex, UF cable, thhn in conduit?

 

[amt]

Here's a couple pictures I took of the box mounted on the outside of the garage. This is where all the lines route through. There is a common conduit which all of these lines run through, between the house and garage. I do not know enough to recognize the different wire types. Hopefully someone here can easily identify these. I do believe the 3 large wires are for the 240v 50A line, the red & white wires with red tape are probably the 240v 30A (20A?) line, and that leaves two more sets of white & black wires, which I am guessing is for 2 120v lines. And finally, 6 ground wires (why 6 instead of 4 or 3?).

So, maybe I do have 2 120v lines to the garage. If so, maybe I can make do with that.

However, if I were to add a panel, would I then discard everything but the 3 wires currently used for the 240v 50A plus one of the grounds?

If I were to stick with what I have, and just use the lines I have, but relocate some of the outlets, does code still force me to "start over" with a single run and a sub panel? I appreciate the help!


pictures on their way, just a sec...

 

[amt]

Here are the photos:

 

[pattenp]

Looks like you have 3 sets of ??/2 romex coming into the box being spliced together so that's why you have 6 ground ends.

Edit: All the romex that's under ground should be removed. It's not rated to be in wet areas such as in conduit under ground.

 

[amt]

So all of the grounds likely come from the romex cables? If so, then would I be better off pulling all new wires, like 3 x 6 AWG copper plus a new ground?

 

[pattenp]

I believe all the bare grounds are from the romex. What you can do depends on those 3 large wires as to what type and size wire it is. You may be able to keep those 3 and pull in a new equipment ground as you pull out the romex.

Edit: Not knowing the age of the wire and its condition you are probably better off with all new feed wire. Unless you can verify it's the right type wire and is in good condition and is large enough for what amps you need.

So all of the grounds likely come from the romex cables? If so, then would I be better off pulling all new wires, like 3 x 6 AWG copper plus a new ground?

 

[theoldwizard1]

Very strange ! Black and whites joined, some labeled red.

What are the heavy cable that come in the back and immediately make a 90° turn going down ?

 

[amt]

I do not know the exact cable type for those heavy ones. I assume they are for the 50A circuit that I have in the garage. I guess I need to find the wire type a AWG for those.

 

[pattenp]

No black and whites joined together. It's whites to whites and blacks to blacks.The wires are taped/bundled together as to the single romex cable. The whites that are labeled red are the hot leg on a 240V circuit. All the romex are single circuits passing through this box. That's how it appears to me.

Very strange ! Black and whites joined, some labeled red.

What are the heavy cable that come in the back and immediately make a 90° turn going down ?

 

[wyliesdiesels]

IMHO, it would be more work to make this code compliant vs. putting in a new feeder and subpanel with added capacity eapecially since the wire type of the larger gauge wires is unknown.

If u CAN figure out what type of wire it is AND its listed for underground use, then use it, add an EGC(ground), 2 ground rods, and abandoned ALL the other wires feeding the garage!!

Let us know if u figure out the wire type and post it here. We'll let u know if its the right type!

 

[theoldwizard1]

No black and whites joined together. It's whites to whites and blacks to blacks.The wires are taped/bundled together as to the single romex cable. The whites that are labeled red are the hot leg on a 240V circuit.

I couldn't see the second "red" wire nut !

 

[amt]

add an EGC(ground), 2 ground rods, and abandoned ALL the other wires feeding the garage!!

Does adding a ground require running a new wire from the garage to the main panel at the house? Or can I run a ground to just ground rods?

 

[Highbeam]

Back to the main for one ground ground. You will also have ground rods on another ground at the subpanel.

 

[pattenp]

The EGC is equipment ground conductor, GEC is grounding electrode conductor, Grounded conductor is the neutral. So going from there.. the EGC is needed by newer code and it runs from the main panel to the sub-panel with the supply conductors. If your 3 wire feed was installed before this change you do not have to add the EGC as long as there are no other continuous metal pathways bonded to the grounding systems in both buildings. Regardless of the EGC you need to have the Grounding Electrode System which consists of the grounding electrode conductor and the grounding electrodes (rods). If you can add the EGC then by all means do so.

 

[amt]

Thanks for the info. I will try to identify the heavy wire for the 50A circuit (actually looks like the breaker is 60A, so I am hoping it's something like 6 AWG THHN copper).

I have a slightly better understanding why there are two 120v lines to the garage. One is for some outdoor lights on the garage which are switched from the house. The other is the 120v lights and electric for the garage. I can probably do without the remote switch, so I think I can get down to one line and a new panel assuming the 3 wires are suitable and I can pull a 4th.

 

[pattenp]

You can leave the line that's a switch loop as long as the power source for the garage lights originate from the garage panel. In other words the wire for the lights is not to supply the power to the lights from the house panel.