Plant up-time is critical. The unpredictability of an aging electrical system, coupled with the wear and tear of industrial equipment, creates “hiccups” in normal facility operation that can cause plant and maintenance managers to lose sleep, even on a good day.
One way to improve a plant’s resilience against unpredictable downtime is to design flexibility into its electrical system. This approach strategically adds additional infrastructure to the electrical system to provide options for recovery when an issue arises. Here are some ideas on how to build flexibility into an electrical system:
(1) Spare Conduits
Install spare conduits in duct banks or conduit racks when installing the project. This allows a failed feeder or wire to be disconnected and a new wire quickly re-pulled in an emergency.
(2) Tray System
Consider using a tray system for power distribution in lieu of conduits. It can be easier to add or change circuits in a tray system vs. in conduit, but there is added risk of a failure of one circuit also impacting others in the tray.
(3) Spare Breakers
Include 20-40% spare breakers when purchasing panelboards or switchboards. This provides backup breakers if one were to fail and allows flexibility for plant changes or additions.
(4) Spare Starters
Include 10-20% spare starters when purchasing motor control centers. This provides backup starters if one were to fail and allows flexibility for plant changes or additions.
(5) Wire Termination Points
Add additional wire termination points to critical infrastructure. For example, an extra set of lugs on a critical panel allows temporary connection of a generator during downtime without needing to disturb the permanent wiring. This speeds up the transition process out of shutdown and reduces risk as the permanent wiring is not altered.
(6) Electrical Areas
Lay out electrical areas to allow for expansion of equipment. Specify in the directions where new pieces of equipment could be added to the original lineup.
(7) Backup Generator / Automatic Transfer Switch
Install a backup generator and automatic transfer switch to maintain power to critical loads during a power outage. Maintain physical separation of this electrical system from other systems in the facility.
These options do come at a cost, but many are quite inexpensive to install up-front as compared to the cost of adding them when the facility is operating. It is recommended to review these options with the project team when planning for electrical improvements. With multiple viewpoints, the team can determine the most cost-effective way to add this flexibility while maintaining appropriate cost to the project.
If you’re interested in learning more about installed electrical flexibility, contact us at 712.722.1662.
Sam Fopma, Interstates Senior Project Engineer