Making connections in Condulet ? Wiring thru machine ?

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milmat1

milmat1

"It Can't Do That !"
Location
Siler City, NC USA
Occupation
Controls Engineer
We have an application of a sensor where we make the connection inside a C-Fitting (form 7 condulet ).

Is making connections inside the C box addressed in the NFPA 70 or 79 ?

What about running wires thru machine body, such as square tubing etc that is part of the machine structure ?
 
314.16(C)(2) addresses spices in conduit bodies.
As far as the machine tubing, 310.10 seems to prohibit single conductors.
 
augie47 said:
314.16(C)(2) addresses spices in conduit bodies.
As far as the machine tubing, 310.10 seems to prohibit single conductors.
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Thanks, 314.16 (70E) seems to cover the c boxes, Thanks.

Not sue how 310-10 covers the machine tubing, maybe I'm missing something..
However in NFPA 79 under 13.5.7 seems to say the use of the machine columns and supports as conduits, is acceptable
 
augie47 said:
314.16(C)(2) addresses spices in conduit bodies.
As far as the machine tubing, 310.10 seems to prohibit single conductors.
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OTOH, does anything inside the machine itself really have to comply with the NEC given it is essentially a piece of utilization equipment?

Personally I am not a fan of running single conductors inside of machine structural elements just because the inside of these kind of elements is not smooth and not really designed as a raceway so might result in damage to the conductor over time. I don't have a major issue with running a cord there though or maybe a raceway of some sort.
 
petersonra said:
OTOH, does anything inside the machine itself really have to comply with the NEC given it is essentially a piece of utilization equipment?

Personally I am not a fan of running single conductors inside of machine structural elements just because the inside of these kind of elements is not smooth and not really designed as a raceway so might result in damage to the conductor over time. I don't have a major issue with running a cord there though or maybe a raceway of some sort.
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Well that is true. And we have a lot of lateral freedom designing the machines control system. We do try to follow 70E and NFPA 79 as close as possible. But honestly we really are governed mostly by product liability laws more than anything else..
I agree the machine structure is not well suited for this, as there can be many sharp edges that are invisible to the installer..

This is a point of constant argument here as to what standards we Have to follow. the answer of course being none. However we wouldn't be in business long if we didn't follow some standards..
Just as we do not have to build UL panels, unless the customer demands such...
 
Industrial machinery (and facilities for that matter) are pretty much exempt from building codes in NC.

From NC General Statute § 143-139

(b9) Nothing in this Article shall extend to or be construed as being applicable to the regulation of thedesign, construction, location, installation, or operation of industrial machinery. However, if during thebuilding code inspection process, an electrical inspector has any concerns about the electrical safety of apiece of industrial machinery, the electrical inspector may refer that concern to the Occupational Safetyand Health Division in the North Carolina Department of Labor but shall not withhold the certificate ofoccupancy nor mandate third-party testing of the industrial machinery based solely on this concern. Forthe purposes of this paragraph, "industrial machinery" means equipment and machinery used in asystem of operations for the explicit purpose of producing a product. The term does not includeequipment that is permanently attached to or a component part of a building and related to generalbuilding services such as ventilation, heating and cooling, plumbing, fire suppression or prevention, andgeneral electrical transmission.
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Roger
 
So many threads in this Forum address "structure" wiring, I addressed my response along those lines.
IMO, if one were installing wiring following the NEC, 310.10 would prohibit single conductors in machine tubing as the tubing is not a listed raceway (a Chapter 3 wiring method).
NFPA79 addresses the machine wiring itslef and I do not work with that Code and can offer no input.
The State of TN where I am employed requires NRTL listing on equipment so I am never called upon to address that,
 
milmat1 said:
Well that is true. And we have a lot of lateral freedom designing the machines control system. We do try to follow 70E and NFPA 79 as close as possible. But honestly we really are governed mostly by product liability laws more than anything else..
I agree the machine structure is not well suited for this, as there can be many sharp edges that are invisible to the installer..

This is a point of constant argument here as to what standards we Have to follow. the answer of course being none. However we wouldn't be in business long if we didn't follow some standards..
Just as we do not have to build UL panels, unless the customer demands such...
Click to expand...

I think you are foolish if you do not design and build control panels to UL 508a standards. There is no extra cost and it is for the most part a bare minimum standard like the NEC and is a whole lot easier to defend in court than just doing any old thing you feel like. But the real reason to do it is so you have some design guide. Otherwise what guides your choices? Now whether you put a UL sticker on it or not is a cost driven decision. But it is not especially expensive to do so. Mostly there are some labeling issues associated with UL508a that add a little cost and the sticker itself is not free.
 
augie47 said:
So many threads in this Forum address "structure" wiring, I addressed my response along those lines.
IMO, if one were installing wiring following the NEC, 310.10 would prohibit single conductors in machine tubing as the tubing is not a listed raceway (a Chapter 3 wiring method).
NFPA79 addresses the machine wiring itslef and I do not work with that Code and can offer no input.
The State of TN where I am employed requires NRTL listing on equipment so I am never called upon to address that,
Click to expand...

exactly where are you going to get an NRTL listing for most one off industrial machines?
 
petersonra said:
I think you are foolish if you do not design and build control panels to UL 508a standards. There is no extra cost and it is for the most part a bare minimum standard like the NEC and is a whole lot easier to defend in court than just doing any old thing you feel like. But the real reason to do it is so you have some design guide. Otherwise what guides your choices? Now whether you put a UL sticker on it or not is a cost driven decision. But it is not especially expensive to do so. Mostly there are some labeling issues associated with UL508a that add a little cost and the sticker itself is not free.
Click to expand...

I guess my best response is we just have no need to do so.
And we build custom designed machinery one at a time..
 
This shop was a mess when I came here, I have tried to get us settled on some type of standard. If I can get the shop in compliance with NFPA 79, then maybe move forward to becoming a UL shop...
But like many small companies it is frustrating when the owner gets involved and says do this or do that. Even if it is wrong..
 
Besoeker said:
Sorry, Conduit body like a junction box as opposed to the black tube itself?
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A little off topic, but I've never seen black electrical conduit. I've done no research, but I'd guess that 99% is galvanized, the remaining 1% is divided among stainless, aluminum, and other. I believe it is made in brass and copper but have not personally seen it. Recognize I'm not an electrician, rather a (now retired) electrohydraulic guy whose involvement is in design, specification and commissioning.

We use black pipe for FLUID conduits. Galvanized is "bad" because the internal galvanizing tends to come loose and plug orifices and interfere in other portions of operations.
 
petersonra said:
they can come out and evaluate the control panel but unless there is a UL standard for the machine itself there is no way to list the machine.
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I don't ask questions.. I just look for the label :) "trained monkey"
 
petersonra said:
they can come out and evaluate the control panel but unless there is a UL standard for the machine itself there is no way to list the machine.
Click to expand...

I dealt with this all the time as an OEM.
We get a spec saying our equipment must be UL listed. We take exception and tell them there is no standard so not possible. There is a CSA standard and our equipment is CSA listed and labeled.
This was always accepted except by some in LA and NYC.
 
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