Four quarter turns

[patrox2000]

Hello everyone,

I know the NEC requires raceways to have a maximum of four quarter turn per single conduit run, but does this apply to conduits containing conductors above 600V? if not, what is the NEC rule for underground, over 600V direct buired or concrete encased conduits.

thanks.

 

[Dennis Alwon]

I have never seen anything that would change the number of bends in a conduit run. Obviously direct burial cable does not matter how many bends but you must follow art. 300.34 for the radius of the bend. Art. 300.50 is for underground installs specifically

 

[patrox2000]

How come it doesnt mater?

How come it doesnt mater?

Article 352 on PVC says PVC conduits is allowed for direct burial and concrete encasement and also limits the numbero quarter bends to four.

 

[celtic]

It doesn't matter for direct burial cables because you will not be pulling the cables through conduit.
If you should decide to pull the direct burial conductors through conduit, the max 360? applies - as it does to any conduit, regardless of conductor type pulled.

 

[Dennis Alwon]

Article 352 on PVC says PVC conduits is allowed for direct burial and concrete encasement and also limits the numbero quarter bends to four.

Direct burial cable is laid in the ground without conduit. If you are talking conduit in the ground then yes you are limited to 360?

 

[patrox2000]

Restating my question, does the four quarter turn rule apply to conduits containing conductors above 600V? if not, what is the NEC rule for underground direct buired conduits or concrete encased conduits containing conductors with voltages above 600V?

 

[Dennis Alwon]

The 360? bends allowed in conduit is also for 600V. It doesn't matter if the conduit is in the ground or above ground-- 360? max (4 quarter turns if you prefer)

 

[celtic]

Restating my question, does the four quarter turn rule apply to conduits containing conductors above 600V? if not, what is the NEC rule for underground direct buired conduits or concrete encased conduits containing conductors with voltages above 600V?

It applies to every conduit everywhere.

 

[patrox2000]

It applies to every conduit everywhere.

That's what i thought. thanks.

 

[celtic]

That's what i thought. thanks.

Don't you want to know "WHY?" ?

 

[jumper]

Don't you want to know "WHY?" ?

Yes.

 

[patrox2000]

Don't you want to know "WHY?" ?

Sure, please tell me.

 

[Dennis Alwon]

The number of bends is directly proportional to the amount of tension that is on the wires during a pull. If the system is installed and you have too many bends it would be difficult to install as well as harmful to the conductors. The probably of degrees in the bend is the same both above and below ground.

 

[celtic]

Section 3xx.26 limits the number of bends in one run to reduce pulling tension on conductors and helps ensure easy insertion or removal of conductors during later phases of construction, when the conduit may be permanently enclosed .

 

[patrox2000]

Section 3xx.26 limits the number of bends in one run to reduce pulling tension on conductors and helps ensure easy insertion or removal of conductors during later phases of construction, when the conduit may be permanently enclosed .

Thanks a lot for the information.