Electrical installations require a lot of components that each serve a particular purpose, and enclosures are an essential part of the equation. Now, these components may appear the same and may seem as though their services can be swapped for others but the truth is, they can’t. If not a bad idea, swapping one for the other may be catastrophic. That is why, you need to ensure that you work with the right team, that knows the differences and how to handle each specifically.
In this article, we are going to look at the major differences between a pull box and a junction box, the purpose they serve and how each is used significantly. Read on!
The term comes from the fact that pull boxes are used in conjunction with conduits to make wire installation easier. Made from household appliances mould, they are constructed of sheet metal, cast metal, or a non-metallic substance and they allow conductors to be pulled across long ranges without putting too much strain on the wire or insulation. Long wire runs may be placed at shorter intervals with pull boxes, which can be utilized for both straight and angled pulls.
Pull boxes do not contain wire connections inside, despite their similar appearance to junction boxes. Only conductors are pulled and fed into a raceway system through these locations. They must be used in conduit lines when the number of bends connecting outlets surpasses the National Electric Code’s maximum number.
The size of a pull box is determined by the size and amount of conductors, as well as the quantity and diameter of raceways. Pull boxes and junction boxes for conductors 4 AWG and greater must be sized in compliance with NEC article 314.28. We will include an explanation of the size guidelines for the most frequent sorts of pulls.
The conduit enters and exits the box on opposing sides in straight pulls. The size of the biggest conduit and the space required by locknuts and bushings define the depth of a box for a straight draw. The length of the draw box, on the other hand, must be at least eight times the biggest conduit’s radius windage.
Boxes and conduit bodies holding conductors 4 AWG or greater, as well as angle or U-pulls, must be sized according to NEC’s standards.
The length between each raceway entrance inside the box and the box’s opposing wall must equal the sum of the following for angle pulls:
When conductors enter and exit from the same wall, the distance between the raceways’ entry point and the opposing wall is computed using the same method as for angle turns:
It’s worth noting that each conductor’s entry and exit points are tallied individually.
When there are both straight and angle pulls in the same box, the calculations must be done using both sets of criteria, with the greatest dimensions being used.
A junction box is an electrical container that protects electrical wires at their splicing, tapping, and pulling points. These shields allow electricians to readily access the wires to do maintenance while also protecting them from harm and illegal access. The phrase “junction box” is also used to refer to an electrical fixture box. Wires in a junction box should only link to other wires and raceways, according to the correct technical definition. In reality, however, the word is often used to refer to a variety of various electrical box types that connect cables to a fixture such as a ceiling fan, light switch, or wall socket.
Metal or plastic materials are used to make the majority of boxes. The sort of material you employ will be determined by the task. If wires will be run via a metal conduit to a box, a metal box is used. That substance will aid in the grounding of the conduit and wires.
A metal or plastic junction box is used if the cable being used isn’t composed of metal. When connecting the connection to the box, a cable clamp is utilized. As a result, it’s safe.
Round pan boxes are shallower containers that are generally about 3-quarters inches deep maximum. For light fixtures or smaller things, most contractors install them in the ceiling or wall; the ideal use is for items weighing below 22.6 Kgs. Ceiling fans may be installed using specialized metal pan boxes, however, most models cannot withstand the excessive weight.
Depending on the size of the container, octagon and round boxes provide a bit more versatility. For light fixtures and ceiling fans weighing at 22.6 Kgs maximum, these boxes are often placed in ceilings or walls. Round or octagon boxes are ideal for installations that require additional wire space. Larger units can be used as junction boxes if necessary.
The sizing of a junction box differs from that of a pull box. In a junction box, you don’t need to calculate, but rather look through the guideline chat to estimate the minimum and maximum volume of the junction box, since It’s standardized.
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