UN R100 Supplement 6 (03 series) · UNECE Regulation No. 100 (ECE R100) — Uniform provisions concerning the approval of vehicles with regard to specific requirements for the electric power train.
UN R100 — Supplement 6 to the 03 series of amendments
Supplement 5 → 6
- What changed
- When the isolation resistance monitoring system detects an isolation resistance below the requirements, a category O trailer must warn the driver of the towing vehicle.
- The thermal propagation requirements of paragraph 6.15. do not apply to REESS solely installed on vehicles of category O.
- Paragraph 6.4.1.3. now says that Annex 5A applies after the vehicle based test and Annex 5B after the component based test.
- Why
- The proposal corrects inconsistencies that followed the amendment of this Regulation for vehicles of category O.
- The warning requirements of paragraph 5.1.4.4. should be aligned with the requirements of paragraph 5.2.3.
- The expert from the Kingdom of the Netherlands explained that the term REESS does not include batteries used for recuperation only.
Q1What changed6 changes
Warnings from category O trailers (paras. 5.1.4.4. and 5.2.3.)
If an isolation resistance monitoring system detects an isolation resistance less than the requirements of paragraph 5.1.3., a warning must be given to the driver. Paragraph 5.1.4.4. now adds that a trailer of category O must give an optical and/or audible warning to the driver of the towing vehicle. In addition, a trailer of category O3 or O4 may give the towing vehicle a signal for an optical and/or audible warning. An example is transmission through CAN-Bus according to ISO 11992-2. In paragraph 5.2.3., the paragraph with this option for the events of paragraphs 6.13. to 6.15. now starts with “In addition”.
Thermal propagation: REESS solely installed on vehicles of category O (paras. 5.2.3. and 6.15.)
A new paragraph in paragraph 6.15. says that its requirements do not apply to REESS that are solely installed on vehicles of category O. They also do not apply to batteries on vehicles of category O used for recuperation. A new last paragraph of paragraph 5.2.3. gives the same exemption for its warning requirements related to paragraph 6.15. Before, these paragraphs did not contain this exemption.
Annex for the isolation resistance measurement after each test (para. 6.4.1.3.)
For a high voltage REESS, the isolation resistance must be at least 100 Ω/Volt for the whole REESS. As an alternative, the Tested-Device must fulfil the protection degree IPXXB. The text now says which annex applies to which test. Annex 5A applies after the vehicle based test (paragraph 6.4.1.1.), and Annex 5B applies after the component based test (paragraph 6.4.1.2.). Before, the text said only “after the test in accordance with Annex 5A or Annex 5B”.
Q2Why it changed
- Proposed by
- Expert from France
- Working party
- GRSP, 78th session (December 2025)
Reasons
The proposal from France corrects inconsistencies that followed the amendment of this Regulation for vehicles of category O. It says that its modifications are the same as for supplement 1 to the 05 series of amendments, except for paragraph 6.15.
Sources (3)
“prepared by the experts from France to correct inconsistencies following the amendment of regulation 100 by vehicles of category O”
“The modifications introduced in this proposal are the same as for supplement 01 to the 05 series of amendments (ECE/TRANS/WP.29/GRSP/2025/37), except for the modifications in paragraph 6.15.”
“which aim to correct inconsistencies regarding vehicles of category O”
Paragraph 5.1.4.4. is amended to include provisions for vehicles of category O. Its warning requirements should be aligned with the requirements of paragraph 5.2.3.
Sources (2)
“Paragraph 5.1.4.4. is amended to include provisions related to vehicles of category O. The warning requirements of this paragraph should be aligned with the requirements of paragraph 5.2.3.”
“The modifications introduced in this proposal are the same as for supplement 01 to the 05 series of amendments (ECE/TRANS/WP.29/GRSP/2025/37), except for the modifications in paragraph 6.15.”
The signal from trailers of category O3 and O4 to the towing vehicle is not mandatory. It only applies in addition to the warning that the trailer of category O must give to the driver of the towing vehicle. The change clarifies this to avoid any misunderstanding.
Sources (3)
“Those specific indications are non-mandatory and only apply in addition to the following prescriptions for vehicles of category O”
“clarifies the prescriptions for vehicles of category O and avoid any misunderstanding”
“The modifications introduced in this proposal are the same as for supplement 01 to the 05 series of amendments (ECE/TRANS/WP.29/GRSP/2025/37), except for the modifications in paragraph 6.15.”
At GRSP, the expert from the Russian Federation asked why the text needs a distinction between REESS and batteries used for recuperation only. The expert from the Kingdom of the Netherlands explained that, by definition, a REESS provides electric energy for electrical propulsion. Therefore, the term does not include batteries used for recuperation only. The experts from France and the Russian Federation then revised the proposal to avoid misinterpretations.
Sources (3)
“The expert from the Russian Federation asked why a distinction between Rechargeable Electrical Energy Storage Systems (REESS) and batteries used for recuperation only was needed in the regulatory text.”
“by definition a REESS provides electric energy for electrical propulsion and therefore the term does not include batteries used for recuperation only”
“The experts from France and the Russian Federation worked together to produce a revision of the proposal that would avoid misinterpretations.”
Paragraph 6.4.1.3. is amended for clarification purposes.
Sources (2)
“Paragraph 6.4.1.3. has been amended for clarification purposes.”
“The modifications introduced in this proposal are the same as for supplement 01 to the 05 series of amendments (ECE/TRANS/WP.29/GRSP/2025/37), except for the modifications in paragraph 6.15.”
Document trail
- 2025-09ProposalECE/TRANS/WP.29/GRSP/2025/38Proposal by the expert from France
- —Amended in sessionGRSP-78-37-Rev.2Modifications to the proposal, adopted by GRSP
- —Working party adoptsECE/TRANS/WP.29/GRSP/78Session report, para. 26
- 2026-03Sent to WP.29ECE/TRANS/WP.29/2026/49Text that GRSP sent to WP.29 and AC.1
- 2026-06-24WP.29 adoptsECE/TRANS/WP.29/1192Adopted at the 199th session (session report, para. 103)
- PendingIn forceDate not yet known
Q3Who is affected
Vehicle manufacturer
- Make sure a category O trailer with isolation resistance monitoring warns the driver of the towing vehicle.
- For a trailer of category O3 or O4, decide if it also gives a warning signal to the towing vehicle.
- Use Annex 5A after the vehicle based test and Annex 5B after the component based test.
Component supplier
- If you measure the isolation resistance of a high voltage REESS after the component based test, use Annex 5B.
Technical service / Approval authority
- Check the warning of category O trailers to the driver of the towing vehicle (paragraph 5.1.4.4.).
- Check which annex was used for the isolation resistance after each test: Annex 5A or Annex 5B.
- Do not apply paragraph 6.15 to REESS that are solely installed on vehicles of category O.
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ⓘ This report gives advice only. It is not legal or type-approval advice.