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Old 08-12-2008, 08:03 PM   #16
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If you don't know the answer, please don't respond with "because thats what the code says... duh."

If you don't know why and don't care... fine, don't get irritated with those of us who are curious. There has to be a reason it is in the code, its not like they just sat around and decided "lets force them to use grey PVC because we like grey better than white". There are times where the "why" does matter. Say you just found that the previous owner of the house buried a ton of wire in white PVC or in the OPs case, a mistake that is not easily rectified. . So you have to ballance the "WHY" with the effort to fix. If the grey has something added to it to make it significantly safer or the white presents a significant safety risk, then the inspectors should have forced the OP to replace it. If there is no significant safety reason, and its only for identification purposes or a marginal safety issue, it would defy common sense to bust up the slab to tear it out. There are always exceptions to the rule, and if you don't understand the "WHY" of the rule, you won't know how to determine the acceptable exceptions.

If you are content to turn off your brain and never ask "WHY", don't get pissy with those of us who care about the "WHY"
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Old 08-12-2008, 09:36 PM   #17
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Quote:
Originally Posted by daxinarian View Post
If you don't know the answer, please don't respond with "because thats what the code says... duh."

If you don't know why and don't care... fine, don't get irritated with those of us who are curious. There has to be a reason it is in the code, its not like they just sat around and decided "lets force them to use grey PVC because we like grey better than white". There are times where the "why" does matter. Say you just found that the previous owner of the house buried a ton of wire in white PVC or in the OPs case, a mistake that is not easily rectified. . So you have to ballance the "WHY" with the effort to fix. If the grey has something added to it to make it significantly safer or the white presents a significant safety risk, then the inspectors should have forced the OP to replace it. If there is no significant safety reason, and its only for identification purposes or a marginal safety issue, it would defy common sense to bust up the slab to tear it out. There are always exceptions to the rule, and if you don't understand the "WHY" of the rule, you won't know how to determine the acceptable exceptions.

If you are content to turn off your brain and never ask "WHY", don't get pissy with those of us who care about the "WHY"
Nobody was getting pissy up until your post.

By the way, Chris75 did say "I don't know" what the difference is, so maybe your post was directed more to me...

I wholeheartedly agree with the desire to know the "why" of things, but the point that was being made was that the NEC is a living document, constantly being revised (although not always making sense), and it is best to become familiar with it and accept the rules contained therein. The OP certainly went about the project in the right way - learning, questioning, getting an inspection.

Why don't you call the manufacturer of the white PVC pipe and ask them why it is not UL listed as an electrical conduit? There's gonna be your best answer.

Here's mine:

1) It's not gray PVC. It is PVC conduit, which happens to be gray in color. PVC conduit is intended to to carry electrical conductors. It is not white PVC, it is PVC water pipe, which happens to be white. It is intended to carry water, sometimes under pressure, sometimes as waste or drain pipe only. Both are manufactured with specific uses in mind. Can you tell the most important difference yet?

Can you stop here, and accept that answer? At what level of explanation can you end your reluctance to do the right thing (and use proper conduit, direct burial cable, concrete coverings, aerial cables, or another method in full compliance with the NEC)?

2) The white PVC would have been able to be used as a "sleeve" as briefly touched upon by COW's post, but only if those tight bends weren't there, the conductor/cable was rated for direct burial, and NEC depth and cover requirements were met, and with the inspector's understanding of what was being accomplished.

3) In the OP, the white PVC is not yet considered electrical in nature. It is just a run of plumbing pipe at this point, so it is not an existing electrical circuit which the OP wants to deal with.

It is a new installation, and you are required to meet the codes when you choose to install electric wiring and equipment. The OP intends to put wiring in it and hook it up to the electrical system - now it becomes an issue.

4) The inspectors did cut the OP some slack, although they weren't required to.
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Old 08-12-2008, 09:59 PM   #18
 
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Quote:
Originally Posted by daxinarian View Post
If you don't know the answer, please don't respond with "because thats what the code says... duh."

If you don't know why and don't care... fine, don't get irritated with those of us who are curious. There has to be a reason it is in the code, its not like they just sat around and decided "lets force them to use grey PVC because we like grey better than white". There are times where the "why" does matter. Say you just found that the previous owner of the house buried a ton of wire in white PVC or in the OPs case, a mistake that is not easily rectified. . So you have to ballance the "WHY" with the effort to fix. If the grey has something added to it to make it significantly safer or the white presents a significant safety risk, then the inspectors should have forced the OP to replace it. If there is no significant safety reason, and its only for identification purposes or a marginal safety issue, it would defy common sense to bust up the slab to tear it out. There are always exceptions to the rule, and if you don't understand the "WHY" of the rule, you won't know how to determine the acceptable exceptions.

