CNS 61558-1: Taiwan’s BSMI Rolls Out New Standard for Battery Chargers and UPS Devices

Overview: Battery Charger and UPS Inspection

On September 8, 2026, Taiwan’s BSMI adopted CNS 61558-1, a new standard harmonized with international IEC 61558-1, replacing the prior domestic basis for testing battery chargers and related electrostatic converters. This conversion path is available for both the battery charger category and the UPS/switching power supply category: manufacturers already holding an IEC 61558-1 (2009 edition) type-test report can redo differential testing to convert it into a valid CNS 61558-1 report, avoiding a full retest. Alongside the standard update, BSMI also expanded which battery chargers require mandatory inspection in the first place.

CNS 61558-1 Coverage and Scope Expansion

CNS 61558-1 applies to two distinct product groups under BSMI’s mandatory inspection scheme:

1. Battery chargers — “other electrostatic converters” category
This category covers AC-to-DC power adapters. It does not include the steplessly adjustable DC power supply type, and it excludes medical devices and telecom terminal equipment. In simple terms, this is the general-purpose external adapter that plugs into a wall outlet and converts AC mains power to DC. For this category, CNS 61558-1 fully replaces the previous inspection standard. There is no alternative option. Manufacturers with an existing IEC 61558-1 (2009 edition) report can redo differential testing at the originally designated lab to convert it into a CNS 61558-1 report, rather than starting a full type test from scratch.

This is also where the scope expansion matters most. Non-3C (non-USB) chargers and DC-input chargers were previously outside mandatory inspection. They are now formally brought under CNS 61558-1 testing. This broadens the range of charger types manufacturers need to certify well beyond the standard USB-output charger.

2. UPS and switching power supplies — “other switching power supplies” category
This category covers switching-type AC-to-DC power adapters used with uninterruptible power supply systems and similar equipment. It excludes products designed for HI-END audio use, medical devices, and telecom terminal equipment. Here, CNS 61558-1 is offered as an alternative testing route, paired with a second new standard, CNS 61558-2-16. Manufacturers can choose this route or continue using the existing CNS 15598-1 pathway. The same conversion option applies here too: manufacturers holding an IEC 61558-1 (2009 edition) or IEC 61558-2-16 (2009 or 2013 edition) report can redo differential testing to convert it, instead of retesting from zero.

Unlike the battery charger category, this group is not affected by the non-3C or DC-input scope expansion. The only change here is the added testing option.

Most other standards in the announcement remain unchanged. These include CNS 15936, CNS 15598-1, CNS 13783-1, CNS 60335-1/2-29, CNS 13803, CNS 14757-2, and CNS 62040-1. RoHS labeling under CNS 15663 §5 also continues as before.

Supplementary Table: Affected Product Standards

Note: Excludes items classified as medical devices or telecom terminal equipment, per each category’s stated exclusions.

Note: Excludes items classified as medical devices or telecom terminal equipment, per each category’s stated exclusions.

Transition Timeline for CNS 61558-1 Compliance

• Now: BSMI accepts certification registration applications under CNS 61558-1.
• Existing certificates: Valid until expiry, unchanged models included.
• Through June 30, 2027: Renewals/extensions still allowed under the old standard.
• From July 1, 2027: All new applications, renewals, and the expanded charger scope require CNS 61558-1 compliance.

Key Takeaways

• CNS 61558-1 is the only newly adopted standard, replacing the AC-DC adapter basis and offering an alternative route for select UPS/switching supplies.
• The IEC 61558-1 (2009 ed.) differential-testing conversion path is available for both battery chargers and UPS/switching supplies — worth checking with clients before committing to fresh CNS 61558-1 testing.
• Non-3C and DC-input chargers are newly in scope. Clients making these should start planning now, not in 2027.
• Full CNS 61558-1 compliance is mandatory from July 1, 2027, giving roughly a 10-month runway from this announcement.
• The 14-working-day review period (plus 7 for sample testing) means early filing avoids a pre-deadline bottleneck.

Source

BSMI, Ministry of Economic Affairs, Taiwan — Announcement No. 11530016180, September 8, 2026.
https://www.bsmi.gov.tw/wSite/public/Attachment/f1789026150685.pdf