Medium Voltage Junction Box Sizing

Last month s column discussed boxes containing both straight and angle pulls together in one box.

Medium voltage junction box sizing.

For example 15 kv switchgear maximum voltage rating is commonly applied at various actual voltages including. 314 28 a minimum size pull and junction boxes. Suitable as connection panel for medium voltage cables. This post will provide an overview of the sizing rules for the most common types of pulls along with a calculation example.

The sizing requirements for pull boxes junction boxes handhole enclosures and conduit bodies exist to prevent conductor insulation damage. 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. We designed the medium voltage junction box mvjb for branching in the power grid our mvjb facilitates safe easy and quick connection and disconnection of medium voltage cables with same or different sizes and cross sections up to 42 kv. Calculate current a select power.

Our cable junction box provides you with a safe connection between oil filled cable and polymer insulated cables compared to cast resin cable sleeve. This month the discussion continues with pull and junction box calculations. Medium voltage switchgear is classified by the maximum voltage it can service. 1 to illustrate how these requirements prevent conductor insulation damage let s consider two extremes in a straight pull situation.

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. In straight pulls conduit enters and leaves on opposite sides of the box. Before the 1999 edition of the nec splices were not a factor when sizing pull and junction boxes. How to calculate underground pull box sizing determining the size of underground pull and junction boxes to meet nec 314 16 code standards is required to prevent damage to conductor insulation.

What solution can be used for medium voltage connections in the power grid. For conductors 4 awg and larger pull boxes and junction boxes must be sized in accordance with nec article 314 28. Those requirements are in 314 28 and they apply to all conductors 4 awg and larger fig. Kv custom kv.

Boxes containing conductors of 4 awg or larger under 600v are calculated from the sizes and numbers of raceways see figure 1.