Fasteners for Electrical Panels and Enclosures

Control panels, switchboards, feeder pillars and junction boxes use many small fasteners: screws for covers and components, nuts fixed to thin sheet, and washers that keep earth connections tight. This page lists what panel work usually needs and how to choose the material. JMIKS Fasteners supplies them from Ahmedabad.

Fasteners Used in Panels and Enclosures

Machine Screws: Which Head?

• Pan Phillips (DIN 7985, ISO 7045): the head sits on the surface, for components, terminal rails and covers.
• CSK Phillips (DIN 965, ISO 7046): sits flush, for hinges and front panels where nothing should stick out.
• Button head (ISO 7380): low and rounded, with no sharp edges, for doors and covers that people touch.
• Allen cap (DIN 912, ISO 4762): takes the highest torque, for mounting plates, frames and heavy components.

Small components commonly use M4 to M6 screws, and busbar joints M8 to M12 bolts. Your panel drawing gives the exact sizes.

Nuts for Sheet Metal and Vibration

• Weld nuts (DIN 929 hex, DIN 928 square) are projection welded to the sheet, so a bolt can be fitted from the other side without holding a nut.
• Nylock nuts resist loosening on doors, fans and vibrating equipment. Standard nylon inserts are rated to about 120 °C, so keep them away from heaters and resistors.
• Flange nuts have a built-in washer. The serrated type locks better but marks paint; use the plain type on painted surfaces.

Washers for Earthing and Busbars

Star washers have teeth that cut through paint and oxide, giving a reliable metal-to-metal earth contact. Spring washers keep tension in joints that vibrate or heat and cool. On high tensile 8.8 bolts tightened to a high load they add little, so correct tightening matters more. Use a plain washer against painted sheet or copper.

In a busbar joint, current passes through the copper faces, not the bolt. The bolt only holds the faces together, so tighten it to the torque in the panel design; our bolt torque chart gives typical values.

SS 304 or Zinc Plated?

• Zinc plated steel is economical and suits dry indoor panels in control rooms. High tensile 8.8 zinc plated bolts give a strong clamp on busbars.
• SS 304 suits outdoor feeder pillars, humid areas and water, food or pharma plants, with no coating to wear away. Use SS 316 near the sea or chemicals.

Keep the screw, nut and washer in one material. Stainless threads can gall if driven too fast, so tighten steadily or use anti-seize. Compare grades in our SS 304 vs SS 316 guide.

Electrical Panel Fastener FAQs

Which screws are used in electrical panels?

SS pan Phillips and CSK Phillips machine screws fix components and covers. Button head screws suit doors, and Allen cap screws suit mounting plates and heavy parts.

Why are star washers used for earthing?

Their sharp teeth cut through paint and oxide layers and give a reliable metal-to-metal contact for the earth connection.

Are SS screws better than zinc plated screws for panels?

For outdoor, humid or coastal sites, yes: use SS 304, or SS 316 near the sea. In dry indoor panels, zinc plated steel works well and costs less.

Nylock nut or spring washer: which should I use in a panel?

Both resist loosening. A nylock nut needs no extra part but suits temperatures up to about 120 °C. A spring washer works with any nut and at higher temperatures.

Get a Quote for Panel Fasteners

Send the screw types, sizes, grades and quantities. Message us on WhatsApp at +91 90333 11425 or use our enquiry form, and we reply within one working day. See the full range in our catalogue (PDF).