Charger safety and testing

What "safe" means for a charger

A wall charger connects your phone to the mains: about 230 volts AC in India. Everything inside exists to turn that into a gentle 5 or 9 volts DC, and to keep the two sides apart for the life of the product. Safety rests on three layers.

1. Isolation. Between the mains side and the USB-C side sits a barrier of insulation, a safety-rated transformer and carefully spaced copper. Its job is to stop mains voltage reaching anything you can touch, even if one part fails. Engineers talk about creepage (the shortest path along a surface between two conductors) and clearance (the shortest path through air). Reinforced insulation is a single insulation system that gives the same protection as two independent layers. ⁶

2. Protection circuits. Good designs detect trouble and shut down before it becomes dangerous:

3. Materials and construction. Flame-retardant enclosure plastics, capacitors rated above their working voltage and temperature, and solid mechanical fixing of the pins all matter. Apple's 20W adapter, for example, carries a 1.25 A, 250 V input fuse. ⁷

The phone has its own protection too. USB Power Delivery (USB PD), the protocol your iPhone uses to agree a voltage with the charger, includes defined behaviour for voltage transitions and resets. A compliant charger and phone are designed to fail safe together. See how USB Power Delivery works.

The standards behind the marks

IEC 62368-1: the safety standard that replaced 60950-1

For years, IT power adapters were tested to IEC 60950-1, and audio/video equipment to IEC 60065. Both have been replaced by IEC 62368-1, a hazard-based standard. Instead of a checklist of construction rules, it identifies energy sources (electrical, thermal, fire and more), classifies how hazardous each is, and requires safeguards between each hazardous source and the user. In the European Union, conformity to IEC 62368-1 became the requirement from 20 December 2020. ⁸

Apple states that the USB adapters it ships with iPhone and iPad are certified to IEC/UL 60950-1 and IEC 62368-1. It also says devices can be charged with "third-party adapters that comply with applicable safety standards". ⁹ That second sentence is the right test for any charger, Apple's or anyone else's.

India: the BIS Compulsory Registration Scheme

In India, safety testing is mandatory, not voluntary. Under the Electronics and IT Goods (Requirements for Compulsory Registration) Order, "Power adapters for IT equipment" must be registered with BIS against IS 13252 (Part 1), the Indian standard aligned with IEC 60950-1. ¹ The steps:

1. The manufacturer has samples tested at a BIS-recognised laboratory.
2. BIS grants a registration with an R-number.
3. The registration is valid for two years and must be renewed. ⁴
4. The Standard Mark with the R-number must be shown on the product or its packaging. ⁴

A change is under way. MeitY notification S.O. 4997(E) of 4 November 2025 replaces IS 13252 (Part 1) and IS 616 with IS/IEC 62368-1:2023. Old and new standards run side by side until 1 November 2028. After that, only IS/IEC 62368-1:2023 is accepted. ¹⁰¹¹¹² A charger registered today under IS 13252 (Part 1) is compliant; the transition date matters for its renewals.

Series registration: why the model number matters

BIS allows a manufacturer to register a series of closely related models under one R-number. Under the 2026 guidelines for IS/IEC 62368-1:2023, a series can hold up to ten models: one lead model and nine series models. They must share output ratings, number of outputs, enclosure (minor aesthetic changes only), construction class, safeguards and input voltage. The lead model is the worst case, and that is the one tested. ² Earlier guidelines for adaptors followed the same logic: one sample tested per ten models, the worst-case configuration. ⁵

So an R-number proves that a registration exists. It proves your charger is covered only if your charger's model number is on that registration's list.

Check any charger's BIS registration — step by step

You need: the charger (or its box), a smartphone, and about two minutes.

Step 1 — Find the Standard Mark. Look on the charger's casing (often moulded or printed on the underside or beside the pins) and on the box. You are looking for the BIS Standard Mark with a number in the format R-XXXXXXXX: the letter R and eight digits. ⁴

Step 2 — Note the model number. On the same label, find the model number. It is usually a code, not the marketing name. Write both down exactly.

Step 3 — Install BIS CARE. BIS CARE is the official Bureau of Indian Standards app, available on Android and iOS. ³

Step 4 — Open "Verify R-No under CRS". Enter the eight digits of the R-number, or scan the QR code if your document has one. ³

Step 5 — Read the result. The app shows the registered manufacturer, the product category and the standard. For a phone charger, the category should be a power adapter for IT equipment, and the standard IS 13252 (Part 1) or IS/IEC 62368-1:2023. ¹¹⁰

Step 6 — Match the model. Open the registration's model details and confirm your charger's exact model number is listed. If the app does not show the model list, use the "Registered Manufacturer under CRS" search by product category and model, or the registered-product search on crsbis.in. ³

Step 7 — Check validity. Registrations last two years. Confirm the registration is current. ⁴

What the result means

A note on what registration does not tell you. Registration confirms the model met the Indian safety standard when its lead model was tested. It does not grade quality above that floor, measure efficiency, or tell you whether the unit in your hand is genuine. For those, look for published test data and the brand's own authenticity check.

