In partnership with
Write docs 4x faster. Without hating every second.
Nobody became a developer to write documentation. But the docs still need to get written — PRDs, README updates, architecture decisions, onboarding guides.
Wispr Flow lets you talk through it instead. Speak naturally about what the code does, how it works, and why you built it that way. Flow formats everything into clean, professional text you can paste into Notion, Confluence, or GitHub.
Used by engineering teams at OpenAI, Vercel, and Clay. 89% of messages sent with zero edits. Works system-wide on Mac, Windows, and iPhone.
Why Insulation Testing Is Critical for DC Solar
DC string cables run through environments hostile to cable insulation — UV exposure, rodent habitats, mechanical abrasion on roof edges, and thermal cycling every day. Insulation resistance testing (IR testing) with a megohmmeter detects deteriorating insulation before it fails completely, preventing ground faults, arc faults, and inverter damage.
Test Procedure for Solar DC Circuits
Isolate the inverter: Open the DC isolator and disconnect the inverter DC input — you will be applying test voltage to the inverter's terminals otherwise
Short the string: Short-circuit the positive and negative conductors of the string at the combiner box or at the array DC isolator (this tests both conductors together against earth simultaneously)
Apply test voltage: Use 500 V DC for systems up to 500 V DC; 1000 V DC for higher-voltage strings. Apply for a minimum of 1 minute to allow capacitive charging to stabilise
Record resistance: Read insulation resistance at 1 minute. Note if the reading is rising (good — capacitive stabilisation) or steady (acceptable) or falling (concerning — potential moisture ingress)
Acceptance Criteria
Condition | Minimum Acceptable Resistance |
|---|---|
New installation (new cables, dry conditions) | >10 MΩ per string (ideally >100 MΩ) |
Commissioned installation (operational) | >1 MΩ per string |
Wet or damp conditions (morning dew) | >100 kΩ — retest when dry before concluding fault |
Below 100 kΩ in dry conditions | Fault — locate and repair before commissioning |
Engr. Jason Morales — Founder, SolarEnergyPH
