HSN Code and GST on Proximity Sensors: What Goes on the Purchase Order

If you are reading this, you are probably part way through raising a purchase order and the HSN field is blank. It is a small field that causes a surprising amount of trouble, because industrial proximity switches do not sit in one obvious place in the classification.

This page explains how the classification works, why two different headings are commonly used, and what to ask your supplier for so that your purchase order, your goods receipt and your supplier’s invoice all agree.

What HSN is, in one paragraph

HSN stands for Harmonised System of Nomenclature, the international product classification that India uses under GST. Every invoice line carries a code, and the GST rate follows from the code rather than from the product description. Get the code wrong and the rate can be wrong, which is a reconciliation problem later rather than an argument today.

Why proximity switches sit between two headings

The difficulty is genuine, and it comes from what the device actually does.

Argument one: it is a switch. A proximity switch has no display, no scale and no output you would read. It turns a circuit on and off without contact. On that reading it belongs with electrical switching apparatus in Chapter 85, alongside the limit switches it usually replaces.

Argument two: it is a measuring or detecting instrument. The device detects the presence of a target and reports it. On that reading it belongs with measuring and checking instruments in Chapter 90.

Both readings are defensible, which is why you will see proximity sensors invoiced under both chapters by different suppliers in India. Neither is automatically wrong, but they are not interchangeable on your books.

Where it genuinely changes

The classification is not purely a matter of opinion. It shifts with what the device is and does:

• A plain switching output with no measurement behind it points towards the switching apparatus reading.
• An analogue output that reports distance as a value rather than as on or off points towards the instrument reading, because the device is measuring rather than switching.
• A sensor supplied with an amplifier or control unit may be classified as a system rather than as the parts, which can change the answer again. This is common with NAMUR sensors and their control units.
• Imported goods are classified at the border, so the code on the bill of entry usually sets what follows.

The rate

The GST rate follows the heading, not the product name. Most industrial switching and sensing devices of this kind fall in the standard rate band rather than a concessional one, but you should confirm the applicable rate against the exact code your supplier uses rather than assuming it from a similar product. If your supplier cannot tell you the code they will invoice under, that is worth resolving before the order rather than after.

Nothing on this page is tax advice. Your finance team or your chartered accountant should confirm the classification for your own books, particularly if you are claiming input credit or importing.

The practical fix: ask for it on the quotation

Almost all of the trouble here comes from the code appearing for the first time on the invoice, after the purchase order has already been raised with something different or nothing at all. The fix is straightforward.

1. Ask your supplier to state the HSN code on the quotation, not only on the invoice. Then your purchase order carries the same code from the start.
2. Ask for it at line level if the order covers different device types. Sensors, control units and accessories may not share a code.
3. Keep it consistent across repeat orders. If a code changes between orders for the same part, ask why before you book it.
4. For imports, match it to the bill of entry. A mismatch between what was cleared and what was invoiced onward is the single most common cause of a query.

Ask us and we will put it in writing

We manufacture inductive, capacitive, photoelectric, magnetic and NAMUR proximity switches in Mumbai, and we supply Novotechnik and Contelec position sensors as authorised distributor for India and SAARC.

If you need the HSN code for a quotation, ask for it when you enquire and we will state it on the quotation itself, line by line, so that your purchase order and our invoice agree from the beginning. If you are reconciling an older order and need the code we used, send us the invoice number and we will confirm it.

For the rest of the buying decision, see our guide to what actually drives proximity sensor price in India.