Documentation
On high-voltage work, the paperwork is part of the safety system.
By Anthony LimpertASE Master Automobile Technician- HV work documentation supports safety, warranty, and liability. Detailed procedures protect the shop and technician if incidents occur later.
A complete HV work order proves the job was done to standard — and if something goes wrong months later, it is the record that protects the technician and the shop.
What Belongs on an HV Work Order
An HV work order needs far more than parts and labor. At minimum it should record the de-energization procedure followed, the verification voltage measured (and that zero volts was confirmed before work began), the PPE used, the torque values applied to HV connections, and the post-service verification results, including the isolation test outcome before re-energizing.
The reasons are safety, warranty, and liability all at once. Detailed documentation proves the shop followed the OE procedure, supports any warranty claim on the repair, and is the technician's defense if an incident occurs later — an isolation fault, a thermal event, an injury. 'We always do it right' carries no weight afterward; a work order showing the disconnect was pulled, the wait time observed, 0V verified with a CAT-rated meter, connections torqued to spec, and isolation tested at completion carries all of it.
- Record the de-energization procedure followed and the verification voltage measured — including that zero volts was confirmed with a CAT-rated meter before work began. This is the line that proves the job started safely.
- Log the PPE used with glove class and current test date. An incident review will ask; the record answers.
- Write down torque values as you apply them to HV connections, not from memory afterward. Both under- and over-torque are dangerous, and the recorded values are your proof of spec.
- Record the post-service isolation test result before re-energization. This reading is the evidence the vehicle left with its isolation barrier intact.
- Close with Ready-mode verification and archive the whole record with the RO. Months later, this document is the difference between 'we always do it right' and proof.
- Reconstructing the record at the desk after the job. Values written from memory are estimates wearing the costume of data — record at the fender, as each step happens.
- Omitting glove class and test dates. PPE that cannot be shown to have been in certification is PPE that legally was not worn.
- Skipping the isolation reading because the monitor was happy. The stored numeric reading is what defends the shop if an isolation fault appears later — 'no light came on' defends nothing.
Six months after an HV repair, the vehicle has an isolation fault and the owner blames the shop. What in your documentation decides how this goes?
The recorded post-service isolation test reading. A documented passing measurement at delivery proves the barrier was intact when the car left, pointing the new fault at subsequent damage or wear. Without that recorded number, the shop is arguing memory against an incident — which is exactly the situation the work order exists to prevent.
Why record the verification voltage as a number instead of checking a 'verified de-energized' box?
A number carries evidence a checkbox cannot: it shows a measurement actually happened, at designated points, with a real result. Checkboxes get ticked from habit; a recorded 0.0V with meter and date is data. In safety documentation, the difference between attested and measured is the whole game.
Six months after an HV repair, the vehicle has an isolation fault and the owner blames the shop. What in your documentation decides how this goes?
Missed one? The reasoning above comes straight from the EVH exam bank, so this is the standard you will be held to.