Panelboards and "skirts"

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augie47 said:
based on TN State Code:

ELECTRICAL INSTALLATIONS CHAPTER 0780-2-1
0780-2-1-.03 APPROVAL OF ELECTRICAL PRODUCTS.
(1) Approved Testing Laboratories.
(a) The State Fire Marshal will accept as satisfactory (when properly installed or used) materials,
equipment, devices, or applicants which:
1. Bear a label, symbol, or other identifying mark of one of the following independent
(NRTL listings).
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Gus, your quote says that in TN an NRTL listed product must be accepted. I do not see where it says an unlisted product must be rejected.

FWIW, I would not doubt that in Wisconsin at least 75% of industrial and large commercial projects have unlisted gutters and wireways which have been approved by the AHJ.
 
jim dungar said:
Gus, your quote says that in TN an NRTL listed product must be accepted. I do not see where it says an unlisted product must be rejected.
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and I didn't say I would reject it. I said,I would not approve it. :)
jim dungar said:
FWIW, I would not doubt that in Wisconsin at least 75% of industrial and large commercial projects have unlisted gutters and wireways which have been approved by the AHJ.
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and I quoted TN State Code not Wisconsin.

There are a number of facilties that "custom build" wireways and gutters used in this area also, and they have the ability to affix a NRTL lsiting.
With that availability, I see no reason to accept the liability to "approve" a non-listed product.
 
Now that I think about it, I have installed "skirts" under generator connection boxes because the 4" LT flex would have been about 12" long and might as well been rigid pipe into the box.

We cut out the bottom of the connection box and had a 4 sided skirt made up with a removable cover and painted it to match the generator.
We even had a piece of rubber along the bottom to help keep dirt out.
The conduits had bonding bushing installed on them.
 
What is a metal wireway?
It is a few panels of metal that meet certain minimum standards for construction. There are countless shops in our area that custom build wireways.


I am not sure what is seemingly wrong with this install. How about transformers where wireways are installed, cutting the side of the transformer enclosure.
 
augie47 said:
Pierre,
I hope I am not approaching this, or any other inspection, with a "closed mind" attitude. I try hard not to do that. I agree, we must be "open" to new ideas. Not to beat a dead horse, but in this case it seems to me that the contractor could use: (a) an acceptable practice to terminate the conduits directly in the panel or (b) purchase "lsited" auxiliary gutters or j boxes to accomplish what seems to be the same goal.
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Augie
I may have posted in haste, I was not judging your character, I think you have done a pretty good job since you have been on this site, to show us all that you have a great character... so my apologies if I have done so.


I am probably more confused by the concern than anything else, that is all. Remember (sometimes I myself forget :wink:) that we see/install some portions of our work differently in different parts of the country.
 
I would never allow someone to cut off the bottom of the cabinet and put a "skirt" under it. I would cite 110.3(B) for cutting the cabinet bottom off, and I would cite 300.12 for mechanical continuity of the raceways to the enclosure.
 
ryan_618 said:
I would never allow someone to cut off the bottom of the cabinet and put a "skirt" under it. I would cite 110.3(B) for cutting the cabinet bottom off, and I would cite 300.12 for mechanical continuity of the raceways to the enclosure.
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What if I remove the screws connecting the bottom portion of the cabinet. Then construct an auxiliary gutter in accordance with the construction specs of 366.100 and attach that to the bottom of the cabinet. And finally re-install the bottom of the cabinet in the bottom of the gutter and attach the conduits?

I have seen this install before. In essence you are extending the wiring space within the cabinet. This install had a screw mounted cover that went over the gutter potion.

Chris
 
ryan_618 said:
I would never allow someone to cut off the bottom of the cabinet and put a "skirt" under it. I would cite 110.3(B) for cutting the cabinet bottom off,
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So I assume you fail any installation that has field punched KOs or wireway adapters or Robertson duct cut into the panel?
 
Ryan
I am with Bob in response to your last post.

