Ditch Depth

[augie47]

Another inspector asked if there was a minimum cover for a conduit containing the control cable for a LED sign display.
In this case it is unknown if it is a Class 2 or Class 3 (or other) circuit, but in looking for an answer we don't find cover requirements for Class2, 3 or communications circuits.(Looking in Art 725 & 800)
Any input is appreciated,

 

[Dennis Alwon]

Gus does T.300.5 Column 5 not cover it?

 

[augie47]

Gus does T.300.5 Column 5 not cover it?

I was leaning that way until I read 725.3

 

[kwired]

Gus does T.300.5 Column 5 not cover it?

Maybe it should, but the heading of the column is fairly specific to what it does cover and this application is not included in that wording, it just mentions irrigation controls and landscape lighting.

 

[Dennis Alwon]

Maybe it should, but the heading of the column is fairly specific to what it does cover and this application is not included in that wording, it just mentions irrigation controls and landscape lighting.

So a sign is out in the yard-- is that a landscape light? Just joking but IMO, the use of T300.5 is what I would use. Why would it be okay for a sign but not landscape lighting? Doesn't make sense

 

[kwired]

So a sign is out in the yard-- is that a landscape light? Just joking but IMO, the use of T300.5 is what I would use. Why would it be okay for a sign but not landscape lighting? Doesn't make sense

I agree, but at same time is not what it says. How many times have we had seemingly endless conversation over interpretation of what something in the NEC actually says? If it is intended to cover the OP application then it needs reworded to make that more clear, it certainly wouldn't be that hard to make it a little more non specific, but what is mentioned in the heading of that column is fairly specific in nature.

 

[Dennis Alwon]

I agree, but at same time is not what it says. How many times have we had seemingly endless conversation over interpretation of what something in the NEC actually says? If it is intended to cover the OP application then it needs reworded to make that more clear, it certainly wouldn't be that hard to make it a little more non specific, but what is mentioned in the heading of that column is fairly specific in nature.

I understand what it says but one could argue that the sign is part of the landscape.

 

[kwired]

I understand what it says but one could argue that the sign is part of the landscape.

You can argue about anything you so desire to

Some installations the sign is the main structure - does that still make it part of the landscape? Think isolated advertising signs along roadways.

 

[renosteinke]

Well, if you don't like the wording of the actual codes - feel free to make your own up!

Personally, I hate digging. I don't ever want to dig a trench more than once. So, you have to ask two questions: What's the worst that can happen, and How easy is it to harm the cable?

My first "trench level" is the depth of a full shovel blade. This will protect against the casual shovel bite from, say, the gardener working on the sprinkler pipes.

The smaller the cable, the more likely I am to use pipe. I'd much rather be able to pull in a replacement later, than dig again - and small cables are more easily damaged. Hate it when a rock in the backfill cuts the new cable!

Still, a cut control cable probably won't even be noticed when the shovel strikes. That same shovel hitting, say, a PoCo feeder will be a somewhat more dramatic event. Things get that bad, I want the cables in pipe, encased in cement, and below the level of the first backhoe pass.

So, forget about the code. Use your head instead; good design always meets code. Simply meeting code usually results in introducing other problems.

 

[petersonra]

Another inspector asked if there was a minimum cover for a conduit containing the control cable for a LED sign display.
In this case it is unknown if it is a Class 2 or Class 3 (or other) circuit, but in looking for an answer we don't find cover requirements for Class2, 3 or communications circuits.(Looking in Art 725 & 800)
Any input is appreciated,

my personal opinion is that no cover at all is required because it is not referenced in article 725.

however, I think you still have to protect the cabling from damage.

 

[resistance]

T300.5 does not cover class 2 and 3 cable. No requirement, unless your jurisdiction says different.
I?m with petersonra.

 

[Dennis Alwon]

however, I think you still have to protect the cabling from damage.

And what exactly would that entail. My point is using Col.5 seems to be the way to go to cover yourself. Yes I know it isn't exactly what we are looking at but not a bad guideline. As an inspector you may not be able to enforce it but as a contractor I would do it that way

 

[petersonra]

And what exactly would that entail. My point is using Col.5 seems to be the way to go to cover yourself. Yes I know it isn't exactly what we are looking at but not a bad guideline. As an inspector you may not be able to enforce it but as a contractor I would do it that way

don't know. all I can say with any certainty is that the cover table does not appear to apply to class 2 or 3 cables.

with other cables that are covered by this table, you have what amounts to a prima facie case that the cover requirements provide adequate protection.

 

[mwm1752]

The sign may not be intended for illuminating the landscape but IMO landscape lighting could also be interpreted as a luminaire placed upon a landscape. The sign by definition is a luminaire.

 

[cadpoint]

725, License to do anything, JMO, I hate it , I seen it way abused and not adhered to, all the time.

90.3
Chapter 1-4 Applies generally to all electrical installations.
Chapter 5-7 Supplements or modifies Chapter 1-4.

Their is no wholesale waiver of 1-4 wire methods in 725, it is based on Chapter 1-4
electrical installations (see above) it ?Supplements or modifies Chapter1-4?.
When called out, if it's not called out then it defaults to 1-4! That the way I was taught!
Chapter 8 gets the wholesale don't follow 1-7.

