Main or sub panel or both

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#1

Originally Posted By: rchoreyii
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I have a question. Just did a brand new house today.


The main service disconnect was on the outside of the garage wall for power. On the inside of the same wall, was what appeared to be a main panel but without a disconnect. Is this considered a sub panel? Or would it be the main with the main disconnect outside?

I have not run into this before.

Also, there were 3 hot wires on the panel inside the garage that had wire nuts on them. I can't find anything on if you can splice the hot that way inside a panel.

thanks for any help.

--
Ron Chorey
LAS CRUCES Home Inspections
rchorey@comcast.net
rchoreyii@nm.nachi.org

#2

Originally Posted By: Joey D’Adamo
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That should be okay because there is a main disconnect, regardless of the fact that it doesn’t go with the panel. That panel should be wired as a “sub” panel with a floating neutral bar.


Also, that splice should be ok as long as one of the conductors attaches to something within the panel. I think (not 100% sure) the part of the NEC which specifies panels can't be used as junction boxes only would apply if the wires entered the panel and were spliced only to themselves and left again. Can someone confirm?

#3

Originally Posted By: rchoreyii
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http://www.nachi.org/bbsystem/usrimages/m/main_disconnect.jpg ]


[ Image: http://www.nachi.org/bbsystem/usrimages/p/panel3.jpg ]

–
Ron Chorey


LAS CRUCES Home Inspections


rchorey@comcast.net


rchoreyii@nm.nachi.org

#4

Originally Posted By: rmoore
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In the first image…the service equipment panel with the service disconnect…there are three grounding conductors. I assume two of them are GECs (grounding electrode conductors) going to water piping, ground rod (etc). The third is probably the EGC (equipment grounding conductor) and connected to the grounding bar in the “main” panel (wired as a sub-panel), although I can’t actually see that connection in the 2nd photo. All good. As long as the grounding (ex-neutral) bar on the left is bonded to the panel (also can’t see that) this looks “good to go”. Wire-nutted pigtails to a breaker are allowed.


Does the sheathing used for labelling constitute excessive sheathing? ![eusa_think.gif](upload://lNFeGuTetUAtwNVgUSOuUzgrGGK.gif)

--
Richard Moore
Rest Assured Inspection Services
Seattle, WA
www.rainspect.com

#5

Originally Posted By: Greg Fretwell
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There is effectively no rule against splicing in a panelboard enclosure as long is you don’t make it too crowded. That will certainly be a judgement call even though there are some numbers to go on. The problem is it is hard to determine what the actual fill works out too.

#6

Originally Posted By: jmyers
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Greg,


Bob B and I had this discussion some time ago. From what I know, it would take an aweful lot of wire to fill one of those to the "fill rate" guide in the NEC. More than you would typically find in a panel, even with splices all over the place.

--
Joe Myers
A & N Inspections, Inc.
http://anii.biz

#7

Originally Posted By: jmyers
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I agree, nothing wrong with the splices inside the panel, assuming they are done properly.


Joey,

Not sure what you meant by using the panel as a junction box, never heard of that reference before. I know in my area, they typically use the old panel as a junction box when installing new panels.

I have never found any reference that would make it illegal according to codes, after all they were made for electrical connections. One would have to assume all the holes were plugged up and wire connectors were used.

--
Joe Myers
A & N Inspections, Inc.
http://anii.biz

#8

Originally Posted By: rmoore
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Here?s the code section.


Quote:
NEC 312.8 Enclosures for Switches or Overcurrent Devices.
Enclosures for switches or overcurrent devices shall not be used as junction boxes, auxiliary gutters, or raceways for conductors feeding through or tapping off to other switches or overcurrent devices, unless adequate space for this purpose is provided.

The conductors shall not fill the wiring space at any cross section to more than 40 percent of the cross-sectional area of the space, and the conductors, splices, and taps shall not fill the wiring space at any cross section to more than 75 percent of the cross-sectional area of that space.


This was discussed over at that ?other site? some time ago. The fill rate intrigued me so I did a little ?research? and came up with the following...

