Tapped 2nd panel permissible

[quincyg]

I am working on a 3 unit building with 3 meters. 100A disconnect at meter for main house, 60A disc at meter for Laundry, 70A disc for unit B.
I'm sorting out circuits and loads for the building and discovered that there is a 3 wire tap before the main house 100A panel that feeds the main lugs for Unit A. The 100A wire is an old 2/3 NM(not B) which carries on past the tap near the meter to the main house panel. That other leg of the tap continues to unit A panel lugs. This wire is smaller, but I haven't sized it yet. It's either 3/3 NM or 4/3 NM. All panels are 125A rated panels.

1)I would like to bring this situation up to current code and best practices. My understanding is that having two panels controlled by a single overcurrent protection is not allowed. Not sure of code.
2)2/3 NM is rated at 60 degrees = 95A. 100 ft run. Not sure is 85% rule applies here and don't want to argue it. So this wire is undersized for 100A.
3)The 2/3 NM in photo appears to show signs of overheating in this photo. I can't tell if that is a manufacturing difference where the strands are visible through sheathing or if the wire is stressed. I also see some drip on the bottom of wire, which could be sheathing melt or gel from the tap. The wires have the same look where they land at the panel lugs 100ft away. Anyone seen wires with this look due to overheating?

I likely will want to run a new 100A home run from disconnect to house panel and a new 60A run to unit A. There's currently just a laundry panel on unit A meter that I would feed from the main house 100A panel.

Yes, Load calcs are being done!
Thanks for any advice.

 

[quincyg]

Found this from a mike holt post:
"Outside Feeder Tap of Unlimited Length Rule [240.21(B)(5)
Outside feeder tap conductors can be of unlimited length without overcurrent protection at the point they receive their supply, but they must be installed in accordance with the following requirements: Figure 3
(1) The tap conductors shall be suitably protected from physical damage.
(2) The tap conductors shall terminate at a single circuit breaker or a single set of fuses that limit the load to the ampacity of the conductors. This single overcurrent device shall be permitted to supply any number of additional overcurrent devices on its load side.
(3) The overcurrent device for the tap conductors is an integral part of a disconnecting means or shall be located immediately adjacent thereto.
(4) The disconnect is located at a readily accessible location either outside the building or structure, or nearest the point of entry of the service conductors."

So it looks like the tap is ok in principal, but the smaller gauge wire will have to land on a main breaker with appropriate rating. I believe that the main breaker can serve as the main disconnect for the panel in accordance with 225.31

 

[Fred B]

You list your occupation as a General Contractor. Best advise is to seek out an electrician locally to assist in making this compliant. Too many variables that can't be seen from your pictures and your narrative; and others things that you may not be aware of as an issue to give yes/no advice to via a forum such as this.

 

[quincyg]

Thanks for advice, and yes an electrician will be doing the work. I really do appreciate ensuring trade pros do specialty work.

As a general contractor it's my job to understand as much as possible what the situation entails and what the best remedy might be. I haven't worked with the couple of electricians who are available. They are veteran electricians, but a veteran electrician did this install in the 90s and I'm finding all kinds violations. Maybe some weren't violations in the 90s, but there are definitely some bad slim unganged 12/3 breakers and lack of ground screws, etc.
When the electrician shows up on Thursday to give his opinion I want to be informed and also have already made things accessible and traced things to be able to give him the big picture.
If he tells me things are fine as is, then I know to call the other electrician. My job is literally to understand generally what your trade is doing and maybe ask you to do something differently than you normally would. Usually this means more expensively and that also should be discussed up front. I usually require, steel boxes, manual twists under wire nuts, pigtails, no backstabbing, no 14/2, no shared neutrals, oversized equipment and enclosure, EMT or rigid instead of sched 40, no notching and butchering of framing, etc. It's a lot of headache.

Doing the same process with a flat roof. I literally hand the roofers manufacturer details for the system being installed. This is never the way flat roof are installed here. I have never seen best practices and best quality products used. Usually it's lower end product lines and minimal layers and non recommended assemblies and flashing details. An I doing the roof myself? No way if touch a flat roof. Do I do my research? Of course.
the bid for extra plies with more expensive product line and specific details will cost more and I'll have to be around to make sure the do the work to the shed upon specs.

