Difficult panel replacement

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Coppersmith

Coppersmith

Senior Member
Location
Tampa, FL, USA
Occupation
Electrical Contractor
Anybody got a good solution for replacing this panel? I can't come up with anything easy.

Conditions:
* All the branch wiring is coming through one 2" PVC chase pipe so I expect the inspector to say they need to be separated for conduit fill and derating reasons. I'm guessing that all the branch wiring is coming down from the attic inside the block core but it could be between the block face and the drywall.
* The cables are NM so not allowed in outdoor conduit.
* There is just 19" between the wall where the pipe emerges and the meter can.
* The walls are block and the other side of the pipe wall is a bedroom.
* The panel is mounted on a wing wall. The other side is a separate residence. This is a duplex.
* There are eleven 20 amp 120v, three 30 amp 240v, and two 50 amp 240v circuits.

The best solution I can think of is to:
* Remove the pipe.
* Cut a vertical channel about 2" wide and 16" tall in the block outside with the pipe hole at the bottom.
* Mount a 4x18 NEMA 3R trough over the channel (against the wall) with the NM cables in individual NM connectors. (The connectors will not be accessible after install. Is this a problem?)
* Connect the new panel to the trough via a sufficient number of pipes to meet derating and fill requirements (probably 3).
* Run THHN from trough to panel making joints in trough.
* The new panel will have to be mounted below the meter can.
* Correct me if I'm wrong. I think no AFCI's will be required since the extensions to the wires will be less than six feet.

20200526_131754a.jpg

20200526_132419a.jpg
 
Last edited:
LarryFine

LarryFine

Master Electrician Electric Contractor Richmond VA
Location
Henrico County, VA
Occupation
Electrical Contractor
You may have room for a vertical surface-mounted 4x4 trough where the PVC is now; shorten the projecting PVC flush with the wall, cut a groove around the PVC, put on a new MA, add a vertical surface-mounted trough between the house and the panel, and nipple into the new panel. A short nipple will not require conductor derating, so a single one will suffice.

However, I would start by asking the inspector to look at the existing installation, and ask what may and may not remain. He may say grandfathering will allow the PVC to remain.
 
mikeames

mikeames

Senior Member
Location
Germantown MD
Occupation
Teacher - Master Electrician - 2017 NEC
Not sure what the best way is, but the idea of a trough sounds reasonable. If you nipple to trough to the panel you don't need to adjust ampacity less than 24". The NM in the conduit is different. There was just a discussion on this. Different but similar. https://xenforo.mikeholt.com/thread...branch-circuit-entering-through-1-ma.2553855/ I wonder how your inspector would view the conduit?


EDIT --- JUST as I was about to post Larry beat me.
 
Coppersmith

Coppersmith

Senior Member
Location
Tampa, FL, USA
Occupation
Electrical Contractor
LarryFine said:
However, I would start by asking the inspector to look at the existing installation, and ask what may and may not remain. He may say grandfathering will allow the PVC to remain.
Click to expand...

I would prefer to use the existing panel as a j-box and place a new panel below it. That would require the inspector to allow the PVC chase to remain. Before I discuss that possibility with the inspector I wanted to hear all the suggestions. I haven't had any luck getting inspectors to allow this situation the last couple of times I tried.
 
Coppersmith

Coppersmith

Senior Member
Location
Tampa, FL, USA
Occupation
Electrical Contractor
LarryFine said:
You may have room for a vertical surface-mounted 4x4 trough where the PVC is now; shorten the projecting PVC flush with the wall, cut a groove around the PVC, put on a new MA, add a vertical surface-mounted trough between the house and the panel, and nipple into the new panel. A short nipple will not require conductor derating, so a single one will suffice.
Click to expand...

Sounds like you are suggesting having all the cables come through one pipe into the trough. I don't think that is compliant since the cables are required to be fastened with connectors to the trough unless the pipe is part of a complete raceway system which it is not AFAIK.
 
W

wwhitney

Senior Member
Location
Berkeley, CA
Occupation
Retired
If you want to properly attach each cable to an enclosure, then you are going to need to open up the wall and separate the cables.

Are there ~15" wide panels that can have a 4" wide auxilliary gutter attached to the side? That would fit in your 19" wide space and you could install them tight to the insider corner of the wall. Then you can individually secure the cables along the right side of the gutter, and the cables aren't ever in a wet location. Plus they may reach to the breakers without extension.

Cheers, Wayne
 
Coppersmith

Coppersmith

Senior Member
Location
Tampa, FL, USA
Occupation
Electrical Contractor
wwhitney said:
Are there ~15" wide panels that can have a 4" wide auxilliary gutter attached to the side? That would fit in your 19" wide space and you could install them tight to the insider corner of the wall. Then you can individually secure the cables along the right side of the gutter, and the cables aren't ever in a wet location. Plus they may reach to the breakers without extension.
Click to expand...

That sounds very interesting. I'll try and find those to evaluate.
 
W

wwhitney

Senior Member
Location
Berkeley, CA
Occupation
Retired
To be clear, I don't know if they are commercially available, it's just a product I would hope would exist.

