ECN Forum Forums Code Related Discussion NEC & other Code issues schedule 40 pvc

Hello again, iwire. And to continue from my last post...

While I agree with you that the AHJ gets to determine what is "subject to physical damage" and what is not, 300.5(D(4) clearly states that "Where the enclosure or raceway is subject to physical damage [as determined by the AHJ, if you like ], the conductors SHALL be installed in rigid metal conduit, intermediate metal conduit, SCHEDULE 80 RIGID NONMETALLIC CONDUIT, or equivalent." I can't imagine that Sched. 40 would be considered "equivalent", or else they would not have specified Sched. 80.

What say ye now? I suppose you could still say that hey, if the AHJ says it's okay, then it's okay. True enough, as 90.4 does say "By special permission, the AHJ may waive specific requirements in this Code...." I, however, like to think of the Code as the MINIMUM for safety, and look to the AHJ to makes things maybe more strict, but not more lax. And I take seriously 90.5 "Mandatory Rules, Permissive Rules, and Explanatory Material" when it states that "Mandatory rules of this Code are those that identify actions that are specifically required or prohibited and are characterized by the use of the terms SHALL or SHALL NOT."

And that is my final answer......I think.
And I have stepped down from my soapbox....for now.

I do not follow you.

No bollards the raceway is subject to physical damage, and you must use 80 or metal.

Put bollards in front of raceway and now the raceway is not subject to physical damage. It is not 'still' exposed to physical damage.

90.4 does not enter into this.

Bollards are often used to protect electrical equipment from physical damage.

If I had a raceway that was exposed to physical damage and then I built a wall around it would you still say it was exposed to physical damage just because it used to be exposed to damage?

The bollards do the same thing, assuming they are placed correctly and that would be up to the inspectors discretion.

At least that is how I see it.

Bob

[This message has been edited by iwire (edited 10-02-2005).]

I agree with you, Bob. It has just taken me a little time to get used to the idea of bollards - common, i guess, in other areas, but not familiar to me. I'm coming around, though, and can see that bollards and such would make the Schedule question irrelevant. Thanks.

anybody want to predict the price of pvc in about a month from now?
its going though the roof and most suppliers around here(wa) say they arent even taking orders right now because of katrina.

for what its worth.

h20

iwire ---

"The 'definition' or determination of exposed to physical damage is entirely up to the inspector / AHJ."

I disagree: The design engineer is the only person who can make that determination. The AHJ can require that engineering if he wishes.

George, I never understand you position.

An engineer can design anything they want.

If the inspector looks at it and says that schedule 40 is exposed to physical damage something will change.

Either the location or the schedule 40 but the inspector can fail it regardless of what an engineer may feel is OK.

Bob

I agree with Bob. An engineer may be able to cite some obscure data and calculations that say the raceway can sustain the likely physical threat but whether it is "exposed" to that threat is going to be the AHJs call.

The code is complicated enough, we don't need to legislate common sense. These things do seem to be a local decision though. As long as everyone locally is on the same page it is fair. The confusion starts when 2 inspectors, working for the same AHJ, don't agree. Then you are timing your inspections based on the inspector's days off

I'm reviving this thread in the hope to learn something. If you were the AHJ:

would schedule 40 PVC between the bottom of the trench and the LB on the wall of a home be "subject to physical damage"?


What about if it is shielded at ground level to protect it from power lawn care equipment.

How about when adjacent to a residential driveway.

I' not being a gadfly here but rather trying to get a sense of were others would come out on this issue. I ask because if everything from one and one half under to eight feet over ground level needs to be schedule 80 I will have to size the runs based on the interior diameter of schedule 80 unless I install a ground box to change conduit types.
--
Tom Horne

[This message has been edited by tdhorne (edited 11-09-2005).]

Bob,

I think that you might know me by now. ( Even though we never met) However if I see a piece of sch 40 PVC and it is all above the grade and not subject to physical damage, than as a AHJ, I would have to pass that job. If I were to allow a piece of SEU because it meets the code, then a piece of PVC would also fit the bill. This is just my 2 cents.

iwire ---

You seem to insist that the AHJ is the only person who has the ability to decide issues such as "likely to be subject to damage." I think that engineers are better positioned to make that decision.

I am just an engineer. I am liable for the work I do. NO ONE tells me to change my plans and material specs unless they accept ALL of my liability.

If you and your office wish to accept full liability for my work, I will allow you to require make decisions about this issue. Until then it is up to me and me alone to decide.

edited to add:

I have no objection to the NEC including a definition of "likely to be subject to damage." That definition might include above ground when outside of the building envelope. If that definition is included in the NEC, while I might oppose the definition, I will follow it.

[This message has been edited by George (edited 11-10-2005).]