One of the best things about LED strip lights is that you can cut them to any length you need. But cutting and joining LED strips correctly can be tricky. Do it wrong, and you'll end up with dead sections or poor connections.

As an experienced LED strip light manufacturer, Arraystar LED has seen every possible mistake. This guide will teach you how to cut and join LED strips correctly.

Before You Cut: Important Rules

Rule 1: Only Cut at the Marked Lines

• Every LED strip has cut line markings (usually every 3-5 LEDs)

• Never cut between the marked points — you'll break the circuit

• Look for the line with copper solder pads (+/−)

Rule 2: Check Polarity

• LED strips have + (positive) and − (negative) markings

• When joining, + must connect to +, − to −

• Reversed polarity = dead strip

Rule 3: Measure Twice, Cut Once

• Measure carefully before cutting

• It's better to cut a little long and trim later

• You can't add length back once it's cut

How to Cut LED Strip Lights

Tools you'll need: Sharp scissors or utility knife, tape measure, marker

Step-by-step:

1. Measure the required length

2. Find the nearest cut line (don't cut past it)

3. Mark the cut line with a marker

4. Cut straight across the line with scissors or knife

5. Inspect the cut ends — make sure solder pads are clean

How to Join LED Strip Lights

There are two ways to join LED strips:

Method 1: Using Connectors (Easiest)

What you need: LED strip connectors (matching your strip width)

Steps:

1. Open the connector — flip the clear cover up

2. Insert the strip end — make sure +/− matches

3. Close the cover — press down firmly

4. Test the connection — power on and check

Pros: Fast, no tools needed, removable
Cons: Can be less reliable, bulkier

Method 2: Soldering (More Permanent)

What you need: Soldering iron, solder, wire strippers, heat shrink tubing

Steps:

1. Tin the solder pads on both strip ends

2. Tin the wire ends

3. Solder wires between strips — + to +, − to −

4. Insulate with heat shrink — slide over and heat

5. Test the connection

Pros: More reliable, cleaner, smaller
Cons: Requires soldering skills

Joining Around Corners

• L-shaped connectors — perfect for 90° corners

• Wire jumpers — use short wires to jump around corners

• Flex the strip — if flexible enough (like COB), you can bend it

Common Problems & Fixes

• Strip won't light up after joining: Wrong polarity (+/− reversed) — reverse the connection

• Dim lights at the joint: Poor connection, high resistance — re-solder or replace connector

• Lights flicker at the joint: Loose connection — re-seat the connector or re-solder

• Waterproof strip lost waterproofing: Cut broke the silicone coating — re-seal with silicone glue

Tips for Better Connections

1. Clean the solder pads — wipe with alcohol before connecting

2. Use the right connectors — match your strip width (8mm, 10mm, etc.)

3. Don't over-bend — stress at joints causes failures

4. Test before installing — fix problems while it's easy

5. Use heat shrink — especially for waterproof strips

Get Quality LED Strips & Accessories

At Arraystar LED, we supply everything you need for LED strip installation:

LED strips:

• COB LED strips (flexible, easy to bend)

• SMD LED strips (reliable, affordable)

• LED neon flex (curved lighting)

Accessories:

• LED strip connectors (all types)

• Aluminum channels & diffusers

• Power supplies & controllers

• Mounting clips & screws

📧 Email: info@arraystarled.com
📱 WhatsApp: +86 158 1851 4077
🌐 Website: www.arraystarled.com

Free samples available — test quality before you buy.