Question 1

What does the ISI mark on an electrical product mean?

Accepted Answer

It shows the product is certified by BIS as meeting the relevant Indian Standard, made under a BIS licence. The mark carries the IS number and the licence (CM/L) number, which can be checked on BIS's 'BIS Care' app.

Question 2

What is a BIS registration (R-) number?

Accepted Answer

Electronic and IT products under BIS's Compulsory Registration Scheme — including LED lamps, LED luminaires and many adapters — must be registered, and their packs carry an R-number. It can be verified with the 'BIS Care' app.

Question 3

How can I spot counterfeit electrical goods?

Accepted Answer

Warning signs: missing or blurred ISI/R-numbers, poor printing and spelling, unusually light weight (less copper or metal), loose or flimsy parts, no batch details, and a price far below the market. Verify licence numbers on BIS Care and buy through known distributors.

Question 4

What should I check on a product's pack?

Accepted Answer

The rating (W, A, V, size), the Indian Standard and ISI or R-number, the model or series and code, the batch or date, the warranty terms, the MRP, and the manufacturer's name and contact. Keep the pack and bill for any warranty claim.

Question 5

Which items move fastest in an electrical shop?

Accepted Answer

Everyday replacement items: LED bulbs and battens, switches, sockets, plates and holders, plugs and multiplugs, extension boards, fan capacitors and regulators, insulation tape, 1.5 and 2.5 sq mm house wire, and common MCB ratings. Seasonal items — fans in summer, heaters and geysers in winter — need planning ahead.

Question 6

How do I show customers the difference between warm and cool light?

Accepted Answer

A live demo board with the same fitting in 3000K, 4000K and 6500K side by side, switched on, explains it in seconds — far better than describing it. Show lumens on cards next to each light too.

Question 7

What tools should an electrician carry?

Accepted Answer

A proper voltage tester and a multimeter, insulated screwdrivers and pliers, a wire stripper and crimping tool with lugs and ferrules, a clamp meter, a drill and chisels, a conduit bending spring, a torch, insulation tape — and for bigger jobs an insulation tester and an earth tester.

Question 8

What is a clamp meter used for?

Accepted Answer

A clamp meter measures the current in a wire by clamping around it — no need to break the circuit. It's the quickest way to check the real load on a circuit, an AC or a pump, and to find which circuit is overloaded.

Question 9

What is a megger (insulation resistance tester)?

Accepted Answer

It applies a test voltage (commonly 500 V DC for household circuits, with loads disconnected) and measures the insulation resistance between conductors and to earth. Low readings reveal damp, damaged or deteriorated insulation before it causes faults.

Question 10

Why use lugs and ferrules on wire ends?

Accepted Answer

Fine-stranded wire squashes and loosens under a terminal screw; a crimped ferrule or lug gives a solid, tight connection that won't work loose and heat up. They make MCB, DB and appliance terminations far more reliable.

Question 11

How tight should terminal screws be?

Accepted Answer

Firm, to the torque the device maker specifies where given. Loose terminals overheat; over-tightening can crack the terminal or cut strands. Re-check terminals in DBs after the first few weeks, as copper settles.

Question 12

How do I estimate material for a wiring job?

Accepted Answer

Count points by type from the drawing, measure circuit routes from the DB to each point (add the drops to switches and sockets), then add 10–15% for wastage and loops. List boxes, plates, conduit, bends and accessories per point.

Question 13

Should wiring be quoted per point or as a lump sum?

Accepted Answer

Both are common. Per-point rates are easy to compare but must define what a 'point' includes (wire, conduit, box, switch). A lump sum for the whole job, with a material schedule naming brands and grades, avoids arguments later.

Question 14

How can I quickly check a customer's earthing?

Accepted Answer

Use a plug-in socket tester and measure neutral-to-earth voltage with a multimeter (it should be only a few volts). For a proper check, measure earth resistance with an earth tester and continuity of the earth to each point.

Question 15

What is lock-out, tag-out?

Accepted Answer

Before working on a circuit, switch it off, lock or physically secure the breaker so nobody can switch it back on, hang a tag saying who is working on it, and test that it's dead. It prevents someone switching on power while you're working.

Question 16

Who is allowed to do electrical installation work in India?

Accepted Answer

Installation work should be carried out by a licensed electrician or electrical contractor under the state's licensing rules, following the Central Electricity Authority's safety regulations and the National Electrical Code. Larger installations also need inspection and approval.

Question 17

How should wires and fittings be stored in a shop?

Accepted Answer

Keep coils and cartons dry and off the floor, out of direct sun and away from heat, stacked so labels are visible. Sell older stock first, and keep battery-backed products charged according to the maker's advice.

Question 18

What should a customer keep for a warranty claim?

Accepted Answer

The bill, the product (with its label and serial or batch intact), and ideally the pack. Warranty terms vary by product and are printed on the pack or bill — note what's covered and for how long at the time of sale.

Question 19

What is the National Electrical Code?

Accepted Answer

The National Electrical Code of India (SP 30), published by BIS, gathers the practices for safe electrical installations and points to the relevant Indian Standards, such as IS 732 for wiring and IS 3043 for earthing.

Question 20

Why should an electrician give the customer a drawing?

Accepted Answer

A marked plan of circuits, conduit routes and the DB schedule saves the customer money and danger later — no guesswork when drilling, adding points or tracing faults — and shows professional work.