Think of all the installations where there have been field modifications to enclosures.

In general, as long as there is no enclosure structural degradation, I am not sure what the issue is.

What about a transformer where one cuts the enclosure to install a wireway as opposed to just conduit?

What about "tophats" installed on switchgear, where the installer cuts the enclosure, thereby making it somewhat easier to enter the conductors to the enclosure?
 
I am visualizing a flush mounted panel in a stud wall with the bottom cut out of it. The electrician cuts out the bottom of the cabinet and puts sheet metal down to the bottom of the wall so he doesn't have to punch the enclosure. I would reject this.

If you are talking about making a wireway, and connecting the wireway to the enclosure, then I would buy it. I don't see that as being what the OP described however, unless I am missing something.
 
raider1 said:
What if I remove the screws connecting the bottom portion of the cabinet. Then construct an auxiliary gutter in accordance with the construction specs of 366.100 and attach that to the bottom of the cabinet. And finally re-install the bottom of the cabinet in the bottom of the gutter and attach the conduits?

I have seen this install before. In essence you are extending the wiring space within the cabinet. This install had a screw mounted cover that went over the gutter potion.

Chris
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I would even buy it (if I were an inspector) if the bottom portion was fabricated - just that it is closed... While I am not sure this is being enclosed in a wall - but even then if there were say a fault, and some sparks/molten metal decided to fall down, it could bounce out is there was any gap at the bottom.... IMO the whole point of having an "enclosure" is to 'enclose'....

That said I do a number of things that come close to this - but different. J-boxes or Gutters with 3-4 (2-3") nipples right into the panel. With the J-box option you can often stuff it pretty full if say branches under #4 are in there, and/or have the feeder for the panel go through it as well... Since it is not a wireway you are not limited to 30 CCC's.
 
Pierre C Belarge said:
Augie
What happens sometimes is we see an installation practice that has never been used in our jurisdiction/locale.
Because it is different and seems like an issue, our brains have a hard time wrapping around the idea that the installation is code compliant. Take out of the equation that we do not like something and then it gets easier to be open minded.
Opening the bottom of the panel enclosure is not to much different than having many cables or conduits entering the enclosure. As long as the panel is not structurally damaged and the bonding is satisfactory. I do not sse an issue.
As a matter of fact, I see a code compliant installation that may give some wiring relief to an installer in regards to the ease of access for wiring methods.
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These panel "skirts" or wireways are listed for its purpose. We did not just remove the bottom of a panel and manipulate this wireway to fit underneath this panel. This wireway is approved for use by the manufacturer of the panels. When the bottoms are removed, the wireway attaches to the panel with the factory screws. We even went as far as pulling the wireway specifics online from the manufacturers website with the inspector present.
Our intent of this wireway is as stated above. We also take care of managing the conductors so that they adequate space from the front cover.
At this point, both the inspector and I have came forth with enough information as to not find a clear cut answer. There are some very good points here and once again, I appreciate any thoughts on the subject.
And yes, there are a couple different methods to alleviate this issue. Unfortunately, there are several buildings on my project which are completely terminated.
 
Missed one

Missed one

I wanted to make it clear just in case I haven't in the previous responses. I read that some of the responses are under the wrong assumption.

The bottom of these panels are removable by removing 7 sheet metal screws. Once the bottom is removed,the wireway or "skirt" mates with the panel with no difficulty. The wireway even has the holes pre-drilled in order to attach it to the panel. All sides of the panel and wireway are flush and maintains a secure and mechanically sound bond so to speak. I just wanted to clarify that we didnt let someone attack the panel with a sawzall. I hope this helps any confusion.
 
riverjig87 said:
I wanted to make it clear just in case I haven't in the previous responses. I read that some of the responses are under the wrong assumption.

