What orange means
The colour is a convention and it is followed universally: orange cable, orange connectors and orange warning labels mark the high-voltage traction circuit. Depending on the vehicle that is somewhere between about 200 volts and 800 volts, and it is DC.
DC matters more than the number. Alternating current passes through zero a hundred times a second, and that is what lets a person let go. Direct current does not. A DC contact across the chest closes the hand around the conductor and holds it there.
There is no useful comparison to household wiring here. This is a different category of hazard and it is treated as one.
The sequence, and why every step is in it
1. Pull the service disconnect. Every electrified vehicle has one — a service plug, a service disconnect grip, or a manual disconnect. Removing it opens the pack's internal circuit roughly in the middle, so neither half can present full pack voltage.
2. Keep it on your person. Not on the bench, not on the wing, not in a pocket somebody else can reach. The only thing standing between the system and re-energisation is that plug being out, and the only way to guarantee it stays out is for it to be in your pocket.
3. Wait. The inverter's DC-link capacitors hold a charge after the pack is isolated. Manufacturers specify a wait — commonly five to ten minutes, sometimes longer. It is in the service information for the specific vehicle and it is not a guideline.
4. Measure. This is the step people skip and it is the step that matters. Confirm zero volts at the point you are about to touch, with a meter rated CAT III 1000 V or CAT IV, on a range that will read the full pack voltage. Test the meter on a known live source before and after, so you know it was working when it told you the circuit was dead.
Equipment that is actually rated
Class 0 insulating gloves. Rated to 1000 V, worn with leather protectors over them. Before every use they are inspected for cuts and air-tested by rolling the cuff to inflate them and listening. They also have a test date — in-service gloves are retested on a six-month cycle, and a glove past its date is not protective equipment, it is a glove.
Insulated tools to IEC 60900. Not tools with a plastic-dipped handle. A rated tool is tested at 10,000 V and marked with the double-triangle 1000 V symbol; a dipped handle is a grip.
A meter with the right category rating. CAT III or CAT IV. The category describes what the meter survives when something goes wrong upstream of it, not what it can display.
Working practice
- One hand where the job allows it. Keep the other out of the vehicle, so no path exists across the chest.
- Remove rings, watches and any metal jewellery. A ring is a low-resistance loop.
- Have a second person present who knows the vehicle is being worked on and where the disconnect is.
- Insulate what you are not working on. A rubber mat over adjacent conductors removes an accidental second contact point.
- Do not work on a vehicle that is charging, has been in a collision, or is showing an isolation fault, until the specific procedure for that condition has been read.
After a collision, and after a fire
A pack that has taken an impact is treated as damaged until proven otherwise, and several manufacturers require inspection of the pyrotechnic disconnect and the interlock loop before the vehicle is re-energised at all. Damaged cells can go into thermal runaway hours or days later, which is why a damaged EV is quarantined at a distance rather than parked in a workshop.
Where the line is
Everything above describes what the procedure is, not a qualification to carry it out. High-voltage work on a traction system is licensed technician work in most jurisdictions and it is the right rule.
What this guide is for is knowing which side of the line a job is on — so that a brake caliper, a wheel bearing or a cabin filter gets done without hesitation, and anything orange gets handed to somebody with the certification, the gloves in test and the manufacturer's procedure open in front of them.
Questions people ask
- Is 48 volts high voltage?
- Not by the safety classification — the threshold is 60 volts DC, and a 48-volt mild-hybrid system sits below it. It is still enough to weld a dropped spanner to a chassis rail and start a fire, so it gets disconnected properly, just not with the same protective equipment.
- Can I repair a damaged orange cable?
- No. High-voltage cable is shielded and terminated to a specification, and the shield is part of the system's isolation monitoring. It is replaced as an assembly. A spliced repair will either fail the isolation test or fail later, in a worse way.
- Do I need to do anything before working on brakes or suspension?
- Usually not — most chassis work does not go near the traction circuit. What changes is what you must not do: never lift or support the vehicle on the battery enclosure, and never drill, cut or weld anywhere near a pack or its cabling.