If you are content to turn off your brain and never ask "WHY", don't get pissy with those of us who care about the "WHY"

Were talking about electrical conduit hear. not why the earth revolves on its axis, if you really need to know why electrical conduit is required to be listed its probably because of the fact that the conduit itself must hold up to certain requirements to protect the conductors inside...

Rigid Nonmetallic Conduit has a list of Uses Permitted and Not Permitted, I dont know what plumbing pvc is listed for, nor do I care, but get real guys, use the right material or dont do the job and hire a pro.... I dont need to hear well I used to wrong material but I'm gonna justify the cause...
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Old 08-12-2008, 11:35 PM   #19
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Sorry for the previous and following rant, but...

The reason I am irritated is not because I want to cut corners, or save money or anything like that and I have no reluctance to "do the right thing". I will strictly adhere to NEC code unless it is completely impractical or inappropriate, even the code recognizes this by "grandfathering" in most situations. One of my pet peeves is people who can't think past a piece of paper or who let paper do their thinking for them. Often times you have to fix what someone else screwed up. If you are smart and understand the reasoning behind things (and get an inspector who is equally smart) you can come up with a cost effective practical solution that is safe (and sometimes safer than what code requires). Imagine you bought a house and only later discovered that one wire was done in non-electrical PVC and it goes all the way across your slab... Would you practically destroy your whole house jackhammering out all that concrete simply to replace that discrepant PVC?

Now I am not arguing that any color PVC is ok to use. I would just like to know what is different about electrical PVC vs standard Plumbing PVC. Is there an actual physical/chemical difference apart from the color?
Is the electrical PVC more fire resistant?
Does it have electrical shielding properties?
Is it more/less conductive?
Is it resistant to static charge?
Is it more resistant to sunlight?

And yes, I know I am being a PIA, but I have a low tolerance for people who let others do their thinking for them.
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Old 01-11-2010, 03:11 PM   #20
 
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I know this is an old post


I just hate to see inadequate or short sided information. First of all the NEC is a sub-set of the NFPA, and the sole purpose is to provide rules that provide personnel and property protection. Are you ready for a shocker. You do not have to follow the NEC. You can always opt to have a licensed professional engineer prepare an analysis, and this will allow you to throw away the NEC, and still pass inspection. This is a very costly approach, so most just follow the NEC. In the front of the NEC it tells you many applications where the NEC does not apply, such as industrual complexes like power plants, because they always use seperate engineering analysis.

To answer the question. PVC pipe may be used in place of PVC conduit if the PVC pipe has been manufactured to meet safety requirements on flame and temperature resistance, which it probably was. With that said, PVC water pipe is thicker (for pressure) than PVC conduit, so the outer diameter is the same, but the inner diameter of water pipe is smaller, which means the internal area is less. Therefore, the size of the PVC conduit (outer dimension) needed to accomidate the number of conductors (cables) will not match the calculated percent fill for pulling cable that is provided in the NEC. If you use PVC water pipe then you have to increase the size used over the size listed in the NEC. Percent fill is used to calculate the temperature rating and ampacity of power cables. If the percent fill exceeds the assumptions used in the NEC, then the ampacity tables in the NEC are no longer valid. Such as a 20 Amp needing a 12 AWG conductor size. Also, PVC conduit fittings should be used with the PVC water pipe. The use of PVC water fittings will exceed the bend raduis of cable being pulled through. The percent fill assumption in the NEC is also based on what type and how many bends, so the cable pulling radius is acceptable. If the cable pulling bend radius is exceeded, then the cable sidewall pressure rating can be exceeded.

If the cable sidewall pressure is exceeded during the cable pull, then the cable insulation will be permantly damaged. Cable insulation damage will derate your cable, so it will not be able the carry the specified voltage or current. In this senario, the damaged cable would increase the chance that you could have a fire or personnal injury. And remember the purpose of the NEC is personnal and property protection.

The NEC provides a lot of easy to follow information based on a set of assumptions. When those assumptions are changed, the rest of the NEC information cannot be blindly applied. Changing the raceway affects the percent fill values, which changes the number of allowed conductors, the temperature rating, and the ampacity rating. All of these are very important.

I am a license master electrician and a licensed professional electrical engineer. The inspector should be a licensed master electrician, which would allow him to make some simple calculations based on the new information to determine if this installation will meet the intent of the NEC. In the construction industry, the use of the "Ugly" book would provide the formulas for these calculations.

Just to echo some of the other posts. As an inspector, I would not have passed this installation. But the reason would have been the use of PVC pipe fittings, verses PVC conduit fittings. The pipe / conduit itself makes no real difference.
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Old 01-11-2010, 04:00 PM   #21
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Originally Posted by electrical_guy View Post
I just hate to see inadequate or short sided information. First of all the NEC is a sub-set of the NFPA, .............................................
Was all this really necessary? I mean really?

