Expansion fittings - again

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electrofelon said:
So does the factory made version. All it is is a piece of 2.5 with the end heated and shrunk down into a 2" ta.
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electrofelon said:
..... I don't see how that is any different than using the fitting infinity linked to.
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They got it listed for the purpose, makes it sell for more as well. Other then that is is not any more or less effective.

I do believe it must be used in a vertical position with threaded end up where most any other expansion fitting could be used in any orientation.
 
Here frost heaves aren't an issue and in NFPA 13 sprinkler code there is a reference to undisturbed earth for thrust blocking. I have used this as a guide if the ground is stable and undisturbed I accept it without an expansion fitting. If it would be allowed for large pipe under 200 lb pressure it should be ok for electrical pvc.
 
peter d said:
This will blow your mind - I pay around $15.xx for a 1.25", 1.5" and 2". :blink: Basically the same price for those three sizes and I pay around the same price you mentioned for a 1/2" one as well. There is no consistency with their pricing at all.
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same as furnace filters. a 3M red one in 12x12 costs the same as a 16x25 or any other much larger size.
 
electrofelon said:
Is an expansion fitting required to be listed for the purpose?
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Possibly a good question.

Is a 2.5" TA and short piece of 2.5" PVC an expansion fitting? Is is a reducing fitting? I think what purpose something is listed for has some importance, otherwise you can take anything that is listed and use it for anything you want and just say "but it is listed".

I have seen 1/2 flexible metal conduit fittings used to terminate 3/4 EMT many times - they work reasonably well - but not listed for that use either, would you accept that install?
 
kwired said:
Possibly a good question.

Is a 2.5" TA and short piece of 2.5" PVC an expansion fitting? Is is a reducing fitting? I think what purpose something is listed for has some importance, otherwise you can take anything that is listed and use it for anything you want and just say "but it is listed".

I have seen 1/2 flexible metal conduit fittings used to terminate 3/4 EMT many times - they work reasonably well - but not listed for that use either, would you accept that install?
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We can certainly get into lots of disagreements and opinions on the topic of things being listed for a use or purpose.


What are some examples in the nec of the phrase "listed for the use" or "purpose" ? I know I have heard that phrase often but upon thinking about it, I couldn't think of any examples off the top of my head.
 
electrofelon said:
...What are some examples in the nec of the phrase "listed for the use" or "purpose" ?...
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314.3 Ex2 Nonmetallic boxes with metal raceways or armored cable.

314.41 metal box covers.

334.17 NM framing grommets.

342.42/344.42 threadless fittings on threaded conduit ends.

362.10(7) ENT fittings for wet locations indoors or embedded in concrete.

Need more?
 
RICK NAPIER said:
Here frost heaves aren't an issue
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Today I learned NJ is much warmer than I thought. :huh:


and in NFPA 13 sprinkler code there is a reference to undisturbed earth for thrust blocking. I have used this as a guide if the ground is stable and undisturbed I accept it without an expansion fitting. If it would be allowed for large pipe under 200 lb pressure it should be ok for electrical pvc.
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I don't think we can compare metal water pipe to PVC. Maybe if the topic was expansion fittings for RMC.

In my opinion PVC conduit is much more prone to pulling out of fittings due to earth movement than any metal conduit or pipe.
 
iwire said:
Today I learned NJ is much warmer than I thought. :huh:




I don't think we can compare metal water pipe to PVC. Maybe if the topic was expansion fittings for RMC.

In my opinion PVC conduit is much more prone to pulling out of fittings due to earth movement than any metal conduit or pipe.
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What I'm looking at is earth movement. The issue in NFPA 13 is whether the weight of a 18" block of concrete (or larger) will move in the earth. My opinion was if that concrete block was not going to cause settling in the soil the weight of an electrical PVC conduit was not going to cause settling. Also I'm in South Jersey and frost heaves have not been a problem.
 
RICK NAPIER said:
What I'm looking at is earth movement. The issue in NFPA 13 is whether the weight of a 18" block of concrete (or larger) will move in the earth. My opinion was if that concrete block was not going to cause settling in the soil the weight of an electrical PVC conduit was not going to cause settling. Also I'm in South Jersey and frost heaves have not been a problem.
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Do.they.not.require.building.footings.to.be.deeper.then.maximum.frost.depth?

I have heard of this space bar failure issue on this site, first time it has happened to me.
 
RICK NAPIER said:
What I'm looking at is earth movement. The issue in NFPA 13 is whether the weight of a 18" block of concrete (or larger) will move in the earth. My opinion was if that concrete block was not going to cause settling in the soil the weight of an electrical PVC conduit was not going to cause settling. Also I'm in South Jersey and frost heaves have not been a problem.
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kwired said:
Do.they.not.require.building.footings.to.be.deeper.then.maximum.frost.depth?

I have heard of this space bar failure issue on this site, first time it has happened to me.
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Not so much the building foundations but the water line being below frost depth. Given the horizontal underground portion should be below the frost line, any frost acting on the riser will just be acting on the riser only.

With underground PVC runs, the horizontal portion of the run may be and often is within the frost zone. It will move up and down with the frost as it acts on the soil at the depth of the conduit's horizontal run. The building the equipment at the upper end of the riser is attached to above does not move with the frost below... as the equipment is attached to the building setting on a footing below frost level.
 
Smart $ said:
Not so much the building foundations but the water line being below frost depth. Given the horizontal underground portion should be below the frost line, any frost acting on the riser will just be acting on the riser only.

With underground PVC runs, the horizontal portion of the run may be and often is within the frost zone. It will move up and down with the frost as it acts on the soil at the depth of the conduit's horizontal run. The building the equipment at the upper end of the riser is attached to above does not move with the frost below... as the equipment is attached to the building setting on a footing below frost level.
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That is what I was trying to get at, but you sort of dismissed at the beginning of your post then said it later:huh:

If building footings are not below frost level then the entire building can be damaged by frost heave.
 
kwired said:
That is what I was trying to get at, but you sort of dismissed at the beginning of your post then said it later:huh:...
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But I didn't entirely dismiss what you were trying to get because I knew I was going to try and get at it on my own... :D;):p
 
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