Lessons · Lesson 4 of 6
Why it takes years to build
Some equipment takes longer to arrive than the building takes to build.
You cannot buy it off the shelf
The big electrical gear is built to order, and factories have long queues. The time from order to delivery is called the lead time.
The bars race to their typical lead time, in weeks, from published industry data.
Work backwards from the opening day
Planners pick the day they want to switch on, then count back each lead time plus time to install. Whatever has the least spare time is the critical path: if it slips, everything slips.
Move the opening date to see which items you would already be late to order.
Quick check
What is the “critical path”?
- The cheapest equipment
- The items with the least spare time, which set the earliest opening date
- The cable route from the grid
Show the answer
The items with the least spare time, which set the earliest opening date. If an item on the critical path is late, the whole project is late. Order those first.