Electrical Pull Box Sizing Calculator

Device boxes pull and junction boxes sizing of junction and pull boxes according to nec section 314 28.

Electrical pull box sizing calculator.

Three types of pulling schemes are used. This month the discussion continues with pull and junction box calculations. Straight pulls which travel straight through a pull box. 314 28 a minimum size pull and junction boxes.

This is an inefficient and expensive way to do an electrical installation. Then after the boxes are replaced the defective conductors are replaced. Boxes containing conductors of 4 awg or larger under 600v are calculated from the sizes and numbers of raceways see figure 1. And u pulls which turn 180 degrees to re enter the.

Conductor damage during installation is one consequence of under sizing junction and pull boxes. The national electrical code nec mandates specific sizes for pull boxes determined primarily by the conduit or raceway sizes and pulling scheme. Construction monkey has the perfect calculator for you. This damage is often not apparent until post installation cable testing.

You can review the following articles in the same course for more information. Angle pulls which make a 90 degree angle. When determining the minimum size box for conductors 18 awg through 6 awg the sizes and numbers of conductors are needed to calculate the minimum size box. Before the 1999 edition of the nec splices were not a factor when sizing pull and junction boxes.

Just answer the questions below and we will do the box fill calculations for you based on article 314 16 of the national electrical code. The sizing requirements for pull boxes junction boxes handhole enclosures and conduit bodies exist to prevent conductor insulation damage. Those requirements are in 314 28 and they apply to all conductors 4 awg and larger fig. 1 to illustrate how these requirements prevent conductor insulation damage let s consider two extremes in a straight pull situation.

Pull box sizing is based on the size and number of conductors as well as the number of raceways and their diameter. Today i will explain electrical boxes volume and fill calculations as follows. Do you need to calculate a box size given the wires that are going into the box. Last month s column discussed boxes containing both straight and angle pulls together in one box.

In article electrical boxes part two i explained the following items. Calculating the correct size of pull box needed can be complicated so please feel free to contact us or call 800 767 1576 if you need assistance.