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IS 2486 — Insulator Fittings for Overhead Power Lines

The core standard behind T&D line hardware above 1000 V — and the one almost no supplier page cites, even though state utility purchase specifications are written in it.

IS 2486 covers metal fittings of insulators for overhead power lines with a nominal voltage greater than 1000 V. Part 1 sets the general requirements and tests; Part 2 sets the dimensional requirements. These are the two parts a purchase specification normally names.

The clause that matters most to a fabricator is short and absolute: all ferrous parts exposed to the atmosphere in service, other than stainless steel, must be protected by hot dip galvanizing or another agreed means. The standard then hands the detail straight over — uniformity to IS 2633, coating conformance to IS 4759, and process practice to IS 2629.

What IS 2486 Part 1 specifies

  • Mechanical tests — ultimate strength, and slip strength for clamps, appropriate to the fitting type and its declared rating.
  • Galvanizing — hot dip galvanizing of all exposed ferrous parts, with coating uniformity verified to IS 2633 and conformance to IS 4759. Coating mass may be required in addition to the uniformity check.
  • Locking devices — requirements for ball-and-socket lockers and split pins, in materials such as phosphor bronze and stainless steel.
  • Dimensional conformity — addressed in Part 2, so that fittings from different suppliers interchange on the same line.

Why this page exists

Read our own audit findings, plainly.

We read a dozen competitor pole line hardware pages before writing this one. Exactly one cited a galvanizing standard at all, and not one cited IS 2486, a load rating in kN, or a coating figure in microns — while the actual purchase specifications those pages are chasing, WBSEDCL's among them, are written entirely in that language and call for 610 g/m² coating and NABL-accredited type-test reports.

So this page is not marketing. It is the specification language, stated accurately, by a manufacturer who galvanizes on its own floor and can hold the coating figure the specification asks for.

The galvanizing chain IS 2486 depends on

Requirement in IS 2486Where the detail livesWhat we do
Exposed ferrous parts to be hot dip galvanizedIS 2629 — process practice7.0 m in-house kettle at 450–460 °C, degrease–pickle–rinse–flux–dip
Coating to conformIS 4759 — coating mass610 g/m² (≈ 85 µm) held and certified where the specification calls for it
Coating to be uniformIS 2633 — copper sulphate dipDip test run on specimens; DFT readings per batch on production
Coating mass, where requiredIS 6745 — stripping methodRun on specimens when the buyer or inspector asks for mass rather than thickness
Fastener gradesIS 1367 — property classesFoundation and anchor bolts in classes 4.6, 5.6 and 8.8

This chain is the whole reason in-house galvanizing matters on hardware. When the coating requirement and the fabrication sit with two different companies, the responsibility for a failed dip test sits in the gap between them.

How Indo East supplies line hardware

  • Pole line hardware and fittings are supplied alongside our substation, transmission and distribution structures, so a utility or EPC buyer can source the structure and its hardware from one vendor and one coating standard.
  • Composite polymer insulators are supplied on the same basis. Voltage class, creepage and mechanical rating are quoted against the customer's specification — we do not publish ratings we have not been asked to hold.
  • Where a state utility specification demands NABL-accredited type-test reports dated within a stated period of bid opening, that is arranged against the order rather than claimed in advance.

Questions engineers ask

Answered from our own line, not from the standard's cover page.

What does IS 2486 cover?

Metal fittings of insulators for overhead power lines with a nominal voltage greater than 1000 V. Part 1 gives the general requirements and tests, Part 2 the dimensional requirements.

What does IS 2486 require for galvanizing?

That all ferrous parts exposed to the atmosphere in service, other than stainless steel, are protected by hot dip galvanizing or another agreed means. The detail is delegated: uniformity to IS 2633, coating conformance to IS 4759, and process practice to IS 2629.

Can Indo East meet the 610 g/m2 coating in utility specifications?

Yes, and we confirm it in writing at quotation against the section thicknesses in your drawing. 610 g/m² is approximately 85 microns; our published standard range is 75–85 microns and a 610 g/m² order is galvanized and certified at or above the equivalent.

Do you manufacture pole line hardware or buy it in?

Our range is mixed. Some items are manufactured at our Howrah works and some are supplied to the customer's specification and galvanized in-house. We state which is which on enquiry rather than leaving a buyer to assume — a point most supplier pages avoid.

Is there an Indian standard for cross arms?

No dedicated one. Cross arms are specified through the material and section standards — IS 2062 for the steel, IS 808 for the section — together with IS 2629 and IS 4759 for the galvanizing. Beware of specifications that cite IS 5561 here: that standard covers electric power connectors, not cross arms.

Which standard covers stay wire and earthing strand?

Stay and guy wire is IS 2141. Galvanized strand for earthing is IS 12776, and the earthing installation itself is covered by IS 3043. These are frequently confused in enquiries.

Related standards and pages

Send us the specification

Tell us the standard, the coating requirement and the component, and we will confirm in writing what we can hold and how we will certify it. Galvanizing is on our own floor, so the answer comes from us and not from a sub-contractor.

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