Protection Against Physical Damage

[finhead]

I don't understand the relationship between Sections 230.43 and 230.50. Are these Sections saying:

A. The wiring methods permitted in 230.43 are acceptable if the service-entrance conductors are not exposed to physical damage, but where service-entrance conductors are exposed to physical damage only the wiring methods permitted in Section 230.50(B)(1) are acceptable or:

B. Wiring methods sited in Section 230.43 are acceptable in locations exposed to physical damage; Sections 230.50(B)(1) and (B)(2) apply only to service cables, individual open conductors, etc., and shall be protected as per 230.50(B)(1) where exposed to physical damage.
I need help

Thanks in advance for your input
Brian Dolan

 

[don_resqcapt19]

Brian,
In my opinion your answer A is correct. The real issue with the application of these sections becomes, 'what is exposed to physical damage". In my opinion if you can see the wiring method, it is exposed to physical damage, but that is not to say that a concealed wiring method is not also exposed to physical damage.

 

[dnem]

I don't understand the relationship between Sections 230.43 and 230.50. Are these Sections saying:

A. The wiring methods permitted in 230.43 are acceptable if the service-entrance conductors are not exposed to physical damage, but where service-entrance conductors are exposed to physical damage only the wiring methods permitted in Section 230.50(B)(1) are acceptable or:

B. Wiring methods sited in Section 230.43 are acceptable in locations exposed to physical damage; Sections 230.50(B)(1) and (B)(2) apply only to service cables, individual open conductors, etc., and shall be protected as per 230.50(B)(1) where exposed to physical damage.
I need help

Thanks in advance for your input
Brian Dolan

Let's put an example on this question and see which is right. . Example will be SE cable in an area exposed to physical damage.

A. The wiring methods permitted in 230.43 are acceptable if the service-entrance conductors are not exposed to physical damage, but where service-entrance conductors are exposed to physical damage only the wiring methods permitted in Section 230.50(B)(1) are acceptable or:

If A is correct, you can't use SE where exposed to physical damage because it's not on the 230.50(B)(1) list.

B. Wiring methods sited in Section 230.43 are acceptable in locations exposed to physical damage; Sections 230.50(B)(1) and (B)(2) apply only to service cables, individual open conductors, etc., and shall be protected as per 230.50(B)(1) where exposed to physical damage.

If B is correct, you can use SE if it is contained inside a raceway listed on the 230.50(B)(1) list.

338.12(A)(1) tells you that B is correct. . Notice the word "unless" used in 338.12(A)(1).

I'm sure you'll ask why 338.12(A)(1) refers you to 230.50(A) instead of referring you to 230.50(B)(1). . At first glace, 230.50(A) appears to be in conflict with 338.12(A)(2), which doesn't allow SE underground. . But 230.50(A) refers you to 300.5 which also covers aboveground. . 300.5 is the reference because 230.50(B)(1) could be used to require the raceway to be continuous from enclosure to enclosure. . 300.5 requires protection only up to 8' on the outside [300.5(D)(1)] and only up to building penetration [if SE enters building, 300.5(D)(2)]. . A common installation that I see in residential is an exterior meterbase and an interior basement main disconnect/panel. . Many times the contractor installs PVC out of the bottom of the meterbase, then a PVC LB, finally a sleave going thru the wall and ending in a bell on the inside. . He runs SE thru the PVC and once into the basement, runs it in the open and down into the panel. . 300.5(D)(2) + 300.12Ex1 specifically allow that installation and I consider it to be a high quality and aesthetically pleasing installation that also provides great SE flexibility for varying wall thicknesses and exact panel location in the basement.

 

[dnem]

The real issue with the application of these sections becomes, 'what is exposed to physical damage".

I agree. . This is something open to interpretation but I see this as related to requiring bollards and rigid pipe around vehicular traffic [110.26(F)(2) + 450.8(A)]. . When you still have vehicular traffic closeby but not directly close enough so as to require bollards, that doesn't mean the rigid pipe would also not be required. . You might still have to install a "beefier" raceway such as listed in 230.50(B)(1) and required by 338.12(A)(1).

