conduit fill for SER cable?

[Innovate1]

I am planning to add a 50A RV receptacle and have AL 6-6-6 with 6 ground with OD of 0.717". Will be using Sch 40 conduit for protection from the attic down the wall to the receptacle. It fits loosely in 3/4 PVC conduit but not sure it meets code due to fill. I read someones opinion (not on this site) that since it isn't continuous conduit the 53% fill limit doesn't apply but not sure that's true.

Running the numbers with 3/4" sch 40 PVC it is 76% fill and with 1" it is 47% fill. Do I need 1" conduit or is 3/4 ok?

 

[wyliesdiesels]

SER doesnt need to be in conduit unless its subject to damage. doesnt sound like your install would be. I would just skip the conduit, especially PVC, and just run the SER. if you must use conduit, individual conductors would be far cleaner and easier. Could use #8 cu THWN w/ a #10 green ground

 

[Innovate1]

I don't think #8 AL is good for 50A at 75C. You must have been considering copper.
Maybe SER on the wall of a garage would be considered NOT subject to damage - not sure about that one. Figured it would look better in conduit and I already have the wire. I am not running conduit the whole way and this way I don't need any junction boxes. Doing a bit more searching on this I think a 60% limit applies if the sleeves are 24" or less (mine are much longer) so technically I think 1" is required.

 

[Innovate1]

Can anyone answer my original question on what is the minimum size PVC conduit? Want to confirm I have the code rules correct.

 

[bronc076]

Found this chart and a calculator that may help.

https://electricalestimating101.com/wp-content/uploads/2019/06/NEC-Table-C-Combined-Conduit-Types-THHN-XHHW.pdf

and

Conduit Fill Calculator | Southwire

Get accurate conduit fill percentages with Southwire's Conduit Fill Calculator. Perfect for electricians, engineers, and contractors.

www.southwire.com

 

[mike93lx]

Afaik, the 60% fill only applies up to 24", as you noted. after that, I would assume that normal fill rules apply.

I'd just follow the normal fill rule especially since it's a short run. Guessing one 10' stick does it?

 

[Bert_]

I would definitely do 1" just from experience

 

[Bert_]

SER doesnt need to be in conduit unless its subject to damage. doesnt sound like your install would be. I would just skip the conduit, especially PVC, and just run the SER. if you must use conduit, individual conductors would be far cleaner and easier. Could use #8 THWN w/ a #10 green ground

Ser left exposed outside does not hold up well. I always sleeve exterior portions of a run and would recommend the same to anyone else.

 

[Innovate1]

Ser left exposed outside does not hold up well. I always sleeve exterior portions of a run and would recommend the same to anyone else.

Guess I wasn't clear that this is inside. Putting it just inside the OHD. That way I don't have to worry about weatherproof cover. It's running up the inside of a finished wall.

And yes on one 10' stick being enough.

 

[mike93lx]

Ser left exposed outside does not hold up well. I always sleeve exterior portions of a run and would recommend the same to anyone else.

SER (I guess actually SEU) running on the outside of a house is very common where I grew up in New england, including the house I used to own as well as my folks. Seemed to do ok. What issues have you encountered with it?

 

[Bert_]

SER (I guess actually SEU) running on the outside of a house is very common where I grew up in New england, including the house I used to own as well as my folks. Seemed to do ok. What issues have you encountered with it?

The outside coating gets brittle. Cracks if you even breathe on it.

 

[sparky 1971]

Just use 1" and be done with it.

 

[sparky 1971]

SER (I guess actually SEU) running on the outside of a house is very common where I grew up in New england, including the house I used to own as well as my folks. Seemed to do ok. What issues have you encountered with it?

We have a local amendment that all service entrance conductors have to be in metal conduit. Ain't running no SEU or SER on the outside walls around here. I just follow that train of thought no matter what jurisdiction I'm in.

 

[wyliesdiesels]

I don't think #8 AL is good for 50A at 75C. You must have been considering copper.

correct i was referencing copper. sorry i wasnt clear

 

[Innovate1]

Afaik, the 60% fill only applies up to 24", as you noted. after that, I would assume that normal fill rules apply.

I'd just follow the normal fill rule especially since it's a short run. Guessing one 10' stick does it?

And I don't meet 60% anyway. So 1" is it. Although I have seen people claim that raceways used for physical protection don't have fill limits I am guessing that is wrong.

 

[mike93lx]

And I don't meet 60% anyway. So 1" is it. Although I have seen people claim that raceways used for physical protection don't have fill limits I am guessing that is wrong.

The internet claims a lot of things. Like Nm can't go in conduit

I go back to the part about it only being a single stick. $10 for 3/4, $14 for 1, and $19 for 1-1/14. I'd be making my job as easy as possible at those prices