Distribution section
IFS section
Service Section
This section always contains a main disconnect and usually also has utility and/or customer metering equipment.
The service section can be fed directly from the utility company’s transformer to serve as a service entrance. Service from the utility can enter the service section in a variety of ways. Cable can be brought into the switchboard from the top or bottom, giving additional application flexibility. You will need to work with the customer to determine what service entrance needs exist. This decision will affect the cost.
Figure 20. Bringing Service into the Service Section
Pull Section
The center example in Figure 20 shows the use of a Pull Section. The pull section is a common switchboard component. It is simply a blank enclosure containing empty space through which cables can be pulled
, hence the name.
A pull section is used most often with service entrance switchboards where the utility feed comes up through the floor. This allows the service section to be fed from the top without any exposed conductors.
The fourth example shows the use of a Pull Box, which is basically a top-mounted pull section. This is useful if there are extra connections to be made because it permits more space in which to work.
Distribution Section
Power moves from the service section to the distribution section. Here, it is divided and sent through branch circuit protection devices, then out to the branch circuits, to provide power to loads downstream.
In some applications, the size of the service section’s main disconnect device and associated bus requirements may necessitate the service section cabinet to be deeper than the distribution section cabinet. Because the rear of all cabinet sections are always aligned (for installation against a wall), the front of the service section cabinet will protrude. This is referred to as a Rear Alignment.
Figure 21. Front and Rear Alignment Vs. Rear Alignment
If the depth of the service section and distribution sections are the same, the switchboard installation has Front and Rear Alignment.
Some switchboards may require a deeper distribution cabinet for the circuit protection devices and bus. Or, extra depth may be added as an option. Again, work with the customer to understand the need. This decision may affect the cost.
IFS Section
An IFS section, or Integrated Facility Switchboard, may include panelboards, dry type transformers and blank back pans for mounting other equipment.
If panelboards and dry type distribution transformers are used within the same room as switchboards, it may make sense to consider IFS sections. IFS sections can reduce the need for lineal wall space required for equipment, thus reducing the area needed for equipment. Additionally, IFS can also significantly reduce the installation time while reducing the number of pieces of equipment for handling.
Spare, Provision and Blank Space
Customer specifications for protective devices will also affect cost. We have already covered the types of protection devices (switches and circuit breakers) commonly used in the switchboard. But there are some extra terms used in this area pertaining to the protective devices that you should know.
For future expandability, the customer could request a Spare protection device. This means that the protection device is bolted in place and connected to the bus. All the customer has to do is connect a branch conductor to it.
This is very different from ordering a provision. With this arrangement, a space is left in the panel for the future insertion of a protection device. The bus connectors are in place and ready to use when the customer is ready to expand.
Different still is the specification of a space. It is space on the panelboard/switchboard chassis that is simply covered with a blank panel. There is vertical bus in back of the panel, but a connector kit would be required to install a breaker in the future. The space can be defined for a defined overprotective device, in which can an appropriately sized filler cover will be supplied.
