safe cable installation

[CHARLIE VAN FLEET]

guys

does this cable installation keep it away from harm or damage as required

cvf

[Bill Kriegh]

This looks like flexible metal conduit as near as I can tell. Not allowed where subject to damage.

Depends where you're at in the area whether an electrical inspector would pass that - most wouldn't.

Common rule of thumb is that wiring types that are not allowed where subject to damage aren't allowed below 6 feet above the floor. It's not in the code book but it's generally what gets pushed by electrical inspectors.

I'm not sure how upset I'd be with it because the legally installed stuff behind the drywall can be damaged by running a 2 inch screw into the strap that holds the flex on, and, it's a lot harder to damage than NM-B.

Short answer - it doesn't fly

[Dom D'Agostino]

Around here it would likely be EMT or Sch 80 PVC, depending on who does it.

[Bill Kriegh]

Yeah, it usually is EMT. Here again, its open to opinions. EMT isn't supposed to be used where its subject to severe damage. "Severe" is no more defined than "regular" damage.

[Gunnar Alquist]

This looks like flexible metal conduit as near as I can tell. Not allowed where subject to damage.

Bill,

I was surprised to learn (a while back) that MC isn't allowed where subject to damage. I hadn't put flex into the same category, but I suppose it makes sense.

Is AC ok where subject to damage?

[CHARLIE VAN FLEET]

guys

is there a six foot above ground rule with flex because of damage--waiting to call city inspector monday

[Bill Kriegh]

Charlie, No written rule I'm aware of. The installation height is pretty much an inspector opinion. Opinion has a lot to do with how the space is used and might be used in the future.

There could be something local in an electrical code amendment but I've never seen one in the metro area. Have seen a lot of head shaking where flex is installed though.

Gunnar, No, AC not permitted where subject to damage. Article 302.12

[Gunnar Alquist]

Gunnar, No, AC not permitted where subject to damage. Article 302.12


Thanks Bill. But, in the California Electric Code, it's in 320.12.

:cool:

[Rollie Meyers]

Bill,

I was surprised to learn (a while back) that MC isn't allowed where subject to damage. I hadn't put flex into the same category, but I suppose it makes sense.

Is AC ok where subject to damage?

AC, MC, & NM cable are all prohibited where subject to physical damage.

[Jerry Peck]

Many places use 'to 8 feet', using a code section requirement as the basis for that 8 feet height protection from physical damage (I don't have my codes with me, I'm thinking 300.4/300.5 somewhere around there).

[Gunnar Alquist]

Many places use 'to 8 feet', using a code section requirement as the basis for that 8 feet height protection from physical damage (I don't have my codes with me, I'm thinking 300.4/300.5 somewhere around there).

Jerry,

Is this what you are referring to? It seems specific to direct-burial cable, but it does state 8'. I haven't found it elsewhere, but then again (unlike you) I don't read the NEC for pleasure. ;)

300.5(I) Emerging from Grade. Direct-buried conductors and cables emerging from grade and specified in columns 1 and 4 of Table 300.5 shall be protected by enclosures or raceways extending from the minimum cover distance below grade required by 300.5(A) to a point at least 2.5 m (8 ft) above finished grade. In no case shall the protection be required to exceed 450 mm (18 in.) below finished grade

[Jerry Peck]

Gunnar,

Yes, while that is specifically referring to "Direct-buried conductors and cables emerging from grade", it is also used by some/many as a definition for protection distance, below ground and above ground, from physical damage.

It would be good if the NEC gave a specific 'subject to physical damage' range, but there are so many variables to try to account for.

[Jim Port]

How many actually think that flex is going to get damaged given its location.?

[Jerry Peck]

How many actually think that flex is going to get damaged given its location.?

It only matters what two people think (one person really): 2) the electrical inspector; 1) the building official (if he thinks the electrical inspector is wrong). :first:

[Bill Kriegh]

How many actually think that flex is going to get damaged given its location.?

You'd be surprised what I've found "out there"

[Bill Kriegh]

Thanks Bill. But, in the California Electric Code, it's in 320.12.

:cool:

Yep. Somebody transposed a number.

[Jerry Peck]

You'd be surprised what I've found "out there"

In my garage ... that'd be subject to physical damage. :D

[david shapiro]

I've submitted multiple NEC proposals/ public inputs on the subject of "physical damage." It is a term of art, but one without a clear definition.

In one code cycle, I attempted to remove the term "physical." While the CMP did not respond that putting wiring at risk of emotional damage is prohibited, at the same time they did not provide a clear definition. However, their response seemed to suggest that they mean mechanical damage. In a subsequent cycle, I enumerated varieties of mechanical damage, and this was rejected on the ground that other physical damage such as overheating or chemical deterioration is included.

What it comes down to is a 110.12, or arguably a 110.3(A), only a version that inspectors may be more comfortable citing. The citation, after all, can only be validated or falsified after the fact.Somewhere in my archives I've a picture of horizontal 4 in EMT mounted outdoors about 10 ft up on a wall--and dinged, possibly by a truck. Is that a demonstration of physical damage? I'd say it's the very ding an sich.