Distance between MV cables Manholes

Status
Not open for further replies.
Sajid khan

Sajid khan

Senior Member
Location
Pakistan
Dear Forum Members,

What is the recommended distance between two manholes per NEC. I didn't find any recommended distance in NEC code.

In my case we have 8 Runs of 3x1C-630Sq.mm 13.8kV cables in duct bank. The designer proposed the distance between the manholes is
50 Meters. Is it Code compliant??

Thanks in advance.
 
What type of raceway is it?

For example, if PVC, 352.26 says no more than 360 degrees of total bends between pull points, but you also have to consider pulling tension and sidewall pressure calculations.
 
ron said:
What type of raceway is it?

For example, if PVC, 352.26 says no more than 360 degrees of total bends between pull points, but you also have to consider pulling tension and sidewall pressure calculations.
Click to expand...
PVC conduits encased in duct bank..

Sent from my GT-I9300I using Tapatalk
 
It is my opinion that the more times you have to handle the conductors, the more you risk damage to them. There is no reason why you need manholes every 50 meters for straight pulls. I often see them 125-150 m apart.
 
don_resqcapt19 said:
It is my opinion that the more times you have to handle the conductors, the more you risk damage to them. There is no reason why you need manholes every 50 meters for straight pulls. I often see them 125-150 m apart.
Click to expand...
Yes thats reasonable.. the runs are straight except at the two points i.e at source end and destination end and in between is the straight run..

My question is regarding the compliance with the code..

Sent from my GT-I9300I using Tapatalk
 
Sajid khan said:
Yes thats reasonable.. the runs are straight except at the two points i.e at source end and destination end and in between is the straight run..

My question is regarding the compliance with the code..

Sent from my GT-I9300I using Tapatalk
Click to expand...
There is nothing in the code other than the rule that says you cannot exceed 360° of bend between pull points. As others have said you do have to look at the pulling tension and sidewall pressure calculations to make sure the pulling force won't damage the conductors. Most often, the sidewall pressure and not the pulling tension is the limiting factor. The sidewall pressure can be reduced by using bends with a larger radius.
 
Sajid khan said:
Dear Forum Members,

What is the recommended distance between two manholes per NEC. I didn't find any recommended distance in NEC code.

In my case we have 8 Runs of 3x1C-630Sq.mm 13.8kV cables in duct bank. The designer proposed the distance between the manholes is
50 Meters. Is it Code compliant??

Thanks in advance.
Click to expand...
Who is the designer? :D
 
Status
Not open for further replies.
Top