Step 00a.2 — Write the "who is in the room" rule and post it on the wall¶
Step 2 of 12 · Chapter 00a — Mains safety: read before Chapter 09
(no image — see text)
Parts: none.
Do: Write the mains carve-out to your daughter's measurement-log job, post it where you both see it, and say it out loud once before Ch 09.
Check
The rule is written, posted, and has been read aloud. Neither of you has to reconstruct it at 22:00 with the printer on its back.
What you're looking at
No parts: a written rule for the two people building this printer. It names the step ranges where only one person is at the machine, and what the other does instead, so the rule is decided in daylight rather than at the bench.
Step 00.30 gives her the measurement log, and that assignment has no carve-out for mains. The rule, in these words:
- She does not strip, land, tighten or unplug any conductor that is or has been connected to the wall.
- She is not in the room while the mains conductors are being worked on, or while the machine is plugged in with the bay open — Ch 10 Section 1 (10.1–10.16), the whole of Checkpoint #1 (10.17–10.23), and the firmware gate at 12.11 through Checkpoint 12, and the shut-down at 11.67. Those are adult-only.
- She is not beside the machine at any power-on — 10.23, 12.11 and 13.3. One adult, standing to the side, hand on the switch — nobody else within reach of the machine.
- What she does own on those days: the record, and only with the printer unplugged. In the post-power sweeps at 10.74–10.78, once 10.73 has read 0 V and the cord is out of the room, you hold the probes and read each value aloud, and she records it in the log. She never holds a probe. Recording every row is a real job: it is how you catch a row you skipped.
Caution
This rule is not about competence. It is about there being only one pair of hands near a live conductor, and about that pair belonging to the person who can also reach the breaker.
Source: Ch 00 Step 00.30 · Ch 10 Sections 1–2 · Ch 10 Section 8 · Ch 12 Step 12.11 · Ch 13 Step 13.3