110.26 (F) Dedicated Equipment Space headache! Please explain the logic!

[Strathead]

I was wrong, again. I hate it when that happens. In a facility where the sewer pipes must be where they are, my main switchboard grew and placed the corner under it. The height is like 13 feet off the ground, but my gear is 92" plus the pad I think so at least 8 feet off the ground to the top. Nothing at all comes out of the top.

So, my mistake I thought as long as the foreign system was protected and didn't violate the headroom 110.26(E) it could be above the gear. My inspector astutely informed me that the section states the systems are allowed, "above the dedicated equipment space" only. 110.26(F)(1)(b). That just makes zero sense to me.

So it is OK for a structural ceiling to be right above the piece of equipment if over 6 1/2', but a pipe protected by a metal pan can't be 3 or 4 feet above the panel? Yet 6 feet above the panel it is OK. Someone smarter than me, please explain the logic.

 

[jtinge]

What code cycle are you on? Dedicated Equipment Space requirements for 2014 are 110.26(E).

That being said, there is a good one and a half page explanation of dedicated equipment space, with figures, after 110.26(E)(1)(d) in the NEC Handbook.

 

[charlie b]

I think the idea is to allow room for the future installation of conduits. That is why the rule applies to switchboards, switchgear, panels, and MCCs, and does not apply to transformers, VFDs, disconnect switches, or enclosed breakers. For those items, once they are installed, there will be no future conduits. The rule reserves the first 6 feet above the panel so that you can install conduits without having to fight your way past ductwork or pipes. If there isn't at least 6 feet above the top of the panel because the room is too short, so be it. In that case, you can't put a duct or pipe above the panel, and you will have to do your best in installing that future conduit. The NEC will not dictate to architects what they can do about floor heights. All the NEC can do is give us as much room as is available, up to the first 6 feet, for our future use.

 

[charlie b]

What code cycle are you on? Dedicated Equipment Space requirements for 2014 are 110.26(E).

I think Strathead knew that. He changed subjects mid-sentence, and cited 110.26(E) in the context of headroom.

 

[Strathead]

I think Strathead knew that. He changed subjects mid-sentence, and cited 110.26(E) in the context of headroom.

No, Charlie, I was using 2008, but don't know why I had 2011 right under it and they changed to section (E) in that code cycle. No significant changes were made to the wording, between. Can't speak for 2014. The specific job is covered under 2008 code and we have switched to 2011 for all new jobs since January 1.

 

[Strathead]

I think the idea is to allow room for the future installation of conduits. That is why the rule applies to switchboards, switchgear, panels, and MCCs, and does not apply to transformers, VFDs, disconnect switches, or enclosed breakers. For those items, once they are installed, there will be no future conduits. The rule reserves the first 6 feet above the panel so that you can install conduits without having to fight your way past ductwork or pipes. If there isn't at least 6 feet above the top of the panel because the room is too short, so be it. In that case, you can't put a duct or pipe above the panel, and you will have to do your best in installing that future conduit. The NEC will not dictate to architects what they can do about floor heights. All the NEC can do is give us as much room as is available, up to the first 6 feet, for our future use.

That is the only explanation I can come up with, but it seems way outside the scope of the NEC. That would be like requiring 4-3/4" conduits stubbed up in any flush mount panel for "future" wiring. In my case this is a free standing switchboard that has zero room for new circuit breakers so that reasoning would be arbitrary at best.

 

[charlie b]

I would not call it arbitrary. If you got no room, then you got no room. But if there is room, we get first dibs on it. It is as simple as that.

 

[tom baker]

Put in a structural ceiling below the sewer pipes. We did that once with a drywall lid above a ATS. The ATS had to be installed under existing air ducts

 

[Strathead]

I would not call it arbitrary. If you got no room, then you got no room. But if there is room, we get first dibs on it. It is as simple as that.

I call it arbitrary because it doesn't fit in to the stated goals of the NEC. " This code is not intended as a design specification" for one. Again no different than requiring spare conduits, or room for another panel. It is also arbitrary because the bend radius of a 4" elbow is like 16" so 24" of space would be more that enough for even a large piece of gear.

