Weidmüller offers an assortment of components for installing photovoltaic systems. For example, the WM4 connector was developed specifically for use in photovoltaic systems. The connector is made from the high-performance plastic PPE (polyphenylene ether, previously known as polyphenylene oxide PPO), which is processed to a blend.

The PPE blend utilized by Weidmüller is resistant to ammonia - a toxic gas that is created in particular as animal excreta decomposes. Agricultural farms are a powerful force driving the market for large area photovoltaic systems; however, ammonia gases on their roofs can attack the solar panels and connectors alike, and result in corrosion.

Weidmüller's accredited laboratory subjected the WM4 connector to a rigorously enhanced "corrosion-cracking test" in accordance with UL requirements (UL 486E). Both the plastic housing and the contact of the WM4 connector past the test with flying colours. Consequently, operators of PV systems installed in farms take no risk of experiencing corrosion caused by ammonia (NH3).