What should a rice mill electrical BOQ contain?

Six sections: incoming supply and transformer, main PCC panel, motor control centre with a starter per drive, cabling and cable support, earthing and lightning protection, and lighting with small power. Under each, quantities and ratings rather than descriptions, and a schedule of drives listing every motor with its rating and what it drives.

What gets left off almost every BOQ?

Six things, in our experience: cable glands and lugs, cable tray and support steel, the earthing grid as distinct from the earth pits, power factor correction, plant and yard lighting, and spares. Together they are commonly 10 to 15 per cent of the electrical value, and they surface as variations after the order is placed.

Should the BOQ specify makes?

It should specify an approved makes list — two or three acceptable manufacturers per item — rather than a single make. That keeps the quotation comparable between suppliers while stopping anyone substituting something unknown. Tell us your approved list and we will quote strictly against it.

Do I need a single line diagram before asking for a quotation?

It helps a great deal, but it is not essential. If you have a drive schedule listing every motor with its kW rating and what it drives, plus the transformer rating and a rough site layout with distances, we can quote from that and produce the single line diagram as part of the job.

How should the BOQ handle spares?

As a separate priced section so it can be seen and, if the budget is tight, deferred consciously rather than by accident. At minimum: one spare contactor and overload relay of each frame size in use, one MCCB of the commonest rating, fuses, indicating lamps and a spare set of drive belts.

What Goes Into a Rice Mill Electrical BOQ

Start fromThe drive schedule — every motor, kW, and what it drives
Six sectionsIncomer · PCC · MCC · Cabling · Earthing · Lighting
Usually missingGlands and lugs · tray and support · earth grid · PFC · yard lighting · spares
SpecifyAn approved makes list, not one make

Start with the drive schedule

Before any of the six sections can be priced, somebody has to write down every motor in the mill. Not "motors as required" — an actual list. For each drive: what machine it is, kW rating, speed, whether it starts loaded, and roughly how far it sits from the panel.

A typical mill drive schedule runs from the paddy intake elevator through the pre-cleaner, de-stoner, husker, paddy separator, whitener or polisher bank, grader, aspirators and husk blowers, to the bagging point — plus the compressor, the water pump and anything on the dryer.

That one table decides the MCC size, the starter type for each drive, the cable sizes and the transformer rating. Everything downstream is arithmetic on it. If you send us nothing else, send us this.

The six sections

1 · Incoming supply and transformer

Transformer rating in kVA with vector group and percentage impedance
HT side protection as required by the licensee
LT side incomer — ACB or MCCB, rating and breaking capacity
Metering as specified by TPWODL for the connection class
Transformer plinth, fencing and the earthing associated with it

2 · Main power control centre (PCC)

Panel construction — sheet thickness, IP rating, form of separation, floor or wall mounted
Incoming device and busbar rating, with short-time withstand
Outgoing feeders to the MCC, lighting board and any separate load
Metering, CTs, indicating lamps, selector switches
Space heaters and thermostat — worth having in a mill's humidity

3 · Motor control centre

One starter per drive, each of the correct type — see DOL, star-delta or soft starter
Contactors rated for AC-3 duty, not AC-1
Overload relay per drive with the motor's full load current near the middle of its range
Local start-stop stations at each machine, with emergency stops
Interlocking so the line starts and stops in the right sequence and nothing runs into a stopped conveyor
Ammeter on the larger drives — the cheapest diagnostic tool in a mill

4 · Cabling and support

Power cable per feeder, sized on current and volt drop — see choosing plant cable
Control cable, screened where it runs alongside power
Cable tray, ladder, trunking and the support steel to carry it
Glands, lugs, ferrules and terminations, itemised by size
Conduit and accessories for the wired-in portions

5 · Earthing and lightning protection

Earth electrodes — body and neutral, counted separately, per IS 3043 practice
The earth grid itself: strip, run in metres, with joints and clamps
Equipment bonding to every motor frame, panel and structure
Test links, earth pit chambers and covers
Lightning protection where the building or a silo warrants it

6 · Lighting and small power

Plant floor lighting to a stated lux level, with fittings counted
Yard and security lighting, including poles
Socket outlets, welding points, maintenance supply
Emergency and exit lighting where required
Lighting distribution boards and their sub-circuits

The six that get left off

Glands and lugs. Every cable has two ends and every end needs a gland and a set of lugs. On a mill with sixty feeders that is a real number, and it is almost never in the BOQ we are sent.

Cable tray and support steel. The cable is priced; the thing that carries it is not. Tray, ladder, brackets, and the angle iron somebody has to fabricate.

The earthing grid, as opposed to the earth pits. Four pits appear on the BOQ. The hundreds of metres of strip that connect them to every frame in the building do not.

Power factor correction. Left for later, then discovered when the first bill arrives. On an HT connection billed on kVAh this is not optional — it is the fastest payback in the plant.

Yard and security lighting. Everyone remembers the plant floor. Nobody remembers the yard the trucks turn in at night.

Spares. One contactor and relay of each frame size, one MCCB of the commonest rating, fuses, lamps. A mill stopped for a two-hundred-rupee contactor during procurement season is an expensive lesson.

How to write it so quotations are comparable

Quantities and ratings, not adjectives. "Suitable cable" cannot be priced. "4C × 95 sq mm XLPE Al armoured, 180 m" can.
An approved makes list. Two or three acceptable manufacturers per item. A single named make invites a monopoly price; no list at all invites substitution.
State the installation conditions. Ambient temperature, whether cables are buried or on tray, how many share a route. These change cable sizes and therefore prices.
Separate supply from erection if you intend to compare a supply-only quotation against a turnkey one. Otherwise you are comparing different things.
Price the spares section separately so it can be deferred deliberately rather than dropped silently.

What we need to quote against it

If you have a full BOQ and a single line diagram, send them and we will price line by line against your approved makes. If you do not, send us:

The drive schedule — every motor, its kW, and what it drives
The transformer rating, or your sanctioned load if the connection is not yet taken
A rough site layout with distances from the panel to the far drives
Whether you want supply only, or supply with erection and commissioning

That is enough for a real quotation rather than a guess. Send it on WhatsApp or email and we will come back with an itemised list, and we will tell you which of the six commonly-missing sections your BOQ has left out.

What goes into a rice mill electrical BOQ