In my opinion if you can see the wiring method, it is exposed to physical damage,

That interpretation runs into some problems. . An example is when dealing with NM in 334.15, Exposed Work. . There are installations that require "Protection from Physical Damage" and they are listed in 334.15(B). . There are also other exposed installations that are not required to be protected and have their own code wording found in 334.15(A).

[Then you have basement joists that follow neither 334.15(A) or (B) but are covered in (C), but that isn't applicable to this discussion.]

 

[don_resqcapt19]

David,
I stand by my statement that if you can see it you can damage it.

 

[JJWalecka]

I have a question. 230.50 Protection against Physical damage

230. 50 (B2) Other than Service cable individual open conductors and cables, other than service cables, shall not be installed within 3.m (10 ft) of grade level or wher exposed to physical damage.

Does that imply that cables over ten feet are not exposed to physical damage?

JJ

 

[kapakahi]

Protection against Physical damage is a vague statement and it comes up numerous times in the code.

A #6 ground wire needs no further protection against physical damage (it only has to be secured to the construction)however, larger than #6 and it has to be "Protection against Physical damage."

In the 2005 NEC Handbook regarding UF Cable 340.12 it states, "Type UF cable suitable for exposure to the direct rays of the sun is indicated by tag marking and marking on the cable surface with the designation `Sunlight Resistant.' This physical protection requirement ensures that Type UF cable, as it emerges from underground, is protected from physical damage."

From here we see the the term "protected from physical damage" means from sunlight since having the sunlight resistant rating provides it with "protected from physical damage."

 

[dnem]

I have a question. 230.50 Protection against Physical damage

230. 50 (B2) Other than Service cable individual open conductors and cables, other than service cables, shall not be installed within 3.m (10 ft) of grade level or wher exposed to physical damage.

Does that imply that cables over ten feet are not exposed to physical damage?

JJ

No, it means that all individual open conductor installations under 10' are stated as "shall not". . No other questions/answers are needed. . Individual open conductor installations under 10' = NO.

Individual open conductor installations over 10' are a maybe. . Maybe allowed, maybe not allowed. . It all depends on if they are considered "exposed to physical damage".

 

[dnem]

Protection against Physical damage is a vague statement and it comes up numerous times in the code.

A #6 ground wire needs no further protection against physical damage (it only has to be secured to the construction)however, larger than #6 and it has to be "Protection against Physical damage."

In the 2005 NEC Handbook regarding UF Cable 340.12 it states, "Type UF cable suitable for exposure to the direct rays of the sun is indicated by tag marking and marking on the cable surface with the designation `Sunlight Resistant.' This physical protection requirement ensures that Type UF cable, as it emerges from underground, is protected from physical damage."

From here we see the the term "protected from physical damage" means from sunlight since having the sunlight resistant rating provides it with "protected from physical damage."

damage from trucks, 225.18(2)
damage from backfill material, 300.5(F)
damage from earth movement, 300.5(J)
damage from sunlight, 300.6(C)(1)
damage from chemicals, 300.6(C)(2)
damage from vehicles, 110.26(F)(2)
damage from spilled liquids, also 110.26(F)(2)
damage from anything harder than rigid pipe, 230.50(B)(1)

It's a huge category open to endless interpretation, discussion, and disagreement. . It's also not the best one to get uniform code interpretation from various inspectors.

A #6 ground wire needs no further protection against physical damage (it only has to be secured to the construction)however, larger than #6 and it has to be "Protection against Physical damage."

I remember years ago reading thru 250.64(B) over and over again and not getting it. . It just wouldn't "click". . I caouldn't understand if you have 2 options: exposed to physical damage and not exposed to physical damage, how can you end up with 3 categories ?

After a while it finally dawned on me.
A] . 4 + larger
B] . 6
C] . smaller than 6

A] 4 + larger: only protect where exposed to physical damage
B] 6: protect where either exposed to physical damage or where not run along surface of the building [a midair section]
C] smaller than 6: always protected