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Can I change where power enters a branch circuit?

4K views 15 replies 7 participants last post by  220/221 
#1 ·
Hi folks,

Been lurking for a few weeks, while I read all the old subpanel threads and several books on the 2005 NEC code. (My city still uses 2005.) I haven't seen an answer to my question below, which is really a more general question about electricity.

My garage currently has one circuit which feeds about a dozen lights and receptacles. I plan to install a subpanel and eventually split the lights and receptacles into several circuits as I create a workshop. The garage is attached but connected via a breezway and a good 40-50 feet from the main panel.

One of the receptacles is right next to where I plan to install the subpanel. Once I get the subpanel installed, can I simply run a wire from the subpanel to the receptacle to bring power to the entire circuit? Three notes:
1) Of course, the current circuit to the garage will be disconnected! I need to disconnect it before I install the subpanel to make room in the main box.
2) The receptacle is wired as "end of run" -- the circuit splits several times, and this is the end of a branch.
3) Most importantly -- there are currently NO GFCIs on the circuit.

I can't think of a reason why this wouldn't work, but I'm no electrician. I'm doing this to reestablish power for the garage door openers, lights, etc., until I can get around to splitting up the current circuit and adding GFCIs.

(In the interest of keeping this post short, I left out a lot of details about my project. I'll be happy to provide more information if needed!)

Thanks,
R.S.T.
 
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#2 ·
Sure, as long as you don't wind up feeding the circuit from both ends. Add the GFCI like you said. You can probably just replace the new first outlet with a GFCI and be done with it. Use the LOAD side for the rest of the circuit.

Some trivia, in the UK for a while they did feed circuits at both ends and then let the wires use more amps than otherwise (saved copper). The obvious problem of the circuit still seeming to work even if one side of the loop was broken eventually lead to that being phased out.
 
#4 ·
Thanks! The previous owner mucked up the wiring in my garage pretty badly, I don't want to give the inspector anything else to criticize. (Hopefully he won't look around too much.:whistling2:)

Yes, I do plan to fix the wiring, I want to get the subpanel in first.

RST
 
#5 ·
OK - Another Question

I'd like to hijack my own thread now to avoid starting a new one (assuming people are still reading this one?).

So I look at my panel tonight, and I can't figure out how to get the subpanel cable (6-6-6-6) into it. The main panel (technically a subpanel) is over a slab and in an addition, so nearly every circuit runs out through the top of the panel. At the top there are 2 knockouts remaining, both the small size (3/4"?), and they're not near each other. I'll free up two more once the subpanel is up and running, but the open spaces will not be adjacent either. The panel is mounted between two studs in a non-load-bearing wall. The wall is finished on both sides with wood paneling.

I guess my options are
1) move various wires around until I can consolidate some 3/4" holes near each other, then drill a larger hole? I'd probably have to rewire 2 or 3 breakers. Plus, the new hole might be too big depending on where the knockouts are. (e.g., it looks like Mickey Mouse)
2) drill through one of the studs and use a side knockout. Probably have to remove part of the paneling to do this, and space is tight because the panel is in my small laundry room between the washer, dryer, and some cabinets.
3) split the incoming wire into two parts BEFORE it enters the panel. Send in the two hots on the left where the breaker is, send in the neutral and ground on the right where the neutral and ground busses are. Two 6-gauge wires should be able to fit through a 3/4" knockout, I guess? (But I'm pretty sure this would not be allowed by code).
4) look into connecting the subpanel to my outdoor main breaker panel? I'd have to come down from the soffit. Maybe have to run the wire in conduit, I'm not familiar with wiring outside.
5) something else?

Option 2 is the one I'm leaning toward, I suspect options 1 and 3 are not allowed, and 4 is too intimidating for my current skill level.

Thanks again!
R.S.T.
 
#6 ·
Pictures!

1. You must enter the panel in one hole

2. You 6/4 cable is pretty burly. Trying to stuff it into a small old panel wil be a chore.

3. Take some pictures.


Is your existing sub fed with 4 wires?

It's generally a better choice to come from the main service panel.
 
#7 ·
I'll get some pictures tonight. The existing subpanel is fed with 4 wires, it's a new Square-D (not the homeline, the other one) so it seems roomy enough, just not at the top. There are neutral bars on both sides, the ground bar is on the far right but I can just run the wire around the bottom. Plus, the electrician who wired it did a good job (at least to my untrained eye) of organizing the wires.

The new subpanel for the garage is smallish (it's the old main panel from when the house has 100A service), but this will be the first cable in there, and I only plan to put in a few circuits.

Maybe I should consider an aluminum wire? More to follow...
 
#8 ·
Aluminum wire is evil...and bigger.

Get a good pic of the top of the panel.

You can get a 6/3wg NM cable thru a 3/4" hole........but it's tight.

You would need to forgo the connector and use a plastic insulating bushing in it's place. Of course this is against code and I would certainly never do it :whistling2: even though, once installed, it aint going anywhere.
 
#9 ·
I have used a 3/4" knockout for 6/3 SOOW cable for some heavy extension cords. I also plan to use 3/4" knockout when I go to wire the 6/4 aluminum to my garage subpanel at some point. 1/2" knockouts would certaintly be too small, but 3/4" should be ok for one 6/4 cable; check the package rating on the 3/4" NM connectors....
 
#10 ·
Thanks guys, here are some pictures. Top half of the panel, bottom half of the panel, closeup of top, closeup of left.

The subpanel breaker is going to replace breakers #5-#7, which currently power a well in the garage. The wire for the well enters the panel to the left of where the range wires enter. Also, I did not notice those two knockouts immediately above it (toward the front of the panel) or realize how much space was there. Perhaps I can take a hole-saw and enlarge one of them, or enlarge the one that will be left open when I remove the wire, or stuff the wire in with an insulator as 220/221 suggested (especially since I don't need to worry about an inspector now)? Otherwise, I think the wire will have to enter from the left somewhere.

Also, it looks like there might be a larger unused knockout between where the main wires and the range wires enter. Would that be large enough?

The other circuit that will be removed enters on the right-top somewhere, but as you can see there's no space there at all.

RST
 

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#12 ·
Also, it looks like there might be a larger unused knockout between where the main wires and the range wires enter. Would that be large enough?
That looks like a 1/2-3/4 concentric KO. A 1/2 KO will actually be a 7/8 hole, a 3/4 KO will actually be a 1-1/8 hole.

If the range cable is in a 3/4 KO, feed it through a different 3/4 KO (the unused one you spotted), take out the next ring in the KO the range cable is currently in, and get a regular clamp. Plastic clamps suck.

That shelf bracket may be in the working space. But that's the least of the clearance problem if the panel is over a washer or dryer or sink.

well in the garage
What's the story with that?
 
#11 ·
You can get 6/3 nm into a 3/4 ko with a plastic clamp.
The problem I know about is haveing to run the aire from the house, into a breezeway and then the garage.
Would the breezeway be considered outside, thus not allowing the nm to run throught it?
 
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