A) NO, water pipe CANNOT be used in place of electrical conduit. Even if it could after the reviewing, studying and lab testing by a professional engineer and NASA, WHY BOTHER???
All this engineering mumbo-jumbo makes no sense in the context of this thread.

B) Pipe is conduit and conduit is pipe. SEMANTICS.

C) This thread is a year and a half old.

Fact is plumbing pipe and fittings CANNOT be used for electrical wiring. To suggests otherwise is just plain silly.
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Old 01-11-2010, 04:01 PM   #22
 
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Is seems to my that an obvious answer to why use the grey PVC is so that people can recognize immediately that it is an electrical service line and don't cut into it.
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Old 01-11-2010, 04:04 PM   #23
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Originally Posted by Cow View Post
What does matter is the fact white pvc pipe matches the gray pvc pipe sizes, so the couplings still fit.
Also, gray PVC conduit is UV resistant for use where subject to sun light. White PVC plumbing pipe is not UV resistant.
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Old 01-11-2010, 07:42 PM   #24
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Originally Posted by electrical_guy View Post
I just hate to see inadequate or short sided information. First of all the NEC is a sub-set of the NFPA, and the sole purpose is to provide rules that provide personnel and property protection. Are you ready for a shocker. You do not have to follow the NEC. You can always opt to have a licensed professional engineer prepare an analysis, and this will allow you to throw away the NEC, and still pass inspection. This is a very costly approach, so most just follow the NEC. In the front of the NEC it tells you many applications where the NEC does not apply, such as industrual complexes like power plants, because they always use seperate engineering analysis.

.
This is not necessaraly true In States that adopt the NEC through the General Assembly, so it becomes law. Thats why we are Code Enforcement Officers. You cant get an engineer to give you a letter to say you can drive greater than the speed limit can you?
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Old 01-12-2010, 12:10 PM   #25
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This is not necessaraly true In States that adopt the NEC through the General Assembly, so it becomes law. Thats why we are Code Enforcement Officers. You cant get an engineer to give you a letter to say you can drive greater than the speed limit can you?
sometimes I just can't help myself...

Actually, in some states you can. For instance in Texas the law is:
Sec. 545.351. MAXIMUM SPEED REQUIREMENT. (a) An operator may not drive at a speed greater than is reasonable and prudent under the circumstances then existing.
Now it is legally assumed that the posted limit is the maximum speed that is "reasonable and prudent" (sec. 545.352) But if you can prove that in this particular instance it was safe to travel faster (ie: road was improved from narrow 2 lane dead end to a wide divided 4 lane that was extended through an empty field and speed limit signs were never updated, true story) you get your ticket dismissed (and yes, this tactic has worked many times for many people.)

Now back to the my original point... if you don't know the "why" of a particular code or rating, you may end up wasting lots of time, and money without any real increase in safety, or you may mistakenly think that it is no big deal and burn your house down. In the OP's case, he replaced the sharp elbow with a long sweeping elbow (resolving that issue), I presume had a big enough pipe that fill was not an issue, it was burried under concrete (no UV issue), and it would have been prohibitvely expensive to rectify the situtation for no real increase in safety. The correct thing at this point in time (we don't have a time machine...) was to note it as being discrepant and then disposition the discrepancy "use as is" and continue on.
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Old 01-12-2010, 07:06 PM   #26
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Originally Posted by daxinarian View Post
sometimes I just can't help myself...

Actually, in some states you can. For instance in Texas the law is:
Sec. 545.351. MAXIMUM SPEED REQUIREMENT. (a) An operator may not drive at a speed greater than is reasonable and prudent under the circumstances then existing.
Now it is legally assumed that the posted limit is the maximum speed that is "reasonable and prudent" (sec. 545.352) But if you can prove that in this particular instance it was safe to travel faster (ie: road was improved from narrow 2 lane dead end to a wide divided 4 lane that was extended through an empty field and speed limit signs were never updated, true story) you get your ticket dismissed (and yes, this tactic has worked many times for many people.)

Now back to the my original point... if you don't know the "why" of a particular code or rating, you may end up wasting lots of time, and money without any real increase in safety, or you may mistakenly think that it is no big deal and burn your house down. In the OP's case, he replaced the sharp elbow with a long sweeping elbow (resolving that issue), I presume had a big enough pipe that fill was not an issue, it was burried under concrete (no UV issue), and it would have been prohibitvely expensive to rectify the situtation for no real increase in safety. The correct thing at this point in time (we don't have a time machine...) was to note it as being discrepant and then disposition the discrepancy "use as is" and continue on.
Dont come to NC with this attitude and many other states also. If you notice I stated that your statement was not necessarily true, did not say it was not a true statement everywhere.
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