Stamping Letter From a Manufacturer

[Sparky1981]

I worked on a project that had a small shade structure on the site. The contractor used the tubular steel frame as a raceway for the lighting and receptacle branch circuits. The inspector wont sign off until I stamp and sign a letter from the manufacturer, the wording is below.

"For the past 27 years we have used our tubular steel frames as an electrical “conduit” or raceway by providing conduit stub up holes in the column base plates, holes in each beam end plate and hand holes throughout the frame to pull the wires through the inside of the frame to outlets and light locations. The use of our frame, which is free from any obstructions, burrs or other damaging edges is approved for running electrical wires. This has worked very well for many years and eliminates unsightly exposed conduit which otherwise would be attached to the outside of the columns and frame members. The outlets are typically recessed flush with the columns and the light fixtures or other electrical devices are mounted directly to our frames (ridge beams) or compression rings at the peak of the structure. This method makes for a very safe and esthetic electrical installation when complete. The structure is grounded by virtually being bolted to each footing but a ground rod or wire may be added as desired and attached to a column.

With well over a thousand installations we have had very few problems or issues from building departments across the U.S. and Canada.

If anyone has questions feel free to call us at the number listed below during business hours."

In my mind using the tubular steel should be fine as there is nothing else in it. However unlike conduit is it UL listed for it? I hate to be a pain to the contractor but I am hesitant to stamp this as other than this letter I don't a reference to tell me this is ok.

Thoughts?

 

[dkidd]

is approved for running electrical wires.

Approved by whom? Its your license. Do you work for the manufacturer?

 

[Sparky1981]

Thats my problem. I am looking for something in the NEC that allows it. Otherwise I am handcuffed, I do not work for the manufacturer, so a letter saying its fine from the manufacturer to me is not enough for me to stamp.

 

[Ingenieur]

Have the conractor get the letter sealed

 

[jumper]

I am a bit confused. Does this contraption have a UL or other NRTL listing or not?

 

[Sparky1981]

Contractor is the one asking me to seal it.

I have request that manufacturer send backup for their statement saying that the tubular steel is approved for use as an electrical raceway.

 

[charlie b]

As a PE, you are not allowed to sign and seal a document that was prepared by another person who was not, at the time, working under your supervision. But there is an option that is available to you. Write your own letter that comprises a report that documents your review of the manufacturer's document. The work that was done by you (or under your supervision) was the task of performing that review. That way, you are not taking responsibility for what the manufacturer wrote. You are only taking responsibility for your review, and your report of the results of that review.

By the way, it is clear that the manufacturer's representative who wrote that document does not understand the concept of grounding or bonding. I infer that from their having mentioned a ground rod in the context of properly grounding their equipment. I suggest including, in your report of your review, a statement that the branch circuit's EGC will serve to achieve the required grounding.

 

[jumper]

Contractor is the one asking me to seal it.

I have request that manufacturer send backup for their statement saying that the tubular steel is approved for use as an electrical raceway.

Just a dumb bunny here, but I say:

Tell the contractor that you and the AHJ will only "approve" the installation of a listed piece of equipment and that it is the manufacturer's responsibility to get a NRTL listing.

My 2 cts.

 

[Sparky1981]

Correct Charlie. I had never considered stamping their letter. My intent was to do as you said, create my own document, but I want that document to be able to reference the NEC or a UL listing or something that says this is ok. I am in no position to determine what can and cant be used as conduit, thats not my expertise.

I also see what you are saying with my review however I am positive the inspector is looking for ME to stamp a statement that says running the conductors in the steel is approved. And unless I have a reference that tells me this is ok, such as the NEC, or UL, I can't make this call.

 

[gadfly56]

Correct Charlie. I had never considered stamping their letter. My intent was to do as you said, create my own document, but I want that document to be able to reference the NEC or a UL listing or something that says this is ok. I am in no position to determine what can and cant be used as conduit, thats not my expertise.

Ask the manufacturer for the UL listing number and download it from UL's web site.

 

[zbang]

Ask the manufacturer for the UL listing number and download it from UL's web site.

Or just ask the mfg for their own PE-stamped letter or drawing. I'd be surprised if the don't have a mechanical PE (which wouldn't apply here) at least on retainer, so they should understand the concept.

 

[petersonra]

I worked on a project that had a small shade structure on the site. The contractor used the tubular steel frame as a raceway for the lighting and receptacle branch circuits. The inspector wont sign off until I stamp and sign a letter from the manufacturer, the wording is below.

"For the past 27 years we have used our tubular steel frames as an electrical “conduit” or raceway by providing conduit stub up holes in the column base plates, holes in each beam end plate and hand holes throughout the frame to pull the wires through the inside of the frame to outlets and light locations. The use of our frame, which is free from any obstructions, burrs or other damaging edges is approved for running electrical wires. This has worked very well for many years and eliminates unsightly exposed conduit which otherwise would be attached to the outside of the columns and frame members. The outlets are typically recessed flush with the columns and the light fixtures or other electrical devices are mounted directly to our frames (ridge beams) or compression rings at the peak of the structure. This method makes for a very safe and esthetic electrical installation when complete. The structure is grounded by virtually being bolted to each footing but a ground rod or wire may be added as desired and attached to a column.

