Do Not Disconnect MC4 Connectors: Why This Is the Safer Solution
For many roof penetrations, MC4 plug connections must be disconnected to thread the cables through the opening. What sounds like a small step carries significant risks in practice — both for the safety and the performance of the PV system.
What Happens During Disconnection and Reconnection?
MC4 connectors are designed for a limited number of mating cycles. Each disconnection and reconnection increases the risk of:
- Contact problems: Contaminated or damaged contact surfaces increase contact resistance.
- Arcing: Poor connections can lead to dangerous arcing under load.
- Power loss: Increased resistance at the connection point reduces yield.
- Fire hazard: Faulty MC4 connections are one of the most common causes of fires in PV systems.
The Problem with Conventional Penetrations
Many cable penetrations on the market have openings dimensioned only for the cable itself — not for the much larger MC4 connector. This forces the installer to disconnect the plug connection, thread the cable through, and reconnect it on the other side. This process must be done twice per string (positive and negative), which multiplies the time required and the risk of error.
NEXCAPE: Passage for MC4 Connectors
NEXCAPE roof penetrations made of TPU (Thermoplastic Polyurethane) are deliberately designed so that MC4 plug connections can be installed completely assembled. The openings are large enough for the connectors — no disconnection is required.
This means:
- The factory plug connection remains intact.
- No risk from faulty reconnection.
- Time savings of 10-15 minutes per string.
- Higher system safety over the entire lifespan.
Safety-Relevant: Observe VDE Standards
VDE standards recommend not to disconnect MC4 connections if possible after mating. Every additional disconnection point is a potential point of failure. NEXCAPE penetrations constructively support this principle by making disconnection unnecessary.
Variants and Availability
The penetrations are available in variants for 2, 4, and 6 PV strings, each with or without a PE cable opening. The lengths 105, 125, and 150 mm cover common tile formats. Manufactured by 3D printing in Germany from UV-resistant TPU.
For installation companies, attractive B2B bulk discounts apply from 20 pieces.
Roof penetrations without MC4 removal — now in the NEXCAPE Shop: find suitable PV roof penetration
