The maximum length of an LED strip that can be installed in an LED profile primarily depends on the length of the profile itself. Most standard LED profiles come in lengths of 1 meter (about 3.3 feet) or 2 meters (about 6.6 feet), but some manufacturers may offer longer profiles or custom lengths.
However, it's important to note that the power source and voltage drop could also be limiting factors. For instance, if you're using a single power source for a very long LED strip, you may experience a voltage drop at the far end of the strip, which could make the lights dimmer there. To avoid this, you may need to provide power at multiple points along the strip or use a power supply with a higher voltage or current.
As always, you should follow the manufacturer's guidelines for the LED strip and power supply, and consider seeking advice from a professional electrician if you're unsure about the best setup for your needs.