Please understand that I am not arguing that you are wrong. And especially not arguing that any good electrical installation takes many things in to account that the code doesn't require. This code however doesn't fit for the above reasons, so I feel there is either a valid reason I am missing, or this is one of those example where the code is just wrong.
Give me one good reason why a structural ceiling is OK, (especially one not constructed watertight) is OK, but a pipe protected by a metal pan is not.

 

[Strathead]

Put in a structural ceiling below the sewer pipes. We did that once with a drywall lid above a ATS. The ATS had to be installed under existing air ducts

Our inspector (thank you sir) allowed us to put a drywall soffit around the pipes. While I don't know the legal definition of a structural ceiling, I doubt this is one. Do you know the definition of a structural ceiling?

 

[charlie b]

Do you know the definition of a structural ceiling?

110.26(E)(1)(d) gives a fairly good conceptual description. It has to add structural strength to the building structure. Drywall will not accomplish that mission, and surrounding a pipe with anything will not constitute a "ceiling."

 

[Strathead]

110.26(E)(1)(d) gives a fairly good conceptual description. It has to add structural strength to the building structure. Drywall will not accomplish that mission, and surrounding a pipe with anything will not constitute a "ceiling."

And what electrician know what "adds structural strength" to the building structure? Again mot arguing with you, as much as frustrated with the arbitrary nature of this code section

 

[don_resqcapt19]

And what electrician know what "adds structural strength" to the building structure? Again mot arguing with you, as much as frustrated with the arbitrary nature of this code section

So submit clear and consise wording to fix it for the 2020 code. You have until early November, 2017 to work up your "public input" (formerly known as a proposal).

 

[Strathead]

So submit clear and consise wording to fix it for the 2020 code. You have until early November, 2017 to work up your "public input" (formerly known as a proposal).

Don, until I understand the logic to the original section, I am not going to propose a change. This section has survived at least 4 code cycles that I know of, but I never knew it stated "above" the dedicated space, I always thought protection was need if it was in the dedicated space. I am sure I have seen this section violated at least four or five times.

The one that comes clearly to mind is a main electrical room in the basement of a high rise. There was drain piping and ductwork run all over the place, with metal pans everywhere. The ceiling was no more than 12 feet tall. I see absolutely no issue that has to do with the intent of the NEC that makes this installation a problem. The rule seems to have nothing do with practical safeguarding at all. The only marginal thing could be water dripping down on a panel, but if so, it is very poorly written because a pressurized pipe can be run 2 inches in front of the panel above it, and a metal pan is no more or less effective 6 feet above the equipment than it is 4 feet above the equipment.

So, I am still looking for the logic.

 

[kwired]

110.26(E)(1)(d) gives a fairly good conceptual description. It has to add structural strength to the building structure. Drywall will not accomplish that mission, and surrounding a pipe with anything will not constitute a "ceiling."

And what electrician know what "adds structural strength" to the building structure? Again mot arguing with you, as much as frustrated with the arbitrary nature of this code section

The logic seems clear until you run into those occasional situations where something isn't allowed by the letter of the law, yet you ask what could possibly go there in the future at least without making major changes.

Real estate and the electrician getting first dibs on the space? What about when electrician is trying to find a place to locate a panelboard, switchboard, motor control center in existing construction and there is just one little item that doesn't really seem to be much of an issue in the dedicated space? Yes we do need consistency in the rules so that makes it harder to make exceptions, other then for some things that are very common - like the mentioned suspended ceiling panels being allowed in the dedicated space.

Lets not forget the dedicated space is also below the equipment and I have run into problems there as well. Been in basements of dwelling units before where maybe a sewer pipe runs horizontally on a wall where it would be good place for panel but that drain pipe below the panel is not allowed even though it is very unlikely one would ever run any new circuits from the panel down to the floor in such a situation Non dwelling with same situation - maybe slightly more chance of running such a circuit - but still not too likely unless the building is under major renovation, change of occupant type or something big like that.

