Electrical Design, Earthing and Lightning Protection in Bangladesh

Yes, in practice. RSC and most buyer electrical audits ask for an up-to-date single line diagram showing every panel, breaker rating and cable size, and auditors check it against what is installed. Without one, overloads and wrong breaker sizes are hard to prove or rule out, so many corrective action plans start with redrawing the SLD.

Earthing gives fault current a safe, low-resistance path to ground so breakers trip and metal parts never stay live. Lightning protection intercepts strikes on the roof and carries them down to earth outside the structure. They are separate designs, but IEC 62305 calls for the lightning earth to be bonded with the building's other earths so dangerous voltage differences cannot build up.

It depends on the connected load, the supply voltage (11 kV or 33 kV), the number of distribution boards and circuits, the switchgear brands specified, and whether existing panels can be reused. Drawings alone cost far less than a sub-station. We give a written, itemized quote after a free site survey, so you can compare it line by line.

BNBC 2020 Part 8 for building electrical services, IEC 60364 for low-voltage installations, IEC 61439 for switchboard assemblies, IEEE 80 for sub-station earthing and IEC 62305 for lightning protection. Where a buyer or insurer names another standard, such as NFPA 70 or NFPA 780, we design to that and state it on the drawings.

Mostly, yes. Surveys, drawings and most earthing work happen while the factory runs. Panel replacement and sub-station changes need short, planned shutdowns, which we schedule for weekends, holidays or night shifts and prepare in advance so the outage covers only the changeover itself. The shutdown plan is agreed in writing before work starts.