Cable Gland for 2 vs. 4 vs. 6 Strings: Which one do I need?
When planning a PV system, a central question arises at the roof penetration point: How many cable openings do I need? NEXCAPE offers cable glands for 2, 4, and 6 PV strings — each with or without an earthing cable opening. This guide will help you choose.
Basic Principle: What is a String?
A string consists of several PV modules connected in series. Each string has two cables: positive and negative. A cable gland for "2 PV" therefore has two cable openings — suitable for one string (one positive and one negative cable).
| Variant | Cable Openings | Strings |
|---|---|---|
| 2 PV | 2 | 1 String |
| 4 PV | 4 | 2 Strings |
| 6 PV | 6 | 3 Strings |
When to Choose Which Variant?
2 PV — for small systems
The 2-PV variant is suitable for systems with a single string on one side of the roof. Typical for small private systems with 4-8 modules in series. Also ideal as an addition if an existing system is being expanded with a single string.
4 PV — the standard for detached houses
Two strings are the most common case for detached house systems. A 4-PV cable gland covers both strings via a single penetration point. This saves a second intervention in the roof surface and speeds up installation.
6 PV — for larger systems and commercial use
For systems with three strings per roof side — typically from 15-20 modules or for commercial installations — the 6-PV variant is the right choice. All six cables are routed through one penetration.
PE Variants: With Earthing Cable Opening
Each variant is also available as a PE version with an additional opening for the earthing cable:
- 2 PV+PE — 1 String + Earthing
- 4 PV+PE — 2 Strings + Earthing
- 6 PV+PE — 3 Strings + Earthing
The PE variant is recommended whenever there is no other cable path available for the earthing cable. For retrofits, the PE variant is almost always the right choice.
Planning Tip: Better to go one size larger
If it is foreseeable that the system might be expanded in the future, choose a cable gland with more openings than currently needed. Free openings can be temporarily sealed. This is significantly easier than adding a second penetration later.
Material and Availability
All variants are made of TPU (Thermoplastic Polyurethane), manufactured using 3D printing in Germany. Available in lengths of 105, 125 and 150 mm. Installation is tool-free — MC4 connectors do not need to be removed. B2B volume discounts from 20 pieces.
Find the right variant for your project: Roof penetrations for solar cables (105/125/150 mm)
