Cutting a light strip: which strips can be cut

First the question: where is the strip going and how long does it need to be?

Anyone who wants to cut a light strip usually has a specific measurement in mind: the underside of a kitchen cabinet, the back of a shelf, the edge of a bed or the wall behind the television. Before you reach for the scissors, some simple preparation is worthwhile. Measure the run twice, note the length and decide where the power supply and controller should sit. In almost all systems exactly this end is kept, while the surplus is cut away or, depending on the model, must not be separated at all.

The second piece of preparation concerns whether your strip is intended to be cut at all. That is not a given. There are strips with printed cut marks, where the manufacturer explicitly describes shortening at fixed intervals. There are strips where the manufacturer documents rule out cutting to size, because the electronics or the seal in the sheath are designed for the full length. And there are cases where documents from the same manufacturer contradict each other. The product pages of this editorial team state for each model what the sources provide, and this guide builds on exactly that.

This guide belongs to the smart lighting section. If you first want to clarify how much light a room needs overall and where a strip should be only an accent, the lighting calculator helps. In most homes a light strip is mood or accent lighting and does not replace task lighting. That also affects the length: a strip that only grazes a wall indirectly may be sized differently from one meant to light a work surface.

Note on the sources: we did not have any strip in hand and we have not measured anything. All information on the models mentioned comes from the manufacturer documents and listings evaluated on the respective product pages. There is no documented hands-on testing for any of the models. A classic Hue Lightstrip Plus with cut marks also has no product page of its own in this editorial team so far, so we name only models for which documents have been evaluated.

What happens technically when you cut

An LED strip consists of sections that each work electrically on their own. Between these sections there are copper contact pads intended as the cut point. If the strip is separated at these points, the rest of the strip stays functional, because the supply line and the control are connected at the other end. If it is cut in between, the conductor track is interrupted and everything beyond the cut point stays dark. Manufacturers usually describe it this way when they allow shortening at all.

For coloured strips with individually controllable segments there is a second layer. Such a strip carries a data line through which the controller assigns each section its colour. A cut then changes not only the length but also the number of segments the device expects. Whether a manufacturer allows this does not follow from a rule of thumb, but from the instructions for the respective model.

On weatherproof strips the sheath is part of the IP rating. An open cut would sever the seal. How IP ratings can be classified is explained in the guide on IP ratings. For outdoor strips the guideline is therefore: plan the length beforehand, do not adjust it afterwards.

Finally, a point that is often overlooked: the power consumption changes with the length. A shorter strip draws less power but also gives less total light. The power supply stays the same. That is not critical as long as the power supply was designed for the full length, and it explains why manufacturers limit extension beyond a maximum length.

Four strips compared: who allows cutting and who does not?

The following four models each have a product page of their own. They differ in exactly the point that matters for this topic: cutting to size. The information comes from the respective product pages; manufacturer values are given according to the manufacturer.

The table shows a clear pattern: only one model in this selection is explicitly intended to be cut. If you want to adapt a strip individually, the Paulmann set is the right choice. If you can lay a fixed run, the other models give you more room in control and place of use.

Cuttable according to the manufacturer: the Paulmann set

The Paulmann MaxLED 500 starter set 78885 is the model in this selection where cutting is part of the concept. According to the manufacturer, the cut points are every 100 millimetres, the set covers five metres with 60 LEDs per metre and can be extended to a maximum of eight metres using the plug system and connectors. Paulmann gives the colour temperature as 3000 kelvin and the IP rating as IP44; according to the manufacturer, Zigbee 3.0 is built into the strip. How kelvin figures affect the look of a room is explained in the guide on colour temperature in kelvin.

The operating restriction is important: Zigbee is a radio protocol and not a control unit. Without a hub, according to the documents the strip can be neither dimmed nor changed in colour. For control, Paulmann names the Zigbee remote Gent 2 and the smik gateway. As hubs from other manufacturers, the manufacturer page lists, among others, the Philips Hue Bridge 2 and Pro, with the exception of Hue Entertainment, as well as Amazon Echo with a Zigbee 3.0 interface. For use with a Hue Bridge, the Hue Bridge lamp limit is also relevant.