Both Article 366 Auxilliary Gutters and Article 376 Metal Wireways require derating when exceeding 30 CCCs in a cross section. You have 32 CCCs, so you'll want to ensure that the topmost cable and the bottommost cable never cross each other. [That way no cross section has both cables, so each cross section has at most 30 CCCs.]

I guess if you can find, say, a 4" x 4" x 24" metal wireway that is listed 3R in the vertical orientation, that would work. You'd have enough height to separately secure the cables to the right side of the gutter, and then you could connect the gutter to the new panel with 1 or 2 chase nipples below the level of live parts in the panel.

Cheers, Wayne
 
McLintock

McLintock

Senior Member
Location
USA
Occupation
Electrician
Coppersmith said:
Anybody got a good solution for replacing this panel? I can't come up with anything easy.

Conditions:
* All the branch wiring is coming through one 2" PVC chase pipe so I expect the inspector to say they need to be separated for conduit fill and derating reasons. I'm guessing that all the branch wiring is coming down from the attic inside the block core but it could be between the block face and the drywall.
* The cables are NM so not allowed in outdoor conduit.
* There is just 19" between the wall where the pipe emerges and the meter can.
* The walls are block and the other side of the pipe wall is a bedroom.
* The panel is mounted on a wing wall. The other side is a separate residence. This is a duplex.
* There are eleven 20 amp 120v, three 30 amp 240v, and two 50 amp 240v circuits.

The best solution I can think of is to:
* Remove the pipe.
* Cut a vertical channel about 2" wide and 16" tall in the block outside with the pipe hole at the bottom.
* Mount a 4x18 NEMA 3R trough over the channel (against the wall) with the NM cables in individual NM connectors. (The connectors will not be accessible after install. Is this a problem?)
* Connect the new panel to the trough via a sufficient number of pipes to meet derating and fill requirements (probably 3).
* Run THHN from trough to panel making joints in trough.
* The new panel will have to be mounted below the meter can.
* Correct me if I'm wrong. I think no AFCI's will be required since the extensions to the wires will be less than six feet.

View attachment 2552518

View attachment 2552519
Click to expand...

I stick of dynamite will work wonders too!


“ shoot low boys their riding shetland ponies”
 
E

Edval69

Member
Location
New Haven Ct
Occupation
Electrician
Great details. my opinion is the 2inch conduit is a less than 2foot sleeve for protection of the nm cables. The cables are probably installed in the inside wall to a location. Is this a damp location idk. J- box on opposite wall with thhn and a new panel
 
Coppersmith

Coppersmith

Senior Member
Location
Tampa, FL, USA
Occupation
Electrical Contractor
Cow said:
I would try and fit one of these in there and just take that existing 2" with all the cables right into the side of it:
Click to expand...

It wouldn't be code compliant. The pipe is just a sleeve probably 9" long. The cables are required to attached to the panel with connectors.
 
C

Cow

Senior Member
Location
Eastern Oregon
Occupation
Electrician
Coppersmith said:
It wouldn't be code compliant. The pipe is just a sleeve probably 9" long. The cables are required to attached to the panel with connectors.
Click to expand...

We run into lots of things during a typical panel change that may not be code compliant. It does not mean we have to fix every last one of them if we are only there to change a panel. Of course, if it's a true safety hazard we will address it. In this case, I'm 99% sure our inspectors over here would not make us tear up the wall to get rid of the sleeve just to bring the cables in through separate Romex connectors. The cost/benefit ratio just isn't there. I'm glad our inspectors over here exercise some common sense with remodels/retrofits.
 
LarryFine

LarryFine

Master Electrician Electric Contractor Richmond VA
Location
Henrico County, VA
Occupation
Electrical Contractor
We're generally allowed to replace like with like, sometimes without a permit, as a repair.

For example, a panel above a washer or a counter, as long as the original install passed as compliant.
 
Coppersmith

Coppersmith

Senior Member
Location
Tampa, FL, USA
Occupation
Electrical Contractor
I spoke with the inspector and he asked me to send him a written proposal. As I was drawing the proposed design I started to wonder if there is really a code violation here. The sleeve with the incoming branch wiring is estimated to be only 9" long. Is that long enough to be an overheating risk? Can someone quote me the section number of the violation here? The overheating issue was the only one he mentioned. Then there is the fact that the cable is NM in outside conduit which is a violation I believe, but again it's only about 4" exposed so is it really a violation?

Below is what I would like to do if he approves leaving the sleeve in place.
Proposed panel install.png
 
C

Cow

Senior Member
Location
Eastern Oregon
Occupation
Electrician
Nipples 24" and less don't require conductor ampacity adjustments. That should be a code the inspector should know off the top of his head.

Now that I see your drawing, I still can't help but think you and the customer would be much better served with the metermain I posted above. That would get the customer a new meterbase on top of having less clutter(two panels in addition to a meterbase on their wall). Unless they aren't allowed in your area?

Using a metermain, you would have a real chance that some of your circuits would reach breakers without needing to be spliced and extended.
 
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