The clear side wiring space, either side in my large 200-amp Square-D appears to be about 3" x 3" or 9 square inches. Doing some math on #12 wires, at a generous 1/8" diameter including insulation, it would take about 90 #12 to have a total cross section of 1 square inch. 40% of 9 sq" is 3.6 sq". 3.6 x 90 = 324 #12 conductors! Either side!

Clearly, that is a ridiculous example, but I can't find fault with my math. Even if you substitute much bigger #4s for the #12s it still comes to over 40 #4 wires, each side (equally silly).

We?ve all seen messy wiring in panels that appear at first glance to be overfilled. That wiring, like trees, is probably 90% air (although I can hit the 10% with a golf ball 100% of the time). ![icon_sad.gif](upload://nMBtKsE7kuDHGvTX96IWpBt1rTb.gif)

--
Richard Moore
Rest Assured Inspection Services
Seattle, WA
www.rainspect.com
#9

Originally Posted By: jmyers
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RM,


The point that I was making was that you could use them once you remove the breakers, switches or fuse blocks, you do basically have a junction box. Since those components were removed, you would not be breaking the codes.

I see it all the time in retro's and I don't really see a problem with it. In the same manner, from what you are saying you would not be able to have splices in electric panels which I also don't have a problem with, assuming of course they are not crowding the panel. What is your take on that, would splices (pigtails) in the electric panel, constitute using it as a junction box? Joe T. maybe you can chime in here and give us your take.

I agree about your math and I don't see any problems with it, although I do agree the amount of wires that it would take to fill a panel is pretty ridiculous. In the end, you are allowed to put that many in there and that is what counts.

--
Joe Myers
A & N Inspections, Inc.
http://anii.biz

#10

Originally Posted By: Greg Fretwell
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Splicing a pigtail on a wire does not increase the box fill at all. Splices have a fill count of zero. The only question is about wires that simply pass through the gutter space without landing. That is still legal as long as they don’t exceed the magic numbers.

#11

Originally Posted By: jmyers
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Greg,


Like I said, it really depends on the installation. I have seen plenty of installations that I would not begin to touch, they were so crowded to begin with (typically older and smaller panels). You add a bunch of wire nuts with pigtails in there and your outta here, if you know what I mean.

While I am certain it is not illegal "per se", I don't like to see sloppy work when it is done, just makes for a dangerous installation.

Exceeding wire fill has been proven to me very difficult to achieve. Not that it could not happen, just it would take more wires than you would possibly need in the panel to begin with.

--
Joe Myers
A & N Inspections, Inc.
http://anii.biz

#12

Originally Posted By: jtedesco
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Ronald:


Let it be, leave it alone, the job was passed and inspected, save yourself grief and wasted time.

As far as the use of the cabinet as a raceway and for splicing, I too have been trying to make it clear to the new kids on the block that this rule was written only to allow feeders to be passed through a combination cabinet that also had a panelboard installed.

The 40% rule was to apply to the feeders that raced up through the floors of a multistory building.

The splicing at 75% was to permit the taps to the main lugs in the panelboard.

The example of just how many wires is allowed is accurate but is really a joke in my mind.

I am planning to send a proposal in to get this annoying issue fixed in the next code.

I am sure that the CMP 9 Chairman Bill Hogan (Former Chicago Chief Electrical Inspector) and members never anticipated this interpretation to allow the application as many think it should be.


PS: The Main comes first and the next is the subpanel.

--
Joe Tedesco, NEC Consultant

www.nachi.org/tedescobook.htm

#13

Originally Posted By: jmyers
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Joe T,


Thanks for chiming in here and setting the record straight. As always, we appreciate your good advice. ![icon_biggrin.gif](upload://iKNGSw3qcRIEmXySa8gItY6Gczg.gif)

--
Joe Myers
A & N Inspections, Inc.
http://anii.biz

#14

Originally Posted By: Greg Fretwell
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Joe T what is your proposal?

#15

Originally Posted By: jtedesco
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Greg Fretwell wrote:
Joe T what is your proposal?


