Step 00a.8 — Ferrules and the no-whisker rule¶
Step 8 of 12 · Chapter 00a — Mains safety: read before Chapter 09
Parts: none.
Do: Learn which terminal takes which, from the two rows below. Screw terminals get a crimped VE0508 ferrule; WAGO 221 lever terminals take bare stranded or ferruled core to the stop, with no copper visible outside any port.
Check
Ferrules found in the kit before Ch 10 starts, and you know which terminals take one, which take bare core, and the pull-and-look test.
What you're looking at
Two kinds of mains terminal. The PSU's three screw terminals each take a stranded core crimped into a red ferrule, a sleeve that turns loose strands into one tube the screw can clamp. The orange WAGO 221 lever blocks need no ferrule.
Two kinds of terminal carry mains in this machine and they want opposite things. Screw terminals — the Meanwell's L/N/⏚ block, L, N, ⏚ from the outer end, and the SSR's LOAD 1 / LOAD 2 — clamp a stranded core against a metal plate; strands splay, one escapes the clamp, and you are left with a reduced contact area that heats. The kit ships VE0508 ferrules for exactly this, five of them counted in Ch 09's hardware table and used in Ch 10. WAGO 221 lever terminals — the three 5-way N / L / PE blocks — clamp the core themselves; the failure there is not splaying but escaping, and 10.8 gives the test: tug each core hard, and confirm no copper is visible outside any port. A whisker of exposed strand next to a live terminal is the failure mode.
On conductor size, Voron's electrical page sets the floor: "Use at least 18 AWG (0.75 mm²) for mains AC wiring, even better would be 16 AWG (1.25 mm²)." Every mains conductor in this kit arrives pre-made; the number matters if you ever lengthen or replace one.
- Screw terminals (the PSU's L / N / ⏚ block, the SSR's LOAD 1 / LOAD 2): a crimped VE0508 ferrule on every stranded core, so no strand escapes the clamp.
- WAGO 221 levers (the three 5-way N / L / PE blocks): core to the stop, lever shut, then tug each core hard and look: no copper outside any port (10.8).
Caution
No whiskers. A strand of exposed copper beside a live terminal is the failure mode: if one shows, re-terminate that core. Mains conductors are at least 18 AWG (0.75 mm²); every one in this kit arrives pre-made, so this matters only if you lengthen or replace one.
Source: Voron docs — Electrical Wiring · image: LDO S3_wago_PSU.jpg · Ch 09 — Hardware · Ch 10 Step 10.8, Step 10.9
