Electrical items look like commodities, and that is exactly why buyers get caught out by them. A bulb that dims in six months, a cable that runs hot, or a switch that sparks are all failures that started with a purchasing decision made on price alone.
This guide covers the items most offices, shops, and small factories buy most often: LED lighting, cables, and switches and breakers. It is general guidance, and installation should always be done by a qualified electrician.
LED lighting: buy lumens, not watts
Watts tell you how much electricity a light uses. Lumens tell you how much light it gives. With LEDs, the two are no longer tightly linked, so always compare lumens. As a rough guide, an LED bulb of about 8 to 10 watts gives the light of an old 60-watt incandescent bulb, around 800 lumens.
Choose the right colour temperature
- 2700 to 3000 K (warm white): waiting areas, lounges, and hospitality spaces.
- 4000 K (neutral white): offices, classrooms, and retail, where you want clear light without harshness.
- 6000 to 6500 K (cool daylight): warehouses, workshops, and areas where detail and alertness matter.
Mixing colour temperatures in one room looks patchy. Use the same temperature across a space.
How much light does a room need?
Offices are commonly lit to about 300 to 500 lux on the work surface. A quick estimate: lumens needed ≈ room area in square metres × target lux ÷ utilisation factor (around 0.5 is a common allowance for a typical room).
For a 20 m² office at 400 lux, that is 20 × 400 ÷ 0.5 = 16,000 lumens. A 40 W LED panel giving about 3,600 lumens would need around five panels. This is a rule of thumb. A lighting designer's calculation will be more precise, but it stops you buying half the light you need, or twice.
Signs of a good LED product
- Lumens, wattage, colour temperature, and warranty printed on the pack.
- A well-made driver and heat sink. Cheap LEDs often fail because of heat, not because the LED chip dies.
- Minimal flicker, which you can check by filming the light with a phone camera and looking for bands.
- A colour rendering index (CRI) of 80 or higher for offices and shops.
- A recognised standards mark and a manufacturer or importer who will honour the warranty.
Cables: size matters more than price
The cable's conductor size decides how much current it can carry safely. An undersized cable heats up, degrades its insulation, and is a fire risk, and you will not see the problem until it happens. Match the cable size to the load, and match the circuit breaker to the cable, not the other way round.
- Check the conductor size and the manufacturer's name on the insulation, not just on the drum label.
- Check that the coil length matches what is stated, since short-length coils circulate in the market.
- Choose copper conductors with good-quality insulation from a reliable manufacturer.
- Let your electrician confirm sizes for each circuit.
Switches, sockets, and breakers
These are handled every day and carry real current, so they deserve better than the cheapest option. Look at the amp rating printed on the item, the quality of the contacts and the plastic, and whether it fits properly in the box. In wet areas such as kitchens and washrooms, ask your electrician about residual-current protection (an RCD or earth-leakage breaker), which cuts the power quickly if current leaks to earth.
Keep a small maintenance stock
Keep around 5 to 10 percent spare bulbs and tubes of each type you use, plus a few switches and fuses. Buying the same model later can be difficult, and mixing different models leads to colour differences you will notice.
Safety first
Do not attempt to install or replace fixed wiring, breakers, or distribution boards yourself. Use a qualified electrician, and follow the applicable electrical codes and your utility's requirements.
What switching to LED can save
As an illustration, suppose you replace 100 old fluorescent tube fittings with LED tubes that use about 18 watts less each, and the lights run 10 hours a day for 26 days a month. The saving is 18 W × 10 h × 26 days = 4,680 Wh, or about 4.7 kWh per fitting per month, and roughly 468 kWh across 100 fittings. Multiply by your tariff to see the monthly figure. LEDs also last longer, which cuts replacement labour, particularly in high ceilings.
Common mistakes
- Comparing bulbs by watts instead of lumens.
- Mixing colour temperatures in one room.
- Choosing cable by price rather than conductor size.
- Fitting a breaker rated higher than the cable can carry.
- Buying a full stock of one unknown LED model without testing a sample for a month.
- Forgetting spare bulbs, then finding the same model is out of stock.
BST PVT LTD supplies LED lighting, cables, switches, sockets, and other electrical items to offices, shops, schools, and factories across Karachi and Pakistan. Send us the rooms or circuits you are working on and we will quote the right items and quantities.