I have a large service panelboard at a BP gas station and convenience store. All the conduits from the island dispensers run back to the open bottom floor mounted service panelboard on the inside, and the seal off fittings are the first fittings located just above the concrete slab. I can't find a code section that would not permit this installation.

1. The panelboard is not an explosionproof enclosure.
2. The panelboard is located in an unclassified area.

What code section will I use to reject the seal off's for being inside the panelboard in article 500 and 501?

Mike, I just got in from the field so I have to clean up and then I will go out and get my code book and take a stab on this one.

What is immediately coming to my mind is not in 500 or 501. It is somewhere in Switchboards and Panelboards. There can only be a 3" rise inside a switchboard or panelboard and I do believe that the code article stipulates that fittings are most definitely included in this measurement. You will have to double check me.

Just quick thinking. I could be wrong but that's my immediate thought. I will post back later as soon as I can.

I believe Nick is refering to Section 408.10

Yup, that's the one. I just looked it up and it applies to switchboards, floor-standing panelboards, or similar enclosures. The seal off is a fitting so I would take a measure and if it is more than 3" rise inside the enclosure, then I would tag the job. It might be close, I don't know. Also keep in mind that the minimum wiring space (assuming insulated busbars) shall not be less than 8" from the bottom of the enclosure and bussbars, their supports, or other obstructions, so that is something that might apply.

I will start looking in 500 and 501 also.

Well, I know I always say this, but first I would double check the approved set of plans. A gas station is usually done by an engineer who stamped the plans...see if the contractor complied with the approved drawing, or if he/she took it upon themselves to install the seal offs inside the panelboard on their own.

Then, I went to 500, 501 could find nothing.

Then, I went to 250 because the seal off fitting needs to be grounded in my opinion. 300.10 may also be useful. I don't think 250.86 would apply because one will argue that a seal off is not an enclosure or raceway. But, the term equipment by definition applies to fittings and, would not 250.110 condition 1 apply? I think this contractor screwed up because the only way to bond that fitting is with a short rigid nipple and a bonding bushing (MIG) and by that time they will exceed the 3" maximum rise.

Opinions....?


PS - (off the subject) Since this is a gas station a quick reminder to everyone that the car-vacs at gas stations usually have no listing whatsoever, so be sure to check for a listing at final inspection. A field listing may be in order.

Yep we agree about the 3" rise for the fittings in the panelboard, and the requirement for bonding. That is taken care of before final so they end up being ok.

But again, do we have a code section that would prohibit the seal off fittings from being inside the panelboard per article 500 or 501?

After much research I think that it’s ok.

Mike I am trying to upload the photos you sent but my server is not responding at the moment so I will try again later.


question:
how are they bonding the seal offs?

Here are some photos of the installation that Mike asked me to post:

A nipple will be installed with a bonding bushing and a bonding jumper.

I'm still scrounging around for something in 514 to prevent this installation, but for now how about using 300.15(F)

?

300.15(f)? Maybe I'm missing something since its Monday morning about 7:00 am, but how can I apply that?

In my opinion, this is a terrible installation and I worked gas station and refinery jobs up north for numerous years and would never install a seal off in a panel. I can't tell if the bottom threads in the picture are into the panel but still wouldn't want to depend on the 5 full threads being made up. And it is proven gases do pass through the seals to a certain extent especially on larger conductors. The purpose of the seal is to prevent gases from passing through one portion of the system to the other.Article 501.5 (A)(1) states conduit seals shall be installed within 18 inches of enclosures not inside.

Nick, Art 514.9 (B) Kicks you back to 501.5 regarding sealing at the boundry
and even though the panelboard in the station is not in a hazardous location it still requires a seal to prevent gas migration into the panel, so as I said before this is just a bad installation
See the picture in the handbook page 703.

I threw 300.15(F) out there because it says that a fitting has to be accessible after installation. You are going to tell me that it is accessible. Right?

I don't have my code book with me right now so cut me some slack, but it looks like that installation will not permit the removal of a seal off. They are crammed one next to the other. If one needed to be tightened more (good point eman, about the threads), I don't see how you could do it.

I agree this is a terrible installation.

The more I get into this the more I don't like this installation. The manufacturers of the fittings spec out a "turning radius" for the fitting. The fittings in the picture no longer have this, so possibly 110.3(b) could come into play if the turning radius has to be maintained.

I still don't think that they are accessible after installation and now I am wondering how they got them in that close to begin with.

Also if the gas station changes hands at some point and there is a need for a retrofit, it could be extremely impossible given this installation.

That turning radius thing begs the question, how did they put this thing together in the first place. Were the pipes all made up in the panel before it was installed and they poured the concrete floor around it?

The point gentlemen is the sealoff's don't go in the panel period. If any gases get through don't light a cigarette near those contactor's.

I don't like it, but so far I don't have a code section to prohibit it since it's not an explosionproof enclosure, it's not in a classified location, and complies with the sealing requirements at the boundary in 501.5(a)(4),

Seal off fittings will leak, around the threads, the compound, and even through the internal strands of the inner core of the cable and conductors themselves. But as stated in the Handbook on page 635 of 501.5:

In addition we contacted NFPA and they came back and said that they didn't like it, but also there was no violation of code, and Chapter 5 didn't apply to this specific problem of the seal off fittings being located inside the panel.

So than if that is correct, and there is no code section that applies, how can it be rejected! The only to solve this problem is by a code change to the 2008 NEC. But without proof there is a problem by some documented occurrences NFPA won't change it!

Go figure!

P.S. Is this just another case of since I've never seen this it must be wrong? Or is this being installed in other parts of the US by The BP company without problems?