What a safety laboratory actually tests

A safety test house works through the standard clause by clause. For an adapter, typical checks include:

• Dielectric strength (hi-pot): a high test voltage is applied between the mains side and the output side for a set time. The insulation must not break down.
• Creepage and clearance measurement: distances between mains-side and output-side conductors are measured against the minimums the standard sets for the working voltage and insulation class.
• Abnormal and fault conditions: components are deliberately shorted or opened to confirm the charger fails safely.
• Temperature rise: the charger runs at full load until temperatures settle. Internal components and touchable surfaces are measured against the standard's limits.
• Output overload and short circuit: the output is overloaded and shorted to check that protection operates.
• Materials: enclosure flammability and mechanical strength, including pin and drop tests.
• Marking: the label must carry required ratings and warnings.

We describe these tests without quoting limit values here because the exact figures depend on the standard edition, insulation class and material.

Electromagnetic compatibility (EMC) is a separate discipline. It checks that the charger does not emit interference beyond set limits and keeps working when exposed to it.

Three marks people confuse: BIS, USB-IF and MFi

The practical result: a charger can be BIS-registered without USB-IF certification, and vice versa. Neither has anything to do with MFi. Any brand claiming "Apple-certified" for a USB-C wall adapter is claiming something Apple's programmes do not offer. Apple says it "does not recommend or endorse" third-party products. ¹⁴

Counterfeits are the real risk, not third-party brands

The genuine safety problem in India is counterfeit and unregistered chargers, not compliant products from other brands. Police have seized fake Apple accessories in Mumbai (goods worth ₹16.33 lakh) ¹⁵ and Kochi ¹⁶. A UK Trading Standards investigation reported by ScienceAlert in 2016 found that more than 99% of counterfeit iPhone chargers it tested failed a basic safety test. ¹⁷ That study is old and from another market, but the pattern is consistent: counterfeits cut out insulation, spacing and protection to save cost.

How to protect yourself:

1. Check the R-number and model using the steps above.
2. Be wary of prices far below the known MRP. Apple's 20W adapter is ₹2,190 MRP on apple.com/in ¹⁸. An "original" at a fraction of that deserves scrutiny.
3. Buy from the brand or its authorised retailers.
4. Use the brand's authenticity check where one exists.

Myths

"Only Apple's charger is safe for iPhone." Apple itself says third-party adapters that comply with applicable safety standards can be used. ⁹ Compliance is the test, not the logo.

"BIS-certified means Apple-approved." BIS registration is an Indian legal safety requirement. It says nothing about Apple. Apple does not approve third-party USB-C adapters.

"A hot charger is a faulty charger." Chargers get warm under load. Independent testing measured the back of Apple's 20W adapter at 49.5 °C after an hour at 20 W in a 25 °C room. ¹⁹ Persistent heat with no load connected, a burning smell, discolouration or a loose case are reasons to stop using it.

"The R-number on the box proves my charger was tested." Only if your model is on that registration's list. ²

Frequently asked questions

Is BIS registration mandatory for phone chargers in India? Yes. Power adapters for IT equipment are on the Compulsory Registration Scheme list under IS 13252 (Part 1). ¹ They may not be sold without registration and the Standard Mark.

Which standard will chargers move to? IS/IEC 62368-1:2023. It runs in parallel with IS 13252 (Part 1) until 1 November 2028, after which only the new standard is accepted. ¹⁰¹¹

A seller says "BIS certified" but shows no number. Should I worry? Ask for the R-number and model, then check them in BIS CARE. A claim you cannot verify is not evidence.

Does a USB-C charger need MFi certification to be safe with iPhone? No. MFi is Apple's licensing programme for accessories that use its connectors and protocols. A USB-C wall adapter delivers power over the open USB PD standard and does not need MFi.

Is USB-IF certification the same as safety certification? No. USB-IF certifies compliance with USB specifications. Electrical safety in India is covered by BIS registration. ¹³¹

What protections should a good charger have? At minimum: over-voltage, over-current, short-circuit and over-temperature protection, plus an input fuse. Ask the brand which protections a laboratory has verified, not just which are printed on the box.

Comparative caveats

This page names Apple only to quote Apple's own published safety statement and measured third-party data with attribution. It makes no claim that any product is safer than another. Comparative safety claims require like-for-like laboratory evidence and legal review.