How to Pulling Cable in Project site

2017-06-13

The Pulling of the cable have a very important relationship with the Drum design.So today I want to give some suggestions about how to pulling the cable in the project site.

When you want to pulling the cable in the outside below 5 points are very important.
First，Leave adequate clearance between the conduit and the cable.
Be sure there is adequate clearance between conduit and cable. Clearance means the space between uppermost cable in the conduit and the inner top of the conduit. Clearance should be 1/4 inch at minimum and up to 1 inch for large cable installations or installations involving numerous bends. 
Second You shall calculat the jam ratio
Jamming is the wedging of three cables lying side by side in a conduit. This usually occurs when cables are being pulled around bends or when cables twist.
The jam ratio is calculated by slightly modifying the ratio D/d. A value of 1.05D is used for the inner diameter of the conduit because bending a cylinder creates an oval cross-section in the bend.Especially for the steel armored cable . You shall calculated the right jam ratio.
Because there are manufacturing tolerances on cable, the actual overall diameter should be measured prior to computing the jam ratio.
Third Use the lubrication.
Use the lubricant more heavily at the beginning of the pull and less so towards the end of the pull, as the interior of the conduit will become coated along its length as you pull.
Please noted the above three points when pulling the cable in the outside. Anyway different kind of the cables has different property. Please be noted and use the right way to pull the cable and follow the manufacturer's instructions for proper application.For the bare conductor and steel armored cable ,you shall pay more attention on the instructions of the manufacturer.