Mike, 514.9 (B) requires seals be applied per 501.5. Then 501.5 (A) (1) for entering enclosures conduit seals are required within 18 inches from the enclosure not within the enclosure. The picture in the handbook shows the proper installation of the seal's, and my years installing wiring in hazardous locations we would never install any other way. As per the fine print in the handbook "Panel boards are generally located in a room classified as a non-hazardous location;however, any conduit coming from the dispenser or passing under the hazardous (classified) location boundries from the dispenser or tank filled pipe would require a seal at the panelboard location to minimize the likelihood of gas migration into the remote location." Any way if you contacted NFPA I don't know what else to say except bring change by code committee.

True the code sections you point out are correct for enclosures that are required to be explosionproof because they are located in classified areas. See quote 501.5(a):

The point NFPA made is if the panelboard in located in a unclassified area, the enclosure is not required to be explosionproof . Therefore the rules of installing a seal off fitting within 18" of the panelboard enclosure per 501.5(a) or (b) do not apply.

The only code rule would be 514.9(b) that would require a seal off, to be the first fitting, and located at the boundary, which in this case is the concrete slab that the listed floor mounted panelboard is installed on. Once it's sealed at the boundary, it's all unclassified now.

I think we are dealing with a problem that wasn't thought of, and that's why the NEC doesn't address this specific problem.

I would have never dreamed of putting a seal off in a panelboard. But BP sure did their homework on this one.

Mike,

How would you test the seal off fitting, if it is wrench tight or not? You can't. I still say it's not accessible, how they installed it.

I think that is a contactor's responsibility making sure the fittings are tightened properly. All points that conduits in classified locations are connected to explosionproof enclosures, fittings, etc need to be made up wrench tight with 5 threads. (Except the 2005 code only requires 4 1/2 threads. Ha Ha!) I don’t check those. Just like all terminal lugs and conductor termination points in paneboards, require that they are torqued. As an inspector my jurisdiction doesn't provide the tools to check those things.

Let me ask, does the code in 501.5(c)(1) when it requires the seal off fittings to be accessible, to actually be removable? Or do they only have to be accessible so the conductors may be pulled, compound poured, or later re-poured, and checked through the access plug?

I'm not giving up on this. Now it's a quest. I will find something -- something good -- code solid that you will agree with me on. I just haven't found it yet. I still don't agree that they are accessible but that may be my interpretation and not yours (understood).

Then we will see how BP handles its Big Problem.

Good that' what we need.....something!

I can hear you giggling because you already know that it isn't in there......here is what I would do if it were me:

1) I would request a sealed letter from the designer of record (for a gas station it's probably an engineer) that states that he has no problem with the sealoffs being inside the panelboard. I would do this because it puts the responsibility of design back on the designer. It also takes any burden off of the inspector for an apparent lack of code language to prevent this from happening. I would want something from the degigner stating the fact that he/she is aware of how it is built. Maybe the plans already show them in there, I don't know, but I would be surprised if they did.

2) Come final inspection I would be waiting there with my tape rule. If the bonding bushing puts the sealoff at over 3" then I would fail the job. I would not accept 3.5". If that is the only way I could prevent this installation then I would use it. The code says 3" and the code is the code is the code.

You guys have a great Christmas if there are no more posts until then. In the meantime I'm still lookin' for that perfect code.........

Yep..did just that..the plans actually showed the seal off fittings under the panel on the outside just like you would think. So we requested a plan revision with a sealed letter from the engineer showing the seal off fittings inside the switchboard.

Along with that we have some e-mail's from some code experts (the big guns) telling us that in their opinion it's ok.

All of that information goes into the file, and shows that we extended ourselves to confirm the correct code interpretation. Can't do more than that. We even reviewed the 2005 to see if there changes that might effect the installation.

Looks like you've covered yourself and your jurisdiction from all angles. Good job Mike. I too would have to pass this. I was hoping to find something in 314 but it's just not in there. I don't like the fittings inside because other than taking up gutter space, the fittings don't permit future expansion because they can't be changed at this point. I'm not sure if 90.8 can apply in any way with this situation.

I do not know if the manufacturer of the sealoff fitting states that turning raduis must be maintained or not, and I guess they don't address it.

Sidebar: Seal off fittings come in a wide variety of materials depending on use. See commentary below that I got from an electrical magazine:

What choices do you have? Although their purpose is the same, sealing fittings come in a wide variety of designs to meet the exact requirements of specific applications. Besides being available in designs for vertical and horizontal conduit runs, sealing fittings come in different materials. Grayloy(tm) iron sealing fittings; also known as "breakout" seals; are favored in applications where you may want to fracture and remove a sealing fitting when retrofitting a conduit system. Malleable iron sealing fittings are ideal for the most demanding hazardous location. Extremely strong, malleable iron has a high tensile strength that enhances performance because it will not fracture under excessive internal or external pressures. The higher yield strength of malleable iron also permits the product to have a thinner cross-section, which results in a closer turning radius for easier installation.

Happy New Year everyone. Well I hate to give in to this situation but after talking to an Appleton engineer I guess I have to. He agrees with me that this in the very least is not a normal trade practice and the engineer,with the wording of the national electrical code,can circumvent the proper trade practice of seal off installations. It even shows the proper installation in the handbook in article 514. I guess we have to push to get this rewritten in the code.

One more thing as per Nick said I will be scrutinizing any other option to turn it down if i can.

In speaking with one of the experts on code panel 14 the reason why this is not a problem with gas stations is because the vapor leakage is not pressurized or under pressure, so the vapor leakage under normal atmospheric pressure differentials is minimal and dissipates quickly.

Evidently this installation is quite common and is, and has been used in many other states.

So don't look for a change, since the code panel has seen this specific installation and they don't think it's a problem.