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Old 09-27-2013, 10:07 PM   #61
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Burying Conduit


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Originally Posted by k_buz View Post
I'd like to see that code. I've never failed a PVC installation and I have only used expansion fittings once...on a rooftop.
No problem...



This PVC raceway for service lateral conductors has come apart at the connector because it was not designed with the correct transition or expansion fitting. As noted in 300.5(J), “Where direct-buried conductors, raceways, or cables are subject to movement by settlement or frost, direct-buried conductors, raceways, or cables shall be arranged so as to prevent damage to the enclosed conductors or to equipment connected to the raceways.” An Informational Note adds, “This section recognizes ‘S’ loops in underground direct burial to raceway transitions, expansion fittings in raceway risers to fixed equipment, and, generally, the provision of flexible connections to equipment subject to settlement or frost heaves.”



I work in Connecticut and New York, slip fittings ARE required on ALL underground services, and I install them on ALL transitions from pvcs emerging from the ground, the frost causes havoc to any fixed equipment, this is a no brainer... In the picture I posted they got off easy, when the PVC pushes up through the bottom of the meter can is when it's a fun day....


Last edited by stickboy1375; 09-27-2013 at 10:18 PM.
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Old 09-27-2013, 10:41 PM   #62
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Burying Conduit


I'm, by far, not a code expert, but I don't see anything in your quoted code that requires expansion fittings.

I understand what you are saying, however, unless there is a specific state amendment an inspector would have a hard time providing a code reference.
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Old 09-27-2013, 10:43 PM   #63
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Burying Conduit


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Originally Posted by k_buz View Post
I'm, by far, not a code expert, but I don't see anything in your quoted code that requires expansion fittings.

I understand what you are saying, however, unless there is a specific state amendment an inspector would have a hard time providing a code reference.
So how would you satisfy 300.5(J) ??? I've seen so many TA's blow through the bottom of meter cans, it's pretty obvious why it happened...

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Old 09-27-2013, 10:49 PM   #64
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Burying Conduit


Quote:
Originally Posted by k_buz View Post
I'm, by far, not a code expert, but I don't see anything in your quoted code that requires expansion fittings.

I understand what you are saying, however, unless there is a specific state amendment an inspector would have a hard time providing a code reference.
As noted in 300.5(J), “Where direct-buried conductors, raceways, or cables are subject to movement by settlement or frost, direct-buried conductors, raceways, or cables shall be arranged so as to prevent damage to the enclosed conductors or to equipment connected to the raceways.” An Informational Note adds, “This section recognizes ‘S’ loops in underground direct burial to raceway transitions, expansion fittings in raceway risers to fixed equipment, and, generally, the provision of flexible connections to equipment subject to settlement or frost heaves.”

I think an inspector would have no issues warranting a code violation in the OP's picture....
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Old 09-27-2013, 11:01 PM   #65
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You really can't cite the Info Note...its like failing due to voltage drop.

Now I ask you, have you ever seen a metallic expansion coupling? I haven't. I just googled it and it showed one manufacturer. What is the difference?
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Old 09-28-2013, 02:32 AM   #66
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Burying Conduit


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Out of curiousity, is there any difference between the breaker on the combo unit vs. the disconnect we have installed? Assuming both are rated for 200A service?
Nope. The same exact breaker. QOM2200VH

As for the expansion fitting, generally they are not enforced around here. The ground does not freeze that much in these parts ...

(But we DID get that earthquake last year!)
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Old 09-28-2013, 07:25 AM   #67
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Burying Conduit


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Originally Posted by k_buz View Post
You really can't cite the Info Note...its like failing due to voltage drop.

Now I ask you, have you ever seen a metallic expansion coupling? I haven't. I just googled it and it showed one manufacturer. What is the difference?


k-buz, do you not agree that the above picture is in fact in violation of 300.5(J)?

And I didn't say a slip fitting was your only option on dealing with 300.5(J), just the cheapest when dealing with PVC conduit.
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Old 09-28-2013, 07:40 AM   #68
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I actually don't think that particular picture is in violation of 300.5. The movement didn't cause damage to the conductors or the equipment connected to the raceway.

My particular hang up is the wording of the article...the word "arranged" in particular.
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Old 09-28-2013, 09:45 AM   #69
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Burying Conduit


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Originally Posted by k_buz View Post
I actually don't think that particular picture is in violation of 300.5. The movement didn't cause damage to the conductors or the equipment connected to the raceway.

My particular hang up is the wording of the article...the word "arranged" in particular.
So how do you think they satisfied 300.5(J) in the picture?
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Old 09-28-2013, 09:52 AM   #70
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I don't know as I can't see the conduit entering the ground, but it appears that it wasn't glued.
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Old 09-28-2013, 09:57 AM   #71
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Burying Conduit


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I don't know as I can't see the conduit entering the ground, but it appears that it wasn't glued.
Even if it was glued properly, how would that satisfy 300.5(J)?

You have a fixed structure with a moving conduit, something has to give, this is why 300.5(J) exist to begin with. If a conduit emerges from the earth which is going to move with frost heaves, then some type of installation has to be in place to accept this movement as to protect the equipment and conductors....
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Old 09-28-2013, 10:01 AM   #72
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(J) Earth Movement. Where direct-buried conductors, raceways, or cables are subject to movement by settlement or frost, direct-buried conductors, raceways, or cables shall be arranged so as to prevent damage to the enclosed conductors or to equipment connected to the raceways.



Lets look at this in a different view, how would one satisfy this requirement?
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Old 09-28-2013, 10:01 AM   #73
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That's my problem. It states it has to be "arranged", not installed. Arranged does note an installed.

It is a semantics issue in the wording that allows wiggle room. I do not disagree with the intent.
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Old 09-28-2013, 10:04 AM   #74
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Burying Conduit


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Originally Posted by k_buz View Post
That's my problem. It states it has to be "arranged", not installed. Arranged does note an installed.

It is a semantics issue in the wording that allows wiggle room. I do not disagree with the intent.

I don't disagree with your logic either, i just believe a slip fitting on PVC is the easiest solution to the requirement.

Our power company requires them on underground installs, which makes sense since meter cans were getting destroyed and causing fires. It's a simple liability fix.
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Old 10-02-2013, 12:07 PM   #75
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Burying Conduit


Wow! Great debate on the use of expansion couplings. As kbsparky stated, the ground doesn't freeze that frequently in these parts and even if it did my conduit is 30" deep, so frost heave shouldn't be an issue. I do have some concerns though about the PVC itself expanding and contracting. The two risers on this pedestal are VERY tight to the bottom of the boxes, especially the disconnect. There's literally zero room for movement, so if the PVC expands or contracts at all, I'm afraid the boxes are going to be damaged. I have the same concern about ground settlement in the trench.

Even though it sounds like the expansion fittings are not REQUIRED in my case, I'm starting to think that adding them can't hurt and would actually be cheap insurance. Well, I would need 3 fittings at $20 a piece, so maybe not that cheap. But certainly cheaper than having to make repairs after the conductors are already installed. Thanks to everyone for their input on this topic!!

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