With well over a thousand installations we have had very few problems or issues from building departments across the U.S. and Canada.

If anyone has questions feel free to call us at the number listed below during business hours."

In my mind using the tubular steel should be fine as there is nothing else in it. However unlike conduit is it UL listed for it? I hate to be a pain to the contractor but I am hesitant to stamp this as other than this letter I don't a reference to tell me this is ok.

Thoughts?

I think it is a great idea and probably has worked well and quite safely for many years. having said that, I suspect it does not meet code if it is not listed as a raceway.

A solution to the problem would be to run UF cable instead of wires inside the tubular steel frame.

The guy is saying it is "approved". Maybe he means it is already listed. Or maybe he thinks he can approve it.

 

[charlie b]

I am a bit uncertain of how the NEC would treat this. A UL listing as an electrical raceway would close the deal, but I doubt that this framing system has been listed for that purpose. Here is where I am confused:

• 300.3(A) tells me that you can't run single conductors unless you are using a wiring method that is recognized in Chapter 3. I don't see anything in Chapter 3 that would match the description you have given us of this framing system.
• On the other hand, 300.4(B)(1) seems to allow certain types of cables to be run through factory-punched holes in metal framing members. Since that paragraph is part of Chapter 3, does that mean that Chapter 3 has recognized metal frames as an allowable wiring method?

The manufacturer's description of how well they smooth out the holes so that there are no burrs or damaging edges would not be enough to satisfy the requirements of 300.4(B)(1). They need to add listed bushings or grommets at every joint, and I don't think that is happening.

 

[steve66]

I think it is a great idea and probably has worked well and quite safely for many years. having said that, I suspect it does not meet code if it is not listed as a raceway.

A solution to the problem would be to run UF cable instead of wires inside the tubular steel frame.

The guy is saying it is "approved". Maybe he means it is already listed. Or maybe he thinks he can approve it.

I seem to run into this a lot. Clients, contractors, and vendors always seem to want to run power through structural tubing. They don't see it as being any different than a light pole, although it doesn't have any listings like a light pole.

I've thought of running smurf tube, or some type of flexible conduit through the tubing to make it compliant, but the problem is how to attach or terminate to the conduit that feeds into the base. Also, splices couldn't be made anywhere inside the tubing.

I like the UF idea. You still couldn't make any splices that aren't inside an electrical enclosure of some type, but otherwise it sounds like it would comply.

 

[Ingenieur]

Contractor is the one asking me to seal it.

I have request that manufacturer send backup for their statement saying that the tubular steel is approved for use as an electrical raceway.

I thought the inspector required it (of the contractor)
I would not get sucked into it
have the contractor find an engineer

 

[Sparky1981]

I am going to leave it on the manufacturer to provide me with the back up they used to say "approved for use as a wireway". Without proof I am not stamping anything.

UF cable should work. Thats a great idea. I told the contractor to run by the inspector. The steel manufacturer did create boxes so any splices would be made in a junction box, so I am fairly certain UF cable should be fine.

Thanks!

 

[GoldDigger]

I am sure that structural tubing is not considered a Chapter 3 wiring method or even part of one. But when you have a Chapter 3 wiring method that can either be exposed or protected from damage the sheath would not have to be listed, approved, or even recognized. As long as the inspector sees it as valid protection.

Sent from my XT1585 using Tapatalk

 

[gadfly56]

I am a bit uncertain of how the NEC would treat this. A UL listing as an electrical raceway would close the deal, but I doubt that this framing system has been listed for that purpose. Here is where I am confused:

• 300.3(A) tells me that you can't run single conductors unless you are using a wiring method that is recognized in Chapter 3. I don't see anything in Chapter 3 that would match the description you have given us of this framing system.
• On the other hand, 300.4(B)(1) seems to allow certain types of cables to be run through factory-punched holes in metal framing members. Since that paragraph is part of Chapter 3, does that mean that Chapter 3 has recognized metal frames as an allowable wiring method?

The manufacturer's description of how well they smooth out the holes so that there are no burrs or damaging edges would not be enough to satisfy the requirements of 300.4(B)(1). They need to add listed bushings or grommets at every joint, and I don't think that is happening.

Unistrut is structural and it's listed as raceway.

 

[petersonra]

Unistrut is structural and it's listed as raceway.

only some of it is.

 

[gadfly56]

only some of it is.

That may be so, but if there was a need expressed by the market I'm sure more of it would be. The point is, just because the primary purpose is structural doesn't mean it automatically can't be a listed raceway.