Sch 40 to Sch 80...

[1793]

I have a job coming up where the 3/4" Sch 40 PVC is underground. Where it emerges above grade I will be moving over to Sch 80 for about 12". My dilemma, the conduit fill is fine for the Sch 40 but for the Sch 80 is "over filled" by .0092

Do I need to rethink the conduit size needed for the entire run or let it "ride"?

 

[Pierre C Belarge]

Norb
So close, yet so far.

These are the type of questions that can plague an inspector who cares about the well being of a contractor.

How long is the run of Schedule 40?
Is it already buried?
Can you use a different raceway method to protect the emerging pipe?

 

[1793]

Norb
So close, yet so far.

These are the type of questions that can plague an inspector who cares about the well being of a contractor.

How long is the run of Schedule 40?
Is it already buried?
Can you use a different raceway method to protect the emerging pipe?

75'
Partially
No I don't think so.

 

[masterinbama]

Not having a book handy could you install a cee condulet and call the 12"of schedule 80 a nipple? We don't use any sch. 80 here so I'm fuzzy on the regs for it. Or maybe 12"of GRS and put a bonding bushing on it.

 

[TOOL_5150]

Why cant you switch over to rigid or IMC?

~Matt

 

[Twoskinsoneman]

Are all of the wires the same size?

Chapter 9 table note (7) could allow it.

 

[1793]

Are all of the wires the same size?

Chapter 9 table note (7) could allow it.

I'm pulling 3 #6 and 1 #10 for a panel in a Garage. I will be driving ground rod(s) at the Garage.

 

[1793]

Why cant you switch over to rigid or IMC?

~Matt

I only need a short section of "protection" and then back to flexibility. I really don't want to add a bunch of boxes or fittings for the change-over.

 

[TOOL_5150]

I only need a short section of "protection" and then back to flexibility. I really don't want to add a bunch of boxes or fittings for the change-over.

Ok I hear ya. FWIW, Id check with the AHJ and see if they will let it slide. What was it, something like .0092 over? thats not that much.


~Matt

 

[resistance]

I only need a short section of "protection" and then back to flexibility. I really don't want to add a bunch of boxes or fittings for the change-over.

You have a number of options I'm sure, but when you say short section, how long is this section?

 

[markstg]

I have a job coming up where the 3/4" Sch 40 PVC is underground. Where it emerges above grade I will be moving over to Sch 80 for about 12". My dilemma, the conduit fill is fine for the Sch 40 but for the Sch 80 is "over filled" by .0092

Do I need to rethink the conduit size needed for the entire run or let it "ride"?

Set your calculator to round off to 1 decimal place.

 

[ptrip]

Set your calculator to round off to 1 decimal place.

Then have this thread deleted! :wink:

 

[hardworkingstiff]

Why cant you switch over to rigid or IMC?

~Matt

This sounds like a good plan.

 

[Twoskinsoneman]

Why don't you use a reducer to finish the run with 1" where you need to have sched 80?

 

[Pierre C Belarge]

You have a number of options I'm sure, but when you say short section, how long is this section?[/quote]


Just short enough not to be too long.

 

[ultramegabob]

Resistance, it looks like approx 12", I would guess it will be along the foundation where it is exposed before it re-enters the building.

Where it emerges above grade I will be moving over to Sch 80 for about 12".

 

[ohmhead]

I have a job coming up where the 3/4" Sch 40 PVC is underground. Where it emerges above grade I will be moving over to Sch 80 for about 12". My dilemma, the conduit fill is fine for the Sch 40 but for the Sch 80 is "over filled" by .0092

Do I need to rethink the conduit size needed for the entire run or let it "ride"?

Well we due lots of underground and i mean lots the specs on the job say when you stub though from below grade you must use rigid conduit this means imc or rigid not pvc rigid if it said rigid pvc then you could .

most commercial slabs stub ups are done in imc and painted do to the fact that most commercial jobs dont like that pvc above slab in the event of a fire that pvc smoke is not acceptable its a fire issue also not just a conduit fill .

I can only see the NEC code here you can not over fill the conduit .
And read your specs but on the mike holts forum we must go by the rules at least when i come on they make me go by the book !
Take care

 

[jimman]

Is the area actually exposed to physical damage? If not, talk to the AHJ. Usually, they have "guideline" of sch 80 where emerging from grade, but "exposure to physical damage" may be dabated. Otherwise, I have seen reducers to change from 1" to 3/4" for the short section.

 

[Twoskinsoneman]

Otherwise, I have seen reducers to change from 1" to 3/4" for the short section.

Now there's a heluva great idea!

 

[wawireguy]

I'd just run 1" the whole way.. Doesn't cost that much more..