conduits to cable tray

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stickelec said:
That is a very well prepared document and something that would be of real benefit in a Engineering Spec. But... I honestly cannot find were it is required to use a Sealing Bushing on conduit that is attached to a Cable Tray.

As mentioned by Tori, we are not talking about enclosures. The best I can dig out of the 2005 NEC Art 300 and 392 is that an Insulated Bushing is all that is required.

I'm not trying to be argumentive, just trying to learn if I have been wrong all these years. Please point to the exact ref in the NEC that shows the requirement. Thanks
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The conduit is to be installed as a complete system. It is a closed system all openings should be closed. Would you leave an opening on a condulet open? A conduit is nothing more than an extention of an enclosure in its functionality. It contains insulated conductive parts that may contain connections in specified parts of the system and only differs from an enclosure that in enclosures you have switching devices.
Would you protect a Romex emerging from a box with just an insulated bushing?

All the specific an relevant parts of the Code are cited. I have developed this a while ago, had a detailed presentation and won my case. The Code is not specific and clear on this issue, but there is sufficient precedence in other areas of the intent a direction of the Code.
 
I'm not exposing the Type-TC to anything it is not already exposed to in the Tray...actually less, no sunlight or potential physical damage.

I believe if the Sealing Bushing is required by the AHJ then it is fine, but it should not be stated that the NEC requires it. IMO
 
stickelec said:
I'm not exposing the Type-TC to anything it is not already exposed to in the Tray...actually less, no sunlight or potential physical damage.

I believe if the Sealing Bushing is required by the AHJ then it is fine, but it should not be stated that the NEC requires it. IMO
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You are missing the point, it is not harm to the TC cable that is the issue here.
The issue is:
- securing the cable at the point of entry,
(functionaly it serves as a stress relief of the conductor terminations, the same reason why you are securing a Romex at the box entry point.)
- closing an opening into an electrical system.
(Functionally it serves as follows. A GRSC provides a NEMA 3 degree protection as minimum. When you only use a pop-on bushing the opening is so large taht it does not meet ANY NEMA rating. You are obliged to maintain the equipment rating with your method of installation. I have seen many open ended conduit connecting to motor junction boxes where the JB had filled up with rainwater BECAUSE of the open conduit end. I have seen MCC's filled up with dust and eventually shorting buses because the dust accumulation via the short conduit extentions with bushings that facilitated the cable entry AND acted as dust collectors, nullifying the NEMA1 gasketed rating of the MCC.)
 
This is like playing Ping Pong. :grin:

I assume you are making reference to 300.18 in regard to a "complete system". But it specifically does not mention or indicate Tray.

Let me throw out a scenario: I have a Tray 12 ft above grade. I have another Tray 10ft above grade, but 25 ft from, the upper Tray.

Now...from the upper Tray I run a 2" RGC down the support-leg, go underground, and up to the lower Tray.

Do you think I still need Sealed Bushings, and if so is your opinion supported by 300.18?
 
stickelec said:
This is like playing Ping Pong. :grin:

I assume you are making reference to 300.18 in regard to a "complete system". But it specifically does not mention or indicate Tray.

Let me throw out a scenario: I have a Tray 12 ft above grade. I have another Tray 10ft above grade, but 25 ft from, the upper Tray.

Now...from the upper Tray I run a 2" RGC down the support-leg, go underground, and up to the lower Tray.

Do you think I still need Sealed Bushings, and if so is your opinion supported by 300.18?
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It is not 300.18 it is 344.42 among others.

You are chaning the scenario. Read tyhe original posting, as my reply is germaine to that question and issue.
As to answer your question: absolutely not, and for the same two reasons why you need to do in the other cases;

1./ In this case you are not using the conduit as a raceway, but as a support system. You could have used any other kind of support system from/to ground and direct buried the TC cable.

2./ You do not need a stress relief since you are not terminating the conductors.
 
Tori said:
this picture is a cable connector for individual tray conductors (multi cable) for termination to a jbox or cabinate from tray

I was under the impression, perhaps wrongly, that you were talking about a pipe that comes from a panel then terminates to tray allowing conductors to go on their merry way on the tray system till they get picked up by another pipe that starts at the tray and termiantes at a dissconnect or a control cabinate in a non hazardous atmosphere
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As Laszlo has mentioned, it really has nothing to do with the cable tray. Regarding this discussion topic, I see only three methods of bringing a TC-type cable into a NEMA-rated enclosure, and maintaining the NEMA rating...

cgbusage.gif

NOTE: Required additional securing of cable and conduit have been omitted for clarity.
 