The bottom of these panels are removable by removing 7 sheet metal screws. Once the bottom is removed,the wireway or "skirt" mates with the panel with no difficulty. The wireway even has the holes pre-drilled in order to attach it to the panel. All sides of the panel and wireway are flush and maintains a secure and mechanically sound bond so to speak. I just wanted to clarify that we didnt let someone attack the panel with a sawzall. I hope this helps any confusion.
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What issues does the inspector have with the installation as you have described it?
 
Here it is

Here it is

The inspector has decided that the panelboard installation is a "floor-standing panelboard". His reasoning for this is by adding the panel skirt, it extends the panel to the floor. I have shown him the definition of floor standing panelboard but he doesnt interpret this installation as I do. Even though the panel is bolted to the wall along with skirt, and by no means does the floor act as a support in any way, he remains steadfast on his interpretation so far. These panels have already been terminated and there are about 15 completed. By identifing this installation as such, Article 408.5 of the 2005 NEC directly applies to us. Unfortunatly, the foremen in the other buildings failed to trim down their branch circuit stubs and a majority are 4"-6" above the pad. Im trying to get as much information, even though its starting to appear we might be trimming these conduits, so that right or wrong I am well prepared.
It all comes down to saving some possible lost hours.

1. Is our panel considered a "similar enclosure" as read in the 1st sentence of this article?

I can interpret that sentence to be directed at switchgear and any other piece of equipment that is free standing. I can understand in that application the difficulties that can arise from conduits being to high. I.E. interfering with the switchboards frame, coming in close proximity of bussing, etc.

The bottom of our panels are at minimum 4 feet above finished floor.
Whats your take?


408.5 Clearance for Conductor Entering Bus Enclosures

Where conduits or other raceways enter a switchboard, floor-standing panelboard, or
similar enclosure at the bottom, sufficient space shall be provided to permit installation of
conductors in the enclosure. The wiring space shall not be less than shown in Table 408.5
where the conduit or raceways enter or leave the enclosure below the busbars, their
supports, or other obstructions. The conduit or raceways, including their end fittings,
shall not rise more than 75 mm (3 in.) above the bottom of the enclosure.
 
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riverjig87 said:
The inspector has decided that the panelboard installation is a "floor-standing panelboard". His reasoning for this is by adding the panel skirt, it extends the panel to the floor. I have shown him the definition of floor standing panelboard but he doesnt interpret this installation as I do. Even though the panel is bolted to the wall along with skirt, and by no means does the floor act as a support in any way, he remains steadfast on his interpretation so far. These panels have already been terminated and there are about 15 completed. By identifing this installation as such, Article 408.5 of the 2005 NEC directly applies to us. Unfortunatly, the foremen in the other buildings failed to trim down their branch circuit stubs and a majority are 4"-6" above the pad. Im trying to get as much information, even though its starting to appear we might be trimming these conduits, so that right or wrong I am well prepared.
It all comes down to saving some possible lost hours.

1. Is our panel considered a "similar enclosure" as read in the 1st sentence of this article?

I can interpret that sentence to be directed at switchgear and any other piece of equipment that is free standing. I can understand in that application the difficulties that can arise from conduits being to high. I.E. interfering with the switchboards frame, coming in close proximity of bussing, etc.

The bottom of our panels are at minimum 4 feet above finished floor.
Whats your take?


408.5 Clearance for Conductor Entering Bus Enclosures

Where conduits or other raceways enter a switchboard, floor-standing panelboard, or
similar enclosure at the bottom, sufficient space shall be provided to permit installation of
conductors in the enclosure. The wiring space shall not be less than shown in Table 408.5
where the conduit or raceways enter or leave the enclosure below the busbars, their
supports, or other obstructions. The conduit or raceways, including their end fittings,
shall not rise more than 75 mm (3 in.) above the bottom of the enclosure.
Click to expand...

You might try contacting the manufacturer of the panel and wire way to see if they would give you a letter stating that it is not a "floor mounted" panel with the "skirts" attached to it. If you could it may qualify as part of the "installation instructions". Or ask for a formal review of this by the AHJ.
 
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