Do you have to secure MC cable in a metal wireway?

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wmabantajr

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Do you have to secure MC cable in a metal wireway per 330.30(B)? I've read article 376, Metal Wireways, and it doesn't define how to secure electrical wires and cables inside the wireway. Does that mean you don't have to? I have a 10" wide X 10" deep x 9' high vertical metal wireway with ten-twelve 12/2 MC cables running from device boxes toward the bottom of the unit through the top of the unit. I'm looking for documentations that permits me from not having to secure the MC cable in a metal wireway.
 
wmabantajr said:
Do you have to secure MC cable in a metal wireway per 330.30(B)? I've read article 376, Metal Wireways, and it doesn't define how to secure electrical wires and cables inside the wireway. Does that mean you don't have to? I have a 10" wide X 10" deep x 9' high vertical metal wireway with ten-twelve 12/2 MC cables running from device boxes toward the bottom of the unit through the top of the unit. I'm looking for documentations that permits me from not having to secure the MC cable in a metal wireway.
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300.19 But it may not be what you're looking for.
 
I have a 10" wide X 10" deep x 9' high vertical metal wireway with ten-twelve 12/2 MC cables running from device boxes toward the bottom of the unit through the top of the unit.
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What's "the unit",the wireway? Cables come out of device boxes at the bottom. Where do the cables go at the top? This sounds like a chase to me.

-Hal
 
wmabantajr said:
Do you have to secure MC cable in a metal wireway per 330.30(B)? I've read article 376, Metal Wireways, and it doesn't define how to secure electrical wires and cables inside the wireway. Does that mean you don't have to? I have a 10" wide X 10" deep x 9' high vertical metal wireway with ten-twelve 12/2 MC cables running from device boxes toward the bottom of the unit through the top of the unit. I'm looking for documentations that permits me from not having to secure the MC cable in a metal wireway.
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It would be my opinion (others will most certainly disagree) that the Type MC shall be secured and supported in accordance with 330.30. I know that the jurisdictions I have been associated with would have permitted a horizontal wireway where Type MC Cables may pass trough as being considered secure and supported as in 330.30(C). Where in doubt the Type MC Cable has to meet the securing and supporting components of 330.30(B). I would also assume that the Type MC Cable is being secured (in some 330.40 fashion) to the wireway as it enters,but in a way that continues on without breaching the armor which again inside the wireway I would consider it secure and supported. Again assuming that is what you are describing.

Assuming you meet the fitting requirements of 330.40 (listed and identified) then once inside the wireway, assuming again you meet the other code rules of the wireway itself, they I would consider the Type MC Cable secured and supported. I also do not believe anything with regards to 300.19 applies here.

Just my thoughts on the subject.
 
I don't see how the MC is "secured" unless you do something to "secure" it.

I think it is another one of those provisions that the actual wording of the code is sometimes not adhered to in the interest of common sense.

Besides, the code does not define what the term secured means. That kind of leaves it up to interpretation.

The code is also unclear about just what the MC has to be secured to. If you tie wrap a couple of MC cables together they are secured to each other. Whether that does any good or not is another issue.
 
ok

But

(A) Spacing Intervals — Maximum. Conductors in vertical
raceways shall be supported if the vertical rise exceeds
the values in Table 300.19(A). One cable support shall be
provided at the top of the vertical raceway or as close to the
top as practical. Intermediate supports shall be provided as
necessary to limit supported conductor lengths to not
greater than those values specified in Table 300.19(A).

Exception: Steel wire armor cable shall be supported at
the top of the riser with a cable support that clamps the
steel wire armor. A safety device shall be permitted at the
lower end of the riser to hold the cable in the event there is
slippage of the cable in the wire-armored cable support.
Additional wedge-type supports shall be permitted to relieve
the strain on the equipment terminals caused by expansion
of the cable under load.
 
dkidd said:
ok

But

(A) Spacing Intervals — Maximum. Conductors in vertical
raceways shall be supported if the vertical rise exceeds
the values in Table 300.19(A). One cable support shall be
provided at the top of the vertical raceway or as close to the
top as practical. Intermediate supports shall be provided as
necessary to limit supported conductor lengths to not
greater than those values specified in Table 300.19(A).

Exception: Steel wire armor cable shall be supported at
the top of the riser with a cable support that clamps the
steel wire armor. A safety device shall be permitted at the
lower end of the riser to hold the cable in the event there is
slippage of the cable in the wire-armored cable support.
Additional wedge-type supports shall be permitted to relieve
the strain on the equipment terminals caused by expansion
of the cable under load.
Click to expand...

You are blowing that section way out of it's intended context. The use of the term cable within that section has nothing to do with Type MC Cable.
 
petersonra said:
I don't see how the MC is "secured" unless you do something to "secure" it.

I think it is another one of those provisions that the actual wording of the code is sometimes not adhered to in the interest of common sense.

Besides, the code does not define what the term secured means. That kind of leaves it up to interpretation.

The code is also unclear about just what the MC has to be secured to. If you tie wrap a couple of MC cables together they are secured to each other. Whether that does any good or not is another issue.
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Horizontal runs of Type MC cable installed in wooden or metal framing members or similar supporting means shall be considered supported and secured where such support does not exceed 1.8-m (6-ft) intervals.

Heck since you are are REACHING anyway....I will reach....As a maker of such a cable, we are fine with this interpretation. As for your jurisdiction, argue at will.

