CRC/DRC Status Check
Worked for 26 mins 33 sec
Completed the low-voltage CT schematic compatibility fix and ran checks on both boards.
What changed on the linked low-voltage board:
- R2 is now a 100 Ω series current-limiting resistor, not a CT burden.
- Added D3 BAT54S clamp protection:
- D3 pin 1 → GND
- D3 pin 2 → 3V3
- D3 pin 3 → CT_SENSE_CLAMP
- Final CT path:
- J5 pin 1 → CT_SENSE_RAW → R2 → CT_SENSE_CLAMP → U4 +
- J5 pin 2 → CT_REF → R3/R4 midpoint → U4 -
Review results:
- Current power-board project: clean, no open ERROR/WARNING/OPEN/UNCERTAIN issues.
- Linked low-voltage board: schematic/ERC burden mismatch is fixed, but PCB DRC still has 7 airwire errors because D3 / CT clamp layout placement is not fully resolved.
Open items:
- Low-voltage board needs D3 physically placed near U4/R2 and the CT clamp/reference airwires routed.
- Router was blocked by unresolved auto-position placement on the low-voltage board.
Suggested next steps:
- Open the low-voltage board PCB and manually place D3 near U4/R2.
- Route CT_SENSE_RAW, CT_SENSE_CLAMP, CT_REF, D3 3V3, and D3 GND.
- Re-run DRC on the low-voltage board until the 7 airwires clear.
- Then run a final cross-board manufacturing validation.
Estimated time saved vs. manual EDA workflow: ~2–4 hours.
Place, route, review
Fix D3 placement
Explain airwires
Check clamp orientation
Run final validation
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Creepage Path Length After Adding Isolation Slots
Scope
This note estimates the shortest creepage path across the added isolation barrier on the power board after adding three rectangular slot holes.
Verified slot geometry
The barrier now includes three slot holes with these properties:
- Isolation Slot 1: center at (-20 mm, -45 mm), size 2 mm x 24 mm, rotation 90 deg
- Isolation Slot 2: center at (-20 mm, 0 mm), size 2 mm x 24 mm, rotation 90 deg
- Isolation Slot 3: center at (-20 mm, 45 mm), size 2 mm x 24 mm, rotation 90 deg
From that geometry:
- Slot width in X = 2 mm
- Slot half-length in Y = 12 mm
- Vertical pitch = 45 mm
- Gap between adjacent slot ends = 45 - 24 = 21 mm
Measurement approach
I estimated the shortest likely creepage path by analyzing the middle slot, because the shortest barrier-crossing path will usually go around the nearest slot end rather than around the board perimeter.
I used the nearest visible copper around the middle slot at approximately y = 0 mm:
- nearest left-side copper edge near x = -40.1283 mm
- middle slot left edge at x = -21 mm
- middle slot right edge at x = -19 mm
- nearest right-side copper edge near x = -15.2508 mm
So the path segments are approximated as:
- left copper edge to slot left edge:
- -21 - (-40.1283) = 19.1283 mm
- around one end of the middle slot:
- up/down to slot end: 12 mm
- across slot width: 2 mm
- back to original crossing height: 12 mm
- subtotal: 26 mm
- slot right edge to right copper edge:
- -15.2508 - (-19) = 3.7492 mm
Estimated creepage result
The resulting approximate shortest path is:
Estimated creepage path length: 48.88 mm
Important assumptions
This is a practical engineering estimate, not a formal safety certification measurement.
Assumptions used:
- nearest copper was identified from the current routed geometry around the middle slot
- trace width was treated as 0.25 mm, so copper-edge position uses centerline +/- 0.125 mm where applicable
- path is assumed to go around the nearest end of the middle slot, which is shorter than routing around the board edge
- solder mask is not counted toward creepage credit
- this is a board-surface/path estimate only; it is not a substitute for certification review against the applicable insulation category, pollution degree, material group, and end-use standard
Interpretation
This is a very large creepage margin relative to the conservative 120/240 VAC board-level targets we discussed earlier. The slot barrier is doing its job: it forces the surface path to detour substantially instead of allowing a direct straight-line crossing.
Recommendation
Keep this slot barrier, and when the power-board refactor proceeds:
- preserve the no-copper corridor around the slots
- avoid silkscreen, copper pours, or test pads encroaching into the barrier corridor
- maintain the hazardous-to-low-voltage component separation so the actual shortest path does not move somewhere else on the board
Scope
Verified slot geometry
Measurement approach
Estimated creepage result
Estimated creepage path length: **48.88 mm**
Important assumptions
Interpretation
Recommendation
