Underground wiring, Vaults, Pullboxes

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Fordean

Senior Member
Location
New Jersey
Occupation
Electrical Contractor
Running 2 - 2 inch conduits. Maybe able to run PVC, Would Prefer RGS since water tank. But specs says, optional.

Question is Run is 600 feet from Vavle box to Water tank. Hill and valley. What would be required (if required) Small vault or pullbox points. How many for 600 feet. And at what distance apart.
 

iwire

Moderator
Staff member
Location
Massachusetts
Unless there are more than 360 degrees of bends I would not put any pull boxes in.

I would stick with PVC, RGS will only rust away underground.
 

Julius Right

Senior Member
Occupation
Electrical Engineer Power Station Physical Design Retired
I am not sure I understood well your problem. First of all I think iwire idea to use pvc instead of GRS it is a very good idea. If you can afford to use embedded ducts instead of conduit-still 2? diameter is very small for pvc-will be better-along a road and at least 2 ft. deep I think. In this case-it depends on cable weight ?you need a manhole [or a handhole] all 120-150 ft. However it seems to me expensive. Nevertheless from the last manhole galvanized steel-or a water tight flexible conduit or both-has to be provided.
 

Fordean

Senior Member
Location
New Jersey
Occupation
Electrical Contractor
Explanation

Explanation

I am not sure I understood well your problem. First of all I think iwire idea to use pvc instead of GRS it is a very good idea. If you can afford to use embedded ducts instead of conduit-still 2? diameter is very small for pvc-will be better-along a road and at least 2 ft. deep I think. In this case-it depends on cable weight ?you need a manhole [or a handhole] all 120-150 ft. However it seems to me expensive. Nevertheless from the last manhole galvanized steel-or a water tight flexible conduit or both-has to be provided.

If you can explain Embedded ducts and last manhole, A little cleared would appreciate it.


We are trenching 600 feet , What is the Requirement of manholes or pullboxes? Is the a Mandatory spacing. Or can you do what ever you want. Can you trench 600 feet and pull without not handholes. ?

I will try to use PVC. Only runnin like # 3 thwn conductors. They spec #12 wires. But they do considered the Derating distance. So I anticipate # 3 for 600 feet.
 

steve66

Senior Member
Location
Illinois
Occupation
Engineer
If you can explain Embedded ducts and last manhole, A little cleared would appreciate it.


We are trenching 600 feet , What is the Requirement of manholes or pullboxes? Is the a Mandatory spacing. Or can you do what ever you want. Can you trench 600 feet and pull without not handholes. ?

I will try to use PVC. Only runnin like # 3 thwn conductors. They spec #12 wires. But they do considered the Derating distance. So I anticipate # 3 for 600 feet.

There is no limit on distance between pull boxes in the NEC. There is a limit on bends - 360 degrees which is 4 - 90 degree bends.

So if its a straight run, you don't need any pull boxes or handholes per code. However, you have to decide if you can pull the wire in without exceeding the maximum pull tension for the wire.

If you can state the wire size and type, and conduit size and type, some of the contractors here could probably tell you how hard a 600' pull would be.
 
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