Smart $ said:
As Laszlo has mentioned, it really has nothing to do with the cable tray. Regarding this discussion topic, I see only three methods of bringing a TC-type cable into a NEMA-rated enclosure, and maintaining the NEMA rating...

cgbusage.gif

NOTE: Required additional securing of cable and conduit have been omitted for clarity.
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And BINGO was it's namo........
 
NEMA 4 by definition: "Enclosures are intended for indoor or outdoor use primarily to provide a degree of protection against windblown dust and rain, splashing water, and hose-directed water; undamaged by the formation of ice on the enclosure."

It doesn't sound like the N4 rating is intended to be waterproof...at least in the strictest sense. I believe an open-ended conduit (on a Tray) that has a properly positioned and secured drip-loop may admit a small amount of water in a blowing rain. But if the presence of water is the issue, then I think we could agree that all underground conduit is a problem. Now I bring up a Form-7 Conduit system that originates 100 ft in the air and ends at an enclosure at ground-level. Form-7 fittings leak, therefore how do you maintain the N4 rating on the Enclosure?

My experience has been if a Conduit leaves a Tray going to an Enclosure, it will enter the Enclosure "from the bottom" via a Form-7 Tee and Drain. I believe the Drain maintains the N4 per the definition.
 
stickelec said:
NEMA 4 by definition: "Enclosures are intended for indoor or outdoor use primarily to provide a degree of protection against windblown dust and rain, splashing water, and hose-directed water; undamaged by the formation of ice on the enclosure."

It doesn't sound like the N4 rating is intended to be waterproof...at least in the strictest sense. I believe an open-ended conduit (on a Tray) that has a properly positioned and secured drip-loop may admit a small amount of water in a blowing rain. But if the presence of water is the issue, then I think we could agree that all underground conduit is a problem. Now I bring up a Form-7 Conduit system that originates 100 ft in the air and ends at an enclosure at ground-level. Form-7 fittings leak, therefore how do you maintain the N4 rating on the Enclosure?

My experience has been if a Conduit leaves a Tray going to an Enclosure, it will enter the Enclosure "from the bottom" via a Form-7 Tee and Drain. I believe the Drain maintains the N4 per the definition.
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NEMA 4 IS considered to be waterproof. What you may be thinking of submersible. Form 7 fittings are equipped with neoprene gaskets and suitable for raintight installation.

Potential leaks and condenstation problems in high humidity outdoor installations of large conduit sytems are avoided by installing low point drains and not permitting top entry of enclosures.
 
weressl said:
NEMA 4 IS considered to be waterproof. What you may be thinking of submersible. Form 7 fittings are equipped with neoprene gaskets and suitable for raintight installation.

Potential leaks and condenstation problems in high humidity outdoor installations of large conduit sytems are avoided by installing low point drains and not permitting top entry of enclosures.
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Hoffman does not agree.

http://www.hoffmanonline.com/stream_document.aspx?rRID=16039&pRID=15193
 
stickelec said:
Hoffman does not agree.

http://www.hoffmanonline.com/stream_document.aspx?rRID=16039&pRID=15193
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Hoffman did not write this, NEMA did:

"Enclosures are intended for indoor or outdoor use primarily to provide a degree of protection against windblown dust and rain, splashing water, and hose directed water; undamaged by the formation of ice on the enclosure."

If the above does not mean waterproof to you, then please explain what does? We were talking about indoor or outdoor installations where water may be encountered either by rain or directed hose and the enclosure provides protection against the enrty of such water.

Dictionary:

wa?ter?proof

Pronunciation: (w?'tur-prOOf", wot'ur-), [key]
?adj.
1. impervious to water.
2. rendered impervious to water by some special process, as coating or treating with rubber: a waterproof hat.
​
im?per?vi?ous

Pronunciation: (im-p?r'vē-us), [key]
?adj.
1. not permitting penetration or passage; impenetrable: The coat is impervious to rain.
2. incapable of being injured or impaired: impervious to wear and tear.
3. incapable of being influenced, persuaded, or affected: impervious to reason; impervious to another's suffering. Also,im?per?vi?a?blePronunciation: (im-p?r'vē-u-bul). [key]

​
 
stickelec said:
Hoffman is the Manufacturer... its their box (for example). Did they mis-quote the definition of NEMA-4?
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Would you please explain what are you trying to say?

