What Type of Cable is This

[iceworm]

Well you must have better eyes than most of us to be able to see that the cable is different that what I linked to.

No better than 20-25 and I have to have cheaters for anything under 5 feet.
But I do have a lot of years specing, buying, looking, pulling, reviewing ... (looking for more verbs)

 

[kwired]

I agree with citing this as an issue. External damage doesn't have to come from human activity. An animal can chew on the PVC covering, compromising its watertightness. Even a loose rock rolling down the steep hill can damage the cable.

With any wiring method chosen external damage is a consideration. Even if this were run in RMC, there is still some things that can damage it, but it becomes a question of how likely may that be and where to draw the line of what is reasonably acceptable for the situation.

 

[iceworm]

There is a minor issue with large feeders, paralleled cables.

3/C - MC-HL will have 3 grounding conductors in the innerstices. For example"

3-250 has 3-#8 grounding conductors = GC equivalent 49 kcmil
3-350 has 3-#7
3-500 has 3-#6 = GC equivalent 79 kcil​

The GC are sized for the usual sized CB for a single cable, but is too small if the cables are paralleled.
Art 250.118.10 says one can use the combined metalic sheath and grounding conductors, which gets one up into the 4 paralleled range.

So paralleled instllations are ok, one should do the calculation for the sheath to get an equivalent GC size to verify

 

[iceworm]

... This cable is run underground for part of the way down the hill, and sits on top of the dirt and rocks the rest of the way down. ....

Missed this. That is a code issue.

Buried is fine. Laying on top of the dirt is not. Odd but true. Yep, had the AHJ call me on it - either buried per 300.5 or secured per 330.30

330.30.B and C Supported and secured in intervals not to exceed 6 feet.

Solution:
Treated wood 4 x 4 sleepers at six foot intervals, wiggled down into the fill a bit. Cable fastened to sleepers with two-hole clamps. Worked great. AHJ happy.

Better? or Safer? than laying on the ground. Don't know. Se the part about AHJ happy.

 

[rbalex]

You're saying you were in the development if MC-HL?

If that is what you are saying - bless you.

So, tell us a story.

Considering I have 30 years in fighting conduit, followed by 20 years of MC-HL, I ready to shake hands and buy you a beer. I'd even share my good Scotch.

worm

If you go to the history of what became MC-HL [NEC 1996] it was proposed by the API Subcommittee on Electrical Equipment (SOEE). I was the instigator within the SOEE.

501-4. WiringMethods. Wiring methods shall comply with (a)
and (b) below.
(a)Class I, Division 1. In Class I, Division 1 locations,
threaded rigid metal conduit, threaded steel intermediate metal
conduit, or Type MI cable with termination fittings approved for
the location shall be the wiring method employed. All boxes, fittings,
and joints shall be threaded for connection to conduit or
cable terminations and shall be explosionproof. Threaded joints
shall be made up with at least five threads fully engaged. Type MI
cable shall be installed and supported in a manner to avoid tensile
stress at the termination fittings.
Exception No. 1: Rigid nonmetallic conduit complying with Article
347 shall be permitted where encased in a concrete envelope a
minimum of 2 in. (50.8 mm) thick and buried below the surface
under not less than 2 ft (610 mm) of earth. Where rigid nonmetallic
conduit is used, threaded rigid metal conduit or threaded steel
intermediate metal conduit shall be used for the last 2 ft (610 mm)
of the underground run to emergence or to the point of connection
to the aboveground raceway. An equipment grounding conductor
shall be included to provide for electrical continuity of the raceway
system and for grounding of noncurrent-carrying metal parts.
Exception No. 2: In industrial establishments with restricted public
access, where the conditions of maintenance and supervision
ensure that only qualified persons will service the installation, Type
MC cable, listed for use in Class I, Division 1 locations, with a gas/
vaportight continuous corrugated aluminum sheath, an overall
jacketof suitable polymeric material, separate grounding conductors
in accordance with Section 250-95, and provided with termination
fittings listed for the application shall be permitted.

I was also a major commentor on the original UL MC-HL standard.

 

[kwired]

Missed this. That is a code issue.

Buried is fine. Laying on top of the dirt is not. Odd but true. Yep, had the AHJ call me on it - either buried per 300.5 or secured per 330.30

330.30.B and C Supported and secured in intervals not to exceed 6 feet.

Solution:
Treated wood 4 x 4 sleepers at six foot intervals, wiggled down into the fill a bit. Cable fastened to sleepers with two-hole clamps. Worked great. AHJ happy.

Better? or Safer? than laying on the ground. Don't know. Se the part about AHJ happy.

That is all you gained there, AHJ being happy that they got to assert their authority.

 

[iceworm]

.... I was the instigator within the SOEE.


I was also a major commentor on the original UL MC-HL standard.

Alright. Good job. Thank you.
I going to start a fund for a monument. There is a park right at the Arctic Circle - Perfect spot

 

[rbalex]

Alright. Good job. Thank you.
I going to start a fund for a monument. There is a park right at the Arctic Circle - Perfect spot

Is it on the Dalton Highway? If so, it's not too far from my hometown (Fairbanks).

 

[iceworm]

Is it on the Dalton Highway? If so, it's not too far from my hometown (Fairbanks).

Yes. Between Pump 5 and Pump 6, milepost 115, North of the Yukon. So pretty close, ~170 miles from Fairbanks

Nope, I'm not in the picture