WE HAVE RUN ABOUT 1500 FT OF #8 THROUGH PVC SCH 80 CONDUIT WITH PVC PULL BOXES SET EVERY 200 FT. Two knockouts were drilled through the bottom of the vertically installed and mounted boxes. Each 1.25 pvc male adapter was connected using sealing locknuts. Since we entered at the bottom of the box is this acceptable for wet locations and NEMA 3R ratings
PVC PULL BOXES
- Thread starter pageman
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peter d
Senior Member
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- New England
Re: PVC PULL BOXES
1500 feet of #8, huh? What exactly is the load that will be served by these conductors?
1500 feet of #8, huh? What exactly is the load that will be served by these conductors?
petersonra
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- Northern illinois
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- Semi-retired engineer
Re: PVC PULL BOXES
To answer your question, I would say no.
Unless I am misunderstanding your post, you have made a modification to the PVC box that was not envisioned by the manufacturer, nor tested by UL.
To answer your question, I would say no.
Unless I am misunderstanding your post, you have made a modification to the PVC box that was not envisioned by the manufacturer, nor tested by UL.
peter d
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- New England
Re: PVC PULL BOXES
Bob,
PVC boxes are sold without knockouts or openings. They are always field installed.
If we can't put any openings in them without voiding the UL listing, they are worthless.
I'm still curious as to what this #8 is serving.
Bob,
PVC boxes are sold without knockouts or openings. They are always field installed.
If we can't put any openings in them without voiding the UL listing, they are worthless.
I'm still curious as to what this #8 is serving.
Re: PVC PULL BOXES
The four #8 THWN are 3-phase, 460 volt with a ground serving a lift station for a landfill project. The motor is a 5 hp submersible pump. PVC pull boxes usually don't come with knockouts. Are drilled holes are on the bottom of the box. THe wires terminate into a control panel that controls the submersible pump and level switches. Environmental application.
The four #8 THWN are 3-phase, 460 volt with a ground serving a lift station for a landfill project. The motor is a 5 hp submersible pump. PVC pull boxes usually don't come with knockouts. Are drilled holes are on the bottom of the box. THe wires terminate into a control panel that controls the submersible pump and level switches. Environmental application.
friebel
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- Pennsville, N.J.
Re: PVC PULL BOXES
Openings on the bottom of a PVC junction box, is a great idea. When I worked for DuPont at a chemical plant, we would always put the openings on the bottom of PVC boxes for our heat tracing, systems, which would cover hundreds of feet.
The reason for this is that rain, snow, etc could not enter the box from the bottom. We also would put an approved drain fitting in the bottom of the box, for added protection incase water somehow got into the box. Experience pays.
Openings on the bottom of a PVC junction box, is a great idea. When I worked for DuPont at a chemical plant, we would always put the openings on the bottom of PVC boxes for our heat tracing, systems, which would cover hundreds of feet.
The reason for this is that rain, snow, etc could not enter the box from the bottom. We also would put an approved drain fitting in the bottom of the box, for added protection incase water somehow got into the box. Experience pays.
petersonra
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- Northern illinois
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- Semi-retired engineer
Re: PVC PULL BOXES
I though he was refering to the PVC boxes with the hubs on them already. he must be using something else then.
Re: PVC PULL BOXES
thats it. I noticed in Mike Holts Jan 05 significant proosals for the 2005 NEC, 9-5 312.2 that the Author's comment stated that this would include a Meyer's hub or sealing locknut. Would only a sealing locknut inside the box be sufficient. The specs for the project don't specify a NEMA rating for the boxes, so would a NEMA 3R rating be acceptable and do I even need a watertight connection on the bottom of the box where the PVC male adapter enters the box.
thats it. I noticed in Mike Holts Jan 05 significant proosals for the 2005 NEC, 9-5 312.2 that the Author's comment stated that this would include a Meyer's hub or sealing locknut. Would only a sealing locknut inside the box be sufficient. The specs for the project don't specify a NEMA rating for the boxes, so would a NEMA 3R rating be acceptable and do I even need a watertight connection on the bottom of the box where the PVC male adapter enters the box.
Re: PVC PULL BOXES
pageman
The enclosure you describe is a pull or J box (IMO) and where it is installed subject to weather I believe 314.15 is a more appropriate reference.
The raceways terminated at the bottom are generally considered to "not" be subjected to immersion in liquid or direct rain. see the definitions of raintight and wet locations. I would consider these raceways to be damp locations and the installation you described has been installed in many locations for a good while.
Unless the AHJ sees a different situation than described I think the installation is fine.
Charlie
[ March 01, 2005, 03:38 PM: Message edited by: cpal ]
pageman
The enclosure you describe is a pull or J box (IMO) and where it is installed subject to weather I believe 314.15 is a more appropriate reference.
The raceways terminated at the bottom are generally considered to "not" be subjected to immersion in liquid or direct rain. see the definitions of raintight and wet locations. I would consider these raceways to be damp locations and the installation you described has been installed in many locations for a good while.
Unless the AHJ sees a different situation than described I think the installation is fine.
Charlie
[ March 01, 2005, 03:38 PM: Message edited by: cpal ]
Re: PVC PULL BOXES
I think the inside of conduit "in a wet location" is a wet location. Thus, the wire has to be something like THWN. So I don't understand what the big fuss over the box being weatherproof is?
My opinion, is it is better than OK.
Steve
I think the inside of conduit "in a wet location" is a wet location. Thus, the wire has to be something like THWN. So I don't understand what the big fuss over the box being weatherproof is?
My opinion, is it is better than OK.
Steve
Re: PVC PULL BOXES
Pageman
Doing the voltage drop calculations and using a 3% VD you may want to go up to a larger conductor. My calculations say you should use at least a #6. I am sure if I am wrong someone will correct me. I used the full load current of 7.6 from 430.150 in my calculation. I am also looking at the fact every 200 feet you are making a splice. I know in a perfect world that will not matter but you are doing this in a wet location and no matter how hard you try there will be water in those boxes.
Pageman
Doing the voltage drop calculations and using a 3% VD you may want to go up to a larger conductor. My calculations say you should use at least a #6. I am sure if I am wrong someone will correct me. I used the full load current of 7.6 from 430.150 in my calculation. I am also looking at the fact every 200 feet you are making a splice. I know in a perfect world that will not matter but you are doing this in a wet location and no matter how hard you try there will be water in those boxes.
Re: PVC PULL BOXES
Thanks for the input so far, just to let you know the pull boxes are mounted on two pipes set in concrete and are amounted approxiamltey 12" above ground surface, Also the specs called for the max spacing of 200 feet on pull boxes. I have looked and looked for a listing of connections approved for wet conditions, can anyone point me to this NEC/UL approved list? Thanks again!
Thanks for the input so far, just to let you know the pull boxes are mounted on two pipes set in concrete and are amounted approxiamltey 12" above ground surface, Also the specs called for the max spacing of 200 feet on pull boxes. I have looked and looked for a listing of connections approved for wet conditions, can anyone point me to this NEC/UL approved list? Thanks again!
Re: PVC PULL BOXES
pageman,
NEC, nonmetalic ridged conduit,"uses permitted", wet locations ,next; Boxes and fittings, shall be listed fittings--as long as yuor boxes and fittings are listed then they are good for wet locations.
Also, you have installed your equipment as to prevent water from entering. this is all NEC
frank
pageman,
NEC, nonmetalic ridged conduit,"uses permitted", wet locations ,next; Boxes and fittings, shall be listed fittings--as long as yuor boxes and fittings are listed then they are good for wet locations.
Also, you have installed your equipment as to prevent water from entering. this is all NEC
frank
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