New construction is easier to understand - we need to design things to meet the rules. Existing construction there about has to be an ability to bend some rules or you essentially turn it into new constuction - which sometimes isn't all that bad either.

 

[GoldDigger]

T

Lets not forget the dedicated space is also below the equipment and I have run into problems there as well. Been in basements of dwelling units before where maybe a sewer pipe runs horizontally on a wall where it would be good place for panel but that drain pipe below the panel is not allowed even though it is very unlikely one would ever run any new circuits from the panel down to the floor in such a situation Non dwelling with same situation - maybe slightly more chance of running such a circuit - but still not too likely unless the building is under major renovation, change of occupant type or something big like that.

I guess I would have to build out a support board for the panel such that the drain pipe is behind it instead of directly under it. The conflict with running conduit down the wall will be unchanged but the letter of the Code will have been met.
Unlike the working space, the dedicated space does not extend either in front of or behind the equipment.

 

[Fulthrotl]

Our inspector (thank you sir) allowed us to put a drywall soffit around the pipes. While I don't know the legal definition of a structural ceiling, I doubt this is one. Do you know the definition of a structural ceiling?

it's funny... if you google that, you end up right back here, 13 years ago.

http://www.mikeholt.com/forum/Forum1/HTML/003766.html

 

[kwired]

I guess I would have to build out a support board for the panel such that the drain pipe is behind it instead of directly under it. The conflict with running conduit down the wall will be unchanged but the letter of the Code will have been met.
Unlike the working space, the dedicated space does not extend either in front of or behind the equipment.

Exactly what I have done a few times - but was rather pointless if you ask me, hard to write code to fit every situation though so they write it to fit the majority of situations that are out there.

One other example that an inspector once let me get by with was a situation where we were mounting a panel in an apartment flush in an existing wall. There was a hydronic baseboard heater at the bottom of wall and really no good place to put panel that would be clear space other then a hydronic heater. This was a building on grade - concrete floor, not likely any future lines will run from panel to/beyond the floor without being a major renovation type of thing anyway, and though it was technically in the working space - who stands that close to the wall when working in a flush mounted panel?

 

[Carultch]

Exactly what I have done a few times - but was rather pointless if you ask me, hard to write code to fit every situation though so they write it to fit the majority of situations that are out there.

One other example that an inspector once let me get by with was a situation where we were mounting a panel in an apartment flush in an existing wall. There was a hydronic baseboard heater at the bottom of wall and really no good place to put panel that would be clear space other then a hydronic heater. This was a building on grade - concrete floor, not likely any future lines will run from panel to/beyond the floor without being a major renovation type of thing anyway, and though it was technically in the working space - who stands that close to the wall when working in a flush mounted panel?

If the only intent of "dedicated space" is for the potential of future conduits, why not just make it 3 ft, instead of 6 ft, which is extremely more than necessary? 3 ft is plenty of room for any bends or L-bodies of just about any trade size. Plus, how often do you even connect a 4 inch conduit to a 100A panelboard?

The chance of a future 4" conduit is pretty rare to begin with, as most future work would likely be smaller sizes, and planning for future expansion is not in the scope of the NEC.

The way they present the concept of dedicated space makes you think that its intent is to avoid damage to your equipment from leakage of foreign systems. Or to avoid cheating the clearance and maintenence requirements for the foreign system equipment.

 

[kwired]

If the only intent of "dedicated space" is for the potential of future conduits, why not just make it 3 ft, instead of 6 ft, which is extremely more than necessary? 3 ft is plenty of room for any bends or L-bodies of just about any trade size. Plus, how often do you even connect a 4 inch conduit to a 100A panelboard?

The chance of a future 4" conduit is pretty rare to begin with, as most future work would likely be smaller sizes, and planning for future expansion is not in the scope of the NEC.

The way they present the concept of dedicated space makes you think that its intent is to avoid damage to your equipment from leakage of foreign systems. Or to avoid cheating the clearance and maintenence requirements for the foreign system equipment.

I can agree to most of what you said - can also add if leakage is the problem - there are other enclosure designs besides NEMA 1:happyyes:

The dedicated space requirements has been there for a long time with only minor if any changes to it.