The product page also documents contradictions in the wattage figures: the listing title states 26 watts, while the manufacturer gives a fitted rating of 33 watts and a power consumption of 40 watts for the same item. If you are sizing the power supply or the extension lead, you should stick to the manufacturer's figures. The set fits if you use an existing Zigbee hub and want to adjust the length in steps of 100 millimetres.

Fixed length: Govee, Hue Outdoor and Hue Flux

For the Govee H618A RGBIC LED strip 5 m the situation is documented inconsistently. The supplied instructions explicitly prohibit cutting, whereas the European shop advertises the same series as cuttable. The product page follows the instructions, so you should plan with five metres in one piece. According to the product page the strip runs on 24 volts and 12 watts, connects via Wi-Fi and Bluetooth and is intended for coloured ambient lighting in dry indoor rooms. Govee gives no luminous flux figure in lumens for this model. It fits if you want to stick a fixed run behind a shelf, furniture or monitor and the measurement is right beforehand.

The Philips Hue Outdoor Lightstrip 5 m is weatherproof (IP67) and needs a Hue Bridge. According to the manufacturer pages, 1,650 lumens apply at 4000 kelvin and 1,500 lumens at 2700 kelvin, and the power is 37.5 watts. The manufacturer excludes cutting to size and extending in separate rows. Only the supply cable in the low-voltage system can be extended. For an outdoor strip with the Hue system this is therefore a model where you measure the run on the terrace, balcony or border edge in advance.

The Philips Hue Flux Outdoor Lightstrip 5 m is the alternative to a Hue outdoor strip if you do not want to require a bridge. According to the manufacturer it uses Bluetooth and Zigbee; a bridge is not mandatory, but extends the setup to up to 50 lights with 12 accessories. The length is 5000 millimetres, and the manufacturer's table explicitly says No for cutting to size and extending. The power is stated as 30 watts and 3,000 lumens at 6500 kelvin. The IP rating is IP67, and the power supply carries IP44. Check how far away the nearest covered outdoor socket is, because the cable cannot be extended at will.

Step by step: how to go about cutting

For a cuttable strip, in the example the Paulmann set, a simple procedure helps. It is a general guideline and does not replace the instructions for your model.

• Measure the run and allow a reserve for corners and the supply cable.
• Round the desired length to the nearest cut point, with Paulmann that is a multiple of 100 millimetres.
• Unroll the strip before sticking it and briefly connect it to the power supply so that you can see whether all sections light up.
• Unplug the power supply, only then cut, and do so at the cut point, not beyond it.
• Do not throw the offcut away straight away: on systems with extension it can serve as spare material.

Mains voltage at the power supply is not for DIY hands. If you are unsure about a 230 volt connection, consult a qualified electrician if in doubt. The strip itself works in the low-voltage range, whereas the power supply unit is connected to the socket.

If you have a strip that cannot be cut and are left with too much length, you have two clean ways out: lay the excess length behind the furniture in loops or waves, or choose a model that suits the run. Where cutting to size is prohibited, shortening is not a solution.

Extending instead of shortening, and the limits of the power supply

If the strip is too short, extending is the reverse route. This is not allowed everywhere either: for the Hue Outdoor and the Flux, the documents exclude extending. For the Paulmann set it is provided up to a maximum of eight metres, via the plug system that belongs to the system. Third-party connectors are not an alternative, because voltage, current and contact assignment must match the power supply.

With several lamps and strips in one Hue system, a second limit applies: the number of devices a bridge can manage. You will find details in the guide on the Hue Bridge lamp limit. For Paulmann's Zigbee system, according to the product page hubs such as the Hue Bridge are possible, with the stated restriction for Hue Entertainment.

As a general rule: plan the total length properly once before you order. The lighting calculator helps you sort the lighting tasks in a room and decide how much accent light you need at all. You will find further strips and controllers in the overview of smart lighting.