Wall Plug

Which wall plug for which wall

A wall plug sits in a drilled hole and grips the wall when the screw goes in. The right plug depends on the wall: solid concrete, brick and stone; hollow brick and block; aerated concrete; or plasterboard. This page carries the plugs below. Mungo MN and MU plugs, grey universal plugs and spaghetti rolls are on the Mungo nylon wall plug page, frame fixings that go straight through a door or window frame are on the frame plug page, and toggles and metal hollow wall anchors are on the hollow wall anchor page.

• •Colour-coded tapered plugs (polyethylene): Hobson's traditional wall plug, colour coded to the screw gauge, a light duty plug for self-tapping, wood or coach screws in concrete, stone and brick. The tapered point eases it into the hole and it expands along its full length. Hobson lists electrical fittings, pipe saddles, light fittings, signage and brackets; it is light duty and Hobson publishes no load data for it.
• •Onego GN universal wall plugs (nylon PA6): for solid and hollow building materials, indoors and out, with wood, chipboard or metric screws. Knock-in protection stops early expansion, wings and a block profile stop it spinning, and teeth expand it evenly. Hobson lists brackets and fittings, bathrooms, electrical and interior work.
• •Mungo MQ Quattro (nylon PA6, with collar): four expansion zones, for concrete, solid and hollow clay and calcium silicate brick, lightweight concrete and aerated concrete, indoors and out. The collar stops it being pushed into a deeper hole. It is for face fixing (plug first, then the fixture), not through fixing.
• •Hollow brick plugs: Onego GLD in 6, 8 and 10mm and Mungo MLK 8 x 80 with a collar.
• •Onego GQ (solid materials), GU (cavity fixings) and GNK (with collar): Hobson names the use, but the documents we hold give no installation or load data for them.
• •Onego GD 14 x 100 scaffold plug: Hobson publishes no rating for it. Scaffold ties must use the anchor and tested capacity the scaffold designer specifies; do not use it to tie scaffolding on our say-so.
• •Mungo jet plugs for plasterboard: screw straight into the board with no pre-drilling. MFJ32-S is glass fibre reinforced polyamide; MJP32-S and MJP39-S are zinc plated metal. Each comes with a 4.5 x 30 PZ2 pan head screw.

Wall plug colours and screw gauges

Pick the colour for the screw you are using, then a length. Only count solid wall: Mungo's fastening dictionary says plaster, flagstones and insulation do not count as setting depth.

Universal wall plugs: GN drill, screw and load data

For the Onego GN, drill the hole the same diameter as the plug, to the hole depth below. The screw needs to reach the embedment depth in the plug, so screw length = embedment + the thickness of what you are fixing.

Hobson describes Nrec as the recommended tension (pull-out) load for the plug under defined conditions, to be used as a guideline for design and installation. The sheet gives tension only: no shear values, safety factor, edge distance, spacing or minimum wall thickness, so these figures do not tell you what happens near an edge, between plugs set close together, or in a thin wall. Where a failure could hurt someone or damage property, have an engineer or designer specify the fixing.

MQ Quattro collar plug: drill, screw and load data

Mungo's MQ data sheet includes a safety factor of 5 in its recommended loads, and says they must be reduced for combined tension, shear and bending, and for reduced edge distances or spacing (groups of anchors), with the data checked under the responsibility of an engineer experienced in anchorage. The MQ sheet gives no minimum edge distance, spacing or member thickness. Mungo's fastening dictionary adds that recommended loads are found in the laboratory without any influence of edge or centre distances, and that fixings in a group need a spacing of 3 times the setting depth to reach their full load.

Jet plugs for plasterboard

A jet plug screws straight into plasterboard with a PZ2 bit until its collar is flush, with no pre-drilling; in other materials Mungo recommends pre-drilling (7mm for the MFJ, 6mm for the MJP). The fixture must bear only on the plug collar, and the included screw allows a fixture up to 15mm thick. Mungo lists pictures, lamps, rails, skirtings and small wall-mounted shelves.

The loads below include a safety factor of 3. Like the MQ sheet, Mungo says they must be reduced for combined loads and for reduced edge distances or spacing, checked under the responsibility of an engineer experienced in anchorage, and the sheets give no edge distance or spacing figures.

Hollow brick, cavity, collar and scaffold plugs

These plugs complete the range. The documents Hobson publishes for this page give no drill size, screw size or load data for them, so check the pack, and do not use one for anything that carries load unless the designer specifies it.

How to fit a wall plug

From Hobson's GN sheet and Mungo's MQ sheet (for jet plugs, see above):

1. Drill a hole of the plug's diameter to the hole depth in the tables. Mungo's dictionary gives rotary drilling (no percussion) for aerated concrete and perforated brick, percussion drilling for solid brick, and SDS hammer drilling for concrete and natural stone.
2. Clean the dust out of the hole (Mungo says this is not needed in hollow brick).
3. Push the plug in flush with the surface.
4. Hold the fixture in place.
5. Drive the screw through the fixture into the plug and tighten until the fixing is secure.

Inside, outside and the screw you choose

Hobson lists the GN and MQ plugs and the MFJ jet plug for indoor and outdoor use; its MJP sheet lists indoor applications. Mungo gives its PA6 nylon a temperature range of -40 to +100°C.

The plug does not rust, but the screw can, so choose the screw for where the fixing is. Hobson rates zinc plated screws for indoor and non-corrosive conditions only. Mungo's dictionary limits zinc coated fixings to indoors (not wet rooms) and calls for A4 (316) stainless outside, in wet rooms, humid industrial areas and near the sea.

Wall plugs in Adelaide

Allmat supplies wall plugs, hollow brick plugs, masonry drill bits and screws to electricians, plumbers, builders, shopfitters and trade across Adelaide and South Australia. Add them to a quote with the rest of your list, and we will price the lot.

Questions