I think my initial questions were pretty clear and general and hopefully will get some input from some others who expertise can help in with assessing the solution.
Mainly tying to figure out if that tap is a bad idea and whether those wires visually look overheated.

Sorry for the long winded answer, just trying to give a better picture of the story.

Thanks!

 

[jaggedben]

2/3 NM is fine to be protected by a 100A breaker under 240.4(B).

The different insulation texture looks like a manufacturing difference and not heat damage to me. (Extremely unlikely that you've got heat damage from undersize wires; somewhat more possible that it could be from a poor job on those splices. But again I don't see it clearly in the photos.)

It's fine to have multiple panels from one feeder if they have individual main breakers to turn them off. Whether you have a compliant tap if one is fed with smaller wire is hard to tell from the info given. See 240.21(B).

 

[quincyg]

Thanks for the input. My reading of that section is that you can tap a smaller wire as long as it's protected on an appropriate main breaker.

"(2) The tap conductors shall terminate at a single circuit breaker or a single set of fuses that limit the load to the ampacity of the conductors"

In terms of the stranding on those wires. It's actually the main 2/3 that looks questionable. Will be great to hear from any other folks of they have seen this before. I have some old nm wire laying around. I'm going to look at the sheathing on those more closely.

 

[jap]

Those look like Hot Taps.

I'm curious why they used that type of connection for this type of splice.?

Oh well.

JAP>

 

[quincyg]

I don't believe they are hot taps. The line side is the white NM is entering on the right of jbox. It doesn't carry through past the tap. That black nm 100a wire exits from the top of jbox.

I think the install is from 1991 or 92 according to permits. Maybe some old tap style.

 

[jap]

I don't believe they are hot taps. The line side is the white NM is entering on the right of jbox. It doesn't carry through past the tap. That black nm 100a wire exits from the top of jbox.

I think the install is from 1991 or 92 according to permits. Maybe some old tap style.

They are the compression pierce type connectors, or, what we call "Hot Taps".


JAP>

 

[quincyg]

Ahhh.
I wonder why they would use those on cut wires. An inferior conducting surface.

 

[jap]

Ahhh.
I wonder why they would use those on cut wires. An inferior conducting surface.

That was my question,,,,,

JAP>

 

[quincyg]

True! . Well I guess the bare minimum for the electrician will be to redo that tap and land it on a larger locking main breaker sub panel... Appropriately sized for that conductor.

 

[jap]

True! . Well I guess the bare minimum for the electrician will be to redo that tap and land it on a larger locking main breaker sub panel... Appropriately sized for that conductor.

No need to redo the tap.

I'm sure it works just as well as a hot tap.

Just seems odd using a hot tap when splicing 3 individual conductors.

JAP>

 

[quincyg]

I'm just wondering if that tap is not robust enough on that striated wire that looks questionable to me. Although I don't have an explanation as to why all three wires in that cable look like that and on both ends of the run.

 

[jap]

It's just different insulation types and a little sheetrock dust.

I'm sure it's just fine.

JAP>

 

[quincyg]

I met with the electrician today and we agreed to remove that tap and do a new homerun from the meter to the panel for that unit.

 

[jap]

I met with the electrician today and we agreed to remove that tap and do a new homerun from the meter to the panel for that unit.

How you going to do that and keep it on the same meter?

JAP>

 

[quincyg]

After a lot of circuit tracking we figured out that part of the main house was on the other meter instead of the unit. At some point that tap was done. No idea why they would have done that, but trying to rectify it now.

 

[jap]

After a lot of circuit tracking we figured out that part of the main house was on the other meter instead of the unit. At some point that tap was done. No idea why they would have done that, but trying to rectify it now.

Maybe the electrician that did the work at the time was the one living in the unit.

He probably had the AC turned down to 66d in the summertime and was baking all his favorite dishes in the winter.

JAP>