Tell me now, correct me of my mislead thoughts; I've been meaning to talk to my old teacher and tell
them also of my Code Love! Let me convey to him that I was mis-taught.

I'm with Dennis 300.5 is in! Don't get stuck on the Table readthe Article.
_________________________________________________________________________________________
What bothers me is that this Class thing; is this only Roman numerals whenin classified area
andonly numerical numbers when not in Hazardous area/conditions?
Are we not talking about the same thing at all.

What is the the difference between 1,2,3 and I, II, III. With Class 1,2...this is in reference to these types of building structures. This type of Class(s) and there is not (is no mention of this)any mention in our 70 Code; it's a building code, reference. FYI Class only is in index in respects to Hazardous I,II, etc.
Schoolme please, I'm so Bored!!!!

Hmm, I'll bet 8 out of 10 electricians would fail Building Classification 1,2, and understanding their subdivisions.

More Fuel for the Mike Holt Submitting Machine!

 

[resistance]

725, License to do anything, JMO, I hate it , I seen it way abused and not adhered to, all the time.

90.3
Chapter 1-4 Applies generally to all electrical installations.
Chapter 5-7 Supplements or modifies Chapter 1-4.

Their is no wholesale waiver of 1-4 wire methods in 725, it is based on Chapter 1-4
electrical installations (see above) it ?Supplements or modifies Chapter1-4?.
When called out, if it's not called out then it defaults to 1-4! That the way I was taught!
Chapter 8 gets the wholesale don't follow 1-7.

Tell me now, correct me of my mislead thoughts; I've been meaning to talk to my old teacher and tell
them also of my Code Love! Let me convey to him that I was mis-taught.

I'm with Dennis 300.5 is in! Don't get stuck on the Table readthe Article.
_________________________________________________________________________________________
What bothers me is that this Class thing; is this only Roman numerals whenin classified area
andonly numerical numbers when not in Hazardous area/conditions?
Are we not talking about the same thing at all.

What is the the difference between 1,2,3 and I, II, III. With Class 1,2...this is in reference to these types of building structures. This type of Class(s) and there is not (is no mention of this)any mention in our 70 Code; it's a building code, reference. FYI Class only is in index in respects to Hazardous I,II, etc.
Schoolme please, I'm so Bored!!!!

Hmm, I'll bet 8 out of 10 electricians would fail Building Classification 1,2, and understanding their subdivisions.

More Fuel for the Mike Holt Submitting Machine!

Mike Holt disagrees with you and Dennis?as his literature says it doesn?t apply.

 

[petersonra]

take a look at 725.3

 

[kwired]

725, License to do anything, JMO, I hate it , I seen it way abused and not adhered to, all the time.

90.3
Chapter 1-4 Applies generally to all electrical installations.
Chapter 5-7 Supplements or modifies Chapter 1-4.

Their is no wholesale waiver of 1-4 wire methods in 725, it is based on Chapter 1-4
electrical installations (see above) it ?Supplements or modifies Chapter1-4?.
When called out, if it's not called out then it defaults to 1-4! That the way I was taught!
Chapter 8 gets the wholesale don't follow 1-7.

Tell me now, correct me of my mislead thoughts; I've been meaning to talk to my old teacher and tell
them also of my Code Love! Let me convey to him that I was mis-taught.

I'm with Dennis 300.5 is in! Don't get stuck on the Table readthe Article.
_________________________________________________________________________________________
What bothers me is that this Class thing; is this only Roman numerals whenin classified area
andonly numerical numbers when not in Hazardous area/conditions?
Are we not talking about the same thing at all.

What is the the difference between 1,2,3 and I, II, III. With Class 1,2...this is in reference to these types of building structures. This type of Class(s) and there is not (is no mention of this)any mention in our 70 Code; it's a building code, reference. FYI Class only is in index in respects to Hazardous I,II, etc.
Schoolme please, I'm so Bored!!!!

Hmm, I'll bet 8 out of 10 electricians would fail Building Classification 1,2, and understanding their subdivisions.

More Fuel for the Mike Holt Submitting Machine!

I agree with you on chapters 1-4 generally apply to everything unless something in 5-7 modifies those requirements. Chapter 8 generally is independent of chapters 1-7 but not always/not entirely. One example: if running chapter 8 wiring inside raceways you need to go to chapters 1-7 to determine the requirements for the raceways.

I don't know how you got onto the hazardous location topic. I don't think hazardous locations were mentioned in the OP.

The mentioned class 2 or 3 in the OP was referring to class 2 or class 3 remote control, signaling or power limited circuits - which art 725 contains most of the modifications to chapters 1-4 that apply to those types of circuits. I guess OP could have been a little more clear as to just what he meant when mentioning class 2 or 3 as he didn't actually mention power limited circuits, but he did mention "control cable" which kind of prompts most to think power limited and not hazardous location.