Free tools
Work the systems, not the flashcards
Six free interactive tools for data center interview preparation. Walk the commissioning ladder and see who signs at each level, follow the power train from utility intake to the rack with the redundancy lens applied, and filter typical salary ranges by role with the source and date shown on every figure. Five practice drills cover the commissioning ladder, the power train, commissioning tags, inspection point types and permit selection.
What are these tools for?
They exist because the questions that decide a data center interview are structural, not factual. Nobody is really asking you to recite what a transfer switch is; they are asking whether you can follow a path, place a test at the right level, and say who signs the paper at the end. Reading that off a page is slow, so these let you click through the same diagrams our packs teach from and see the explanation attached to the part you picked. Each one is free, needs no account, and works without JavaScript, because the diagram and every explanation are in the page before any script runs. Where a tool touches material a paid pack covers in depth, it says so and links there rather than pretending to be the whole thing.
- Commissioning ladder explorer L0 to L6, what each rung proves, who signs it off, and a 9-item placement drill. Open the tool
- Power train explorer Utility to rack, box by box, with N, N+1 and 2N explained, then 8 symptoms to trace. Open the tool
- Salary explorer Filter and sort typical US ranges by role, with source and as-of on every row. Open the tool
- Tag drill 12 site findings. Tag each one, and see why the neighbouring tag would misread it. Open the tool
- ITP builder Hold, witness or review? Set the point type on 12 activities. Open the tool
- Permit picker 12 tasks, 17 permits. Name the one that governs, and what travels with it. Open the tool
Which one should you do first?
If your interview is for a commissioning or engineering role, start with the ladder, then the power train, and do the tag drill last, because the tags only make sense once you can place the work they describe. If it is a contractor, CSA or site-supervision role, start with the permit picker, then the ITP builder, and read the ladder afterwards so you know what the paperwork you are producing is feeding. If you are new to all of it, do the power train first: everything else on this page assumes you can follow a path from a source to a load.
When you want the worked answers, not just the reasoning
The drills give you the judgement. The packs give you the documents behind it: worked scripts, worked sheets, and the questions asked back to you with the answer structure printed underneath.