Understanding the Basics of Panel boards, Switchgears and Switchboards

All three types of gears, panelboards, switchboards and switchgears, have electrified aluminium or copper buses, and breakers attached to them. The wires connect the breakers with the electrical loads they are feeding. And, each type of gear has specific characteristics and varying preferences.

Panel boards

Panel board is a group of panel units which is designed for assembly in a single panel, or a single panel, including automatic overcurrent devices and buses. These are equipped without or with switches for controlling lights, power circuits, heat, etc. Panel boards are usually designed to be placed in a cut-out box or cabinet that is placed against or in the wall, or maybe partition, and are accessible from the front.

These can be commonly divided into panel boards and load centres.

Load centres are generally used in small commercial and residential applications. These are one of the least expensive methods of accommodating circuit breakers. In addition, usually, the breakers are also inexpensive as they are produced in great volume and can be simply plugged in the load centre bus.

Majorly, load centres are intended for applications up to 240V and are normally rated up to 225A. At such ratings, they are narrow enough to be fitted between the studs on 16″ centres and shallow enough to fit in a 2×4 stud wall.

However, panel boards are majorly used for up to 600V (voltages); nonetheless, even higher voltage ratings are available. Panel boards can even be rated up to 1200A. The smaller panel boards can accommodate bolt-on breakers or plug-in. However, large panel boards just utilize bolt-on breakers and are capable of having electronic trip breakers or standard thermal-magnetic trips with adjustable settings.

Panel boards are comparatively deeper than load centres. And, the panel boards that are rated 600A or higher are surface mounted on the wall and are deeper.

The choice of the type of panel board usually depends on:

• Voltage rating required
• Short circuit rating required
• Feeder devices’ Maximum current rating required

Switchboards

Switchboards are defined as a large and single frame, panel or assembly of a number of panels mounted on the back, face or both, overcurrent, switches, buses, and other protective devices. And these assemblies are usually accessible from the front as well as the rear as they are installed in cabinets.

Switchboards are somewhat similar to panel boards as they are usually rated for up to 600V; however, they might be able to handle higher fault currents than load centres and panel boards. Switchboards are floor mounted and are usually deeper than the panel boards.

As switchboards are larger in size and are quite expensive than the panel boards, their use is avoided for bus ratings which are less than 1200A. Both draw out breakers and bolt-on breakers can be installed in a switchboard line-up. In switchboards, mainly front access is required; however, side or rear access might also be required in some cases.

Switchgears

Switchgear is defined as an assembly that is enclosed completely on all sides and has a top with the metal sheet (except for inspection windows and ventilating openings). Switchgears contain interrupting devices, primary power circuit switching or both, with connections and buses. The assembly may even include auxiliary and control devices. And usually, access to the enclosure’s interior is offered by removable covers, doors or both.

Switchgear is even bigger in size in comparison to panel boards and switchboards.  Switchgears can have a rating up to 6000A and can be rated up to 38kV.

Normally, in switchgears, draw-out breakers are used, and access to the rear and front of the gear is required. And, switchgears are tested to a specific UL standard different from the panel boards and switchboards. As the breakers in switchgears are placed in different compartments, gears can be rated to withstand a short circuit for up to 30 cycles. However, on the other hand, switchboards and panel boards can withstand short circuit conditions only up to 3 cycles.

Switchgears often use draw out breakers, and these breakers can be easily detached from the bus for maintenance or replacement purposes without affecting other breakers or shutting down the main. Therefore, along with the moving parts, it is important to regularly maintain draw-out breakers, ensuring the mechanisms are properly lubricated and will function appropriately whenever required.

By now, you must have learnt about different sizes, load capacities and applications of panel boards, switchboards and switchgears. Therefore, depending on your industrial operations and other requirements, any of them could be a perfect fit. So, to make an appropriate choice, it is advisable to consult a professional before considering any of them for your application.

Sources:

https://en.wikipedia.org/wiki/Electric_switchboard

https://circuitglobe.com/switchgear.html