I have provided the quote on the Hoffman webpage that CITES the NEMA definitions. Hoffman did not write that NEMA did. Then I went on to include the definition what waterproof means and why the NEMA 4 definition is therefore waterproof.

You go ahead and copy what YOU are refering to and what is it what you are trying to say. I am getting a little bit bored with running in circles....:rolleyes:
 
I have worked in many tray settings and have never used a gland on the pipe terminations to the tray -
the pipe does need a tray attachment means (to assure ground coninuity) and a bushing to prevent harm to the wire

the tray conductors whether multi cables or individual current conductors ( differant trays of course) are all secured to the tray along its entirety for the length of the cable

the only referance i see that applies from your link
370-17. Conductors Entering Boxes, Conduit Bodies, or Fittings
Openings to Be Closed. Openings through which conductors enter shall be adequately closed.

I do not think the intent of this phrase is to desribe a connector with a bushing attaching to tray

the code cannot be read by choosing articles from jumping all around you must look at the intent

I see from your contribution you seem to talking about stress relief

I am curious you said you made a presentation and won the case - to whom did you present this ?

also this is not an arguement - I just respectfully disagree
 
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Tori said:
I have worked in many tray settings and have never used a gland on the pipe terminations to the tray...
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Same here... but the fact we have never used a cable gland in these instances does not automatically equate such with code compliance!

the tray conductors whether multi cables or individual current conductors ( differant trays of course) are all secured to the tray along its entirety for the length of the cable
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Securing and/or supporting the contents of cable tray is part of its purpose and has nothing to do with terminating a conduit raceway.
392.2 Definition.

Cable Tray System. A unit or assembly of units or sections and associated fittings forming a structural system used to securely fasten or support cables and raceways.
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the only referance i see that applies from your link
370-17. Conductors Entering Boxes, Conduit Bodies, or Fittings
Openings to Be Closed. Openings through which conductors enter shall be adequately closed.
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What about...
300.15 Boxes, Conduit Bodies, or Fittings — Where Required.

A box shall be installed at each outlet and switch point for concealed knob-and-tube wiring.

Fittings and connectors shall be used only with the specific wiring methods for which they are designed and listed.

Where the wiring method is conduit, tubing, Type AC cable, Type MC cable, Type MI cable, nonmetallic-sheathed cable, or other cables, a box or conduit body shall be installed at each conductor splice point, outlet point, switch point, junction point, termination point, or pull point, unless otherwise permitted in 300.15(A) through (M).

...

(C) Protection. A box or conduit body shall not be required where cables enter or exit from conduit or tubing that is used to provide cable support or protection against physical damage. A fitting shall be provided on the end(s) of the conduit or tubing to protect the cable from abrasion.

...

(F) Fitting. A fitting identified for the use shall be permitted in lieu of a box or conduit body where conductors are not spliced or terminated within the fitting. The fitting shall be accessible after installation.
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Note the green text refers to conduit as used in the middle instance of the diagram I posted earlier.
 
Smart $ said:
Same here... but the fact we have never used a cable gland in these instances does not automatically equate such with code compliance!


Securing and/or supporting the contents of cable tray is part of its purpose and has nothing to do with terminating a conduit raceway.
​


What about...
​
Note the green text refers to conduit as used in the middle instance of the diagram I posted earlier.
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what in this post designates the need for a pipe gland ???-if there even is such a fitting or call for one which I don't think there is
 
Tori said:
what in this post designates the need for a pipe gland ???-if there even is such a fitting or call for one which I don't think there is
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It's not so much that 300.15 calls for a cable gland, but rather that it does call for a box or conduit body at the transition (i.e. junction, termination, pull point). When a box or conduit body is used, you'd be required to use a fitting to bring the cable into the box or conduit body. 300.15(F) simply permits you to use a fitting to enter the [conduit] raceway directly, without the box or conduit body.
 
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I'm going to buy-in that the conduit needs to be closed based specifically on 314.15 (A) and 314.17 (A)

Exact and to the point code references certainly streamline things and make discussions more beneficial.

I work over the entire State of Texas (Industrial) and I would venture to say this is probably one of the most overlooked requirements in construction.

Cheers...
 
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