Technical guides
Straight answers to the questions that come up before anyone knows a part number. Written by people who sell this equipment every day, and who would rather you specified it correctly than bought it twice.
Which MCB curve should you use: B, C or D?
B curve trips at 3–5 times rated current and suits resistive loads like lighting and heaters. C curve trips at 5–10 times and is the general-purpose choice for mixed domestic and commercial circuits. D curve trips at 10–20 times, for motors and transformers with high inrush current.
Read the full guide →FR, FRLS or LSZH cable: what is the difference?
FR cable resists spreading flame. FRLS adds reduced smoke and lower acid gas. LSZH, also written LS0H or HFFR and covered by IS 17048, contains no halogens at all, so it produces very little smoke and no corrosive gas. Specify LSZH wherever people must evacuate through the smoke.
Read the full guide →How do you choose the right cable size?
Start from the design current of the load, then apply derating factors for ambient temperature, grouping with other cables, and installation method. Check that voltage drop over the full run stays within limits, usually 3% for lighting and 5% for power. The larger of the two results sets the size.
Read the full guide →MCB, RCCB, RCBO or AFDD: which protects against what?
An MCB protects the wiring from overload and short circuit. An RCCB protects people from electric shock by detecting earth leakage. An RCBO combines both in one device. An AFDD detects the arcing in damaged wiring that causes fires but never draws enough current to trip an MCB.
Read the full guide →BIS QCO 2026 for electrical accessories: what changed?
The January 2026 amendment removes the insulating-tape entry for IS 7809 (Part 3/Section 1):1986 from Table 1 of the Electrical Accessories QCO. Cable trunking and ducting under IS 14927 (Part 2):2001 already appeared in the original order. Check the applicable standard, commencement provisions and any later exemptions for the specific product.
Read the full guide →Which IP rating do you need for an enclosure?
An enclosure's first IP digit describes protection against solid objects and its second describes water protection under specified tests. Choose the rating against the actual exposure and the manufacturer's installation conditions. IP ratings alone do not establish UV resistance, corrosion resistance or suitability for every outdoor, washdown or flood condition.
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