Manufacturer BRD:

•https://www.hesselmann.de

•https://www.landisgyr.de

•www.suedkabel.de

•www.driescher.de

•http://www.nexans-power-accessories.com/

•www.pfisterer.com

•www.filoform.de/uebergangsmuffen-von-guertelkabel-3x1-leiter-kunststoffkabel

Manufacturer CH:

•https://www.otlm.eu

•https://new.abb.com/ch/distributiongrid/transformatoren

•http://www.splicetec.ch/

•www.bruggcables.com

•http://www.splicetec.ch/
Many documents with good pictures and explanations