In the case of AC and DC independently, the insulation resistance between the AC and DC parts of the high-voltage bus and the electrical chassis is required to be 500 ohms/volt and 100 ohms/volt respectively, and the test procedure is shown in Annex 2.

When AC and DC are connected to each other, choose one of the three:

1. The resistance between the high-voltage bus and the electrical chassis is 500 ohms per volt.

2. The resistance between the high-voltage bus and the electrical chassis is 100 ohms per volt, and there are at least two independent layers of solid-state insulation components, enclosures or barriers (such as cable sheaths) that meet IPXXD.

3. The resistance between the high-voltage bus and the electrical chassis is 100 ohms per volt, and it has sufficient durability to take into account mechanical protection (such as engine cover, electrical converter, connectors) throughout the vehicle use stage.

Charging port requirements: The insulation resistance of the high-voltage electrode of the charging port is 500 ohm/volt (AC) and 100 oh/volt (DC) when the charging is disconnected.

Annex 2 Insulation resistance value test process

As shown in the figure, to test the two-pole potential of the high-voltage bus, connect a resistor R0 with a known resistance value between the pole with a higher potential and the electrical chassis (generally take the neutral wire), here is an example of merging the positive electrode.

The insulation resistance value  , where  is the battery voltage,  is the positive voltage before the incorporation into the resistor, and  is the positive voltage after incorporating the resistor.

Waterproof requirements: Choose one of three requirements:

1. Manufacturers submit documentation and evidence to regulators and test sites that they can still meet the requirements of Annex 7A after wading through water
2. According to Annex 7B, the insulation resistance value requirements can still be met after wading through the water, and then another insulation resistance test is carried out 24 hours after that, and the requirements are still met
3. An insulation resistance detection system is installed and can give an alarm when the insulation resistance value is detected to be lower than the requirements, see Annex 6 for testing

Annex 6 Insulation Inspection

Connect a resistor R0 with a known resistance value between the pole with a lower potential and the electrical chassis (generally take the neutral wire), and change this resistance value, the alarm threshold is required to be within the following range:

The insulation resistance limit is 100 ohms/volt: 

The insulation resistance limit is 500 ohm/volt 

U is the working voltage of the electric drive.

Annex 7B water resistance test

Flushing: All edge lines (such as window edges, grilles, lamp edge lines, etc.) are subject to washing in all directions of the sprinkler water flow.

Wading: Passing through 10cm deep water at a speed of 20 km/h, with a total travel distance of 500m in the water, and completing the test within a maximum of 10 minutes

Rinse instructions:

Nozzle inner diameter: 6.3mm

Flow rate: 11.9-12.3 l/min

Water pressure: 30 kPa

Time per square meter of vehicle surface exposed to water stream: 1 minute

The minimum time for testing is 3 minutes

The distance from the nozzle to the vehicle is 3 meters, allowing for smaller

Battery Requirements:

BEVs should have low battery alerts

Every time the vehicle enters the drivable state, it should be prompted (usually a gear reminder), and this reminder is not mandatory for diesel locomotives.

When the driver leaves the vehicle, if the vehicle is still in a startable state, an alarm should be given

When the vehicle is charging (plug-in vehicle), the vehicle must not be able to drive, such as not being able to engage the gear.

Alerts are given when the battery temperature is abnormal