I agree to a point...however, tying a few MC Cables together and supporting themselves would invoke a violation of Section 300.11(C)..;)
 
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Interesting enough....that section 300.19, which is titled "300.19 Supporting Conductors in Vertical Raceways." kinda seals it FATE....since Type MC Cable is not a "Raceway" it really does not apply here. Now, the "steel" cable you see referenced in that section is more of an individual "cabled" conductor with a wire support and is named "Steel wire armor cable" and not the same as Type MC Cable (or AC for that matter).

I will admit, I think I am going to submit something in 2020 on this but alas.....it is what it is.

This might help explain it...https://en.wikipedia.org/wiki/Steel_wire_armoured_cable
 
wmabantajr said:
Do you have to secure MC cable in a metal wireway per 330.30(B)? I've read article 376, Metal Wireways, and it doesn't define how to secure electrical wires and cables inside the wireway. Does that mean you don't have to? I have a 10" wide X 10" deep x 9' high vertical metal wireway with ten-twelve 12/2 MC cables running from device boxes toward the bottom of the unit through the top of the unit. I'm looking for documentations that permits me from not having to secure the MC cable in a metal wireway.
Click to expand...
Can you provide a photo of this? Sepcifically a photo of the "unit". What is the "unit"? And where are these device boxes mounted? And a photo of how the MC enters the raceway. I see that the NEC allows MC to be installed in a raceway but I have never seen this. I imagine the supporting requirements are the same 330.30(D)(1) Would allow you to not support it if its impractical. The UL Whitebook does not provide any guidance either.
Cheers
 
MasterTheNEC said:
You are blowing that section way out of it's intended context. The use of the term cable within that section has nothing to do with Type MC Cable.
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Exception: Steel wire armor cable...
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Is MC cable not steel wire armored?

330.2 Definition.
Metal Clad Cable, Type MC. A factory assembly of one
or more insulated circuit conductors with or without optical
fiber members enclosed in an armor of interlocking metal
tape, or a smooth or corrugated metallic sheath.
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I suppose by definition MC could have an armor of something other than steel (I think AL is available) and then it would not need the required vertical support, which is a strange result of reading what the code actually says. or the MC might be deemed to have a metallic sheath rather than metallic armor, in which case it would be exempt from the vertical support requirements.

I wonder what the difference between armor and sheath is? there are several places I found in the code that refers to "sheath or armor" which suggests they are not the same thing.

ETA: Interestingly, type AC cable is described as having armor, with no provision for sheath.

320.2 Definition.
Armored Cable, Type AC. A fabricated assembly of insulated
conductors in a flexible interlocked metallic armor.
Click to expand...
 
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View the wiki link....and as a maker of Type MC...NO it is not the same. However, believe as you wish my friend as I fret not.;)

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MasterTheNEC said:
View the wiki link....and as a maker of Type MC...NO it is not the same. However, believe as you wish my friend as I fret not.;)

Sent from my SAMSUNG-SM-G935A using Tapatalk
Click to expand...

I think you are probably correct that the code section cited is referring to type SWA cable and not a generic term for cable armored with steel, but it is curious it does not actually say so.

oddly this is the only place in the code the term "steel wire armor cable" appears according to a PDF search. by normal grammatical construction rules, that would generally make it a generic term and not something specific.
 
Ok...so I was leaving the GYM and it was a moment of Roid Rage. To be more specific, there is a specific industry product called "Steel Wire Armored Cable" and it has a supportive structure that is integral to its construction. It is also in many cases pulled in raceways where it's integral support is supported in the raceway, at the ends with a special fitting.

Type MC Cable is except (if I can use that term) based on the rules within 330.30 and 300.19 is specific in nature. The exception is to the use of that special type of cable....

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petersonra said:
I think you are probably correct that the code section cited is referring to type SWA cable and not a generic term for cable armored with steel, but it is curious it does not actually say so.

oddly this is the only place in the code the term "steel wire armor cable" appears according to a PDF search. by normal grammatical construction rules, that would generally make it a generic term and not something specific.
Click to expand...
We on the code panels await your proposal fella

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petersonra said:
Is MC cable not steel wire armored?



I suppose by definition MC could have an armor of something other than steel (I think AL is available) and then it would not need the required vertical support, which is a strange result of reading what the code actually says. or the MC might be deemed to have a metallic sheath rather than metallic armor, in which case it would be exempt from the vertical support requirements.

I wonder what the difference between armor and sheath is? there are several places I found in the code that refers to "sheath or armor" which suggests they are not the same thing.

ETA: Interestingly, type AC cable is described as having armor, with no provision for sheath.
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From 2005 ROP in part

Substantiation:
Steel wire armor cable as referenced in this exception remains elusive. I can find no further reference to this wiring method in the NEC or in any of the NRTL product directories. The exception first appeared in the 1975 edition of the NEC, but I have no access to any documentation. Since this product is not code recognized, there appears to be no reason to make any NEC reference to it.
Panel Meeting Action: Reject
Panel Statement:
The text in the 1974 NEC Preprint to the 1975 NEC appears to provide documentation that the exception was inserted to permit steel AC cable to be supported at the top of the riser. Throughout the text of the supporting comment for permitting this steel cable, the submitter continuously refers to the AC cable as wire armored cable and steel wire armored cable. He also states that this type of cable had been in use for 50 or more years in these applications without a single case of failure of a support for these cables.
 
MasterTheNEC said:
We on the code panels await your proposal fella

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Click to expand...

Use your considerable clout to fix the NFPA's crappy website, publish ROPs and ROCs in a readable format again, and you might find as many proposals to read as previous cycles - might even be some good ones out there.
 
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