Grommet
The so-called grommet is used in electrical installations to seal the entry of cables and lines into electrical equipment against external influences such as foreign bodies and liquids.
Such nipples are initially closed bodies made of elastomer or elastic thermoplastic , which are inserted into round openings in the equipment ( switch cabinet , junction box , etc.). A cable is inserted by piercing the closed membrane. The cable is then enclosed on all sides by the elastic edge.
Grommet nipples do not provide strain relief and are therefore only suitable for permanent installations.
A corresponding standard for the sizes can be found in the area of the former standard for armored steel pipe threads and in the metric standard. The structural design of the grommet must meet the protection class of the electrical equipment. The swivel nipple was invented in 1956 by Günther Spelsberg GmbH + Co. KG in Schalksmühle / Westphalia and a patent has been applied for. Today, in addition to Spelsberg, a large number of manufacturers produce these accessories in a wide variety of designs.
The following pictures show unused double membrane seals.
Bottom view
Side view
Oblique view
Top view
See also
literature
- Hans-Günter Boy, Uwe Dunkhase: Electrical installation technology The master's examination . 12th edition, Vogel Buchverlag, Oldenburg and Würzburg, 2007, ISBN 978-3-8343-3079-6