Grommets

Cable grommets are rubber or PVC rings fitted into holes in metal and plastic so cables passing through are protected from sharp edges and abrasion. We stock 20mm PVC open grommets, 20mm closed grommets in packs of 100 and 25mm open grommets in packs of 50.

For irregular cut-outs there is a Unicrimp 5mm x 8mm grommet strip edge roll in 10m lengths. Open grommets let cable straight through, while closed versions seal unused holes until needed. Trade pricing is available on account, and orders for stock items placed by 5pm are delivered next working day across NI and ROI.

QGT10B In-Stock

Unicrimp 5mm x 8mm x 10m Grommet Strip Edge Roll

£10.56 inc. VAT

QGROM25OPEN 25mm Open Grommet by Meteor Electrical

QGROM25OPEN In-Stock

25mm Open PVC Grommets - (Pack of 50)

£4.43 inc. VAT

QGROM20OPEN In-Stock

20MM PVC Open Grommet

£2.33 inc. VAT

20MM PVC Closed Grommet with Meteor Electrical

QGROM20CLOSED In-Stock

20MM PVC Closed Grommet - (Pack of 100)

£3.50 inc. VAT

Choosing the right grommet

Grommets are a small item that matters on every job involving metal back boxes, enclosures or consumer units. The right one protects insulation and keeps dust out of the enclosure.

Open or closed grommets

Open grommets have a hole ready for the cable, so they are quick to fit in knockouts on steel back boxes and adaptable boxes.
Closed (blind) grommets have a membrane that is pierced to the cable size, giving a closer fit and helping keep dust out. They can also blank unused holes.
Grommet strip fits around non-standard openings where a round grommet will not work.

Sizing

Grommets are sized by the hole they fit, typically 20mm or 25mm to match standard knockouts. Check the diameter of the hole and the size of cable you are passing through. For closed grommets, pierce or cut the membrane just smaller than the cable so it grips the sheath snugly.

Installation and compliance

Fit the grommet before pulling the cable through, so the edge is protected from the start. In consumer units and distribution boards, use the correct grommets so the enclosure keeps its fire and ingress protection; current wiring regulations require gaps to be minimised in these enclosures, so check BS 7671 and the manufacturer's instructions. Where a seal against water is required, use an IP-rated cable gland instead of a grommet. For long or rectangular cut-outs, see our grommet strip range.

Buying from Meteor gives you access to more than 5,000 products and 100+ trade brands from a family-run wholesaler with over 40 years in business. Orders over £30 / €35 ex VAT ship free, and credit accounts are available subject to approval.

FAQ's Ask Your Own Question

What size grommet do I need for a back box knockout?: Most metal back box knockouts are 20mm, so a 20mm grommet is the standard choice. Larger adaptable boxes and enclosures may have 25mm knockouts. Measure the hole diameter rather than the cable, as grommets are sized to the opening they fit into.
What is the difference between open and closed grommets?: An open grommet has a ready-made hole for cables to pass straight through, making it fast to install. A closed grommet has a solid membrane that you pierce to suit the cable, giving a tighter fit and better protection against dust. Closed grommets can also be left intact to blank off unused holes.
Are grommets needed in plastic back boxes?: Plastic back boxes often have built-in flexible entries or smooth knockouts, so separate grommets are not always needed. Metal boxes have sharp edges that can damage insulation, so grommets should be fitted there. Follow the box manufacturer's instructions and check current wiring regulations for your specific installation.
Do grommets make an enclosure waterproof?: Standard PVC grommets protect cables from sharp edges and help limit dust, but they are not designed to make an enclosure waterproof. For outdoor or wet locations, use IP-rated glands and enclosures that are designed to seal cable entries. Check the IP rating needed for the location before choosing.
How do I fit a closed grommet?: Push the grommet into the hole so the groove seats on the metal edge, then pierce the centre membrane with a screwdriver or sharp tool, keeping the opening slightly smaller than the cable. Push the cable through so the membrane grips the sheath. Avoid cutting the hole too large, as this reduces protection.
Can I buy grommets in bulk for trade jobs?: Yes, grommets are sold in packs of 50 and 100, and trade account holders receive trade pricing. Credit accounts are available subject to approval. Call 028 8675 1515 (048 8675 1515 from ROI), Monday to Friday 8am to 5pm, to open an account or ask about larger quantities.