I have until the beginning of November, then the proposal date ends, so I will check the old codes and preprints and suggest that the 312.8 rule be clarified.

It will be interesting, any suggestions?

Maybe others will send in a proposal too.

--
Joe Tedesco, NEC Consultant

www.nachi.org/tedescobook.htm
#16

Originally Posted By: Greg Fretwell
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One thing should be pointed out. From an engineering standpoint “messy” might actually be better than “neat”. If you look at a panel where all of the conductors are laced into nice neat bundles in the gutters you may also be looking at bundles that are cooking inside. If they run loosely down the gutter space and have no real contact with each other they will not contribute to mutual heating.


Certainly “organized” is better than a rat’s nest but I hate to see neat bundles if I am thinking about heating. Usually a crowded panel is going to be one with lots of piggyback breakers or double taps that may not really belong in that panel. I would rather see the panel upgraded to a larger <volume> one, even if it meant half of the conductors had a splice in them.


A more elegant solution is to put a gutter above/below the new panel, splice in there and bring a number of raceways into the new panel. Bear in mind that even a short (<24") nipple is still limited to 60% fill

#17

Originally Posted By: jmyers
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Greg,


While I agree with you about the bundling of wires, I disagree with the messy portion of your statement. IMO, messy is just as, if not more, dangerous than their bundled counterpart. Working on those "messy" panels gets dangerous when you think that you turned off the power to the circuit you are working on, when in fact you traced the wrong wire in that mess!

--
Joe Myers
A & N Inspections, Inc.
http://anii.biz

#18

Originally Posted By: Greg Fretwell
This post was automatically imported from our archived forum.


You are still not addressing the engineering only the ease of working in there. icon_wink.gif

#19

Originally Posted By: rmoore
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In any case, I doubt that tracing a wire in a “bundle” is much easier than a “floating” messy one. I would imagine that most electricians, at least those that are still with us, double-check for current after throwing a breaker.


Even though I have very detailed (and accurate) labeling on my own panel, I'm still way too scared ![icon_eek.gif](upload://yuxgmvDDEGIQPAyP9sRnK0D0CCY.gif) of electricity to simply assume I've turned the right breaker off.

--
Richard Moore
Rest Assured Inspection Services
Seattle, WA
www.rainspect.com

#20

Originally Posted By: jtedesco
This post was automatically imported from our archived forum.


rmoore wrote:
Here?s the code section.
Quote:
NEC 312.8 Enclosures for Switches or Overcurrent Devices.
Enclosures for switches or overcurrent devices shall not be used as junction boxes, auxiliary gutters, or raceways for conductors feeding through or tapping off to other switches or overcurrent devices, unless adequate space for this purpose is provided.

The conductors shall not fill the wiring space at any cross section to more than 40 percent of the cross-sectional area of the space, and the conductors, splices, and taps shall not fill the wiring space at any cross section to more than 75 percent of the cross-sectional area of that space.


This was discussed over at that ?other site? some time ago. The fill rate intrigued me so I did a little ?research? and came up with the following...

The clear side wiring space, either side in my large 200-amp Square-D appears to be about 3" x 3" or 9 square inches. Doing some math on #12 wires, at a generous 1/8" diameter including insulation, it would take about 90 #12 to have a total cross section of 1 square inch. 40% of 9 sq" is 3.6 sq". 3.6 x 90 = 324 #12 conductors! Either side!

Clearly, that is a ridiculous example, but I can't find fault with my math. Even if you substitute much bigger #4s for the #12s it still comes to over 40 #4 wires, each side (equally silly).

We?ve all seen messy wiring in panels that appear at first glance to be overfilled. That wiring, like trees, is probably 90% air (although I can hit the 10% with a golf ball 100% of the time). ![icon_sad.gif](upload://nMBtKsE7kuDHGvTX96IWpBt1rTb.gif)


Richard:



The rule being discussed needs to be clarified and will be discussed during the meetings for the 2008 ROP.

--
Joe Tedesco, NEC Consultant

www.nachi.org/tedescobook.htm