Electrical BOQ Mistakes to Avoid
A bill of quantities fails in the same few places: items that were never listed, specifications too vague to price, units that do not match how a supplier sells, and rates that look comparable but are not. This guide lists those mistakes in the order to check a BOQ, before it goes out for pricing.
Missing items and vague specifications
The most expensive BOQ mistake is an item that is simply absent — containment, earthing, labelling, testing, or commissioning time that everyone assumed someone else had included. The second is a specification that cannot be priced: a cable with no size, a board with no rating, a luminaire with no output. Every line should answer what, what size or rating, and to what standard, or the prices you receive will describe different things and cannot be compared.
Units, quantities and wastage
Quantities must use the unit the supplier actually sells in, and the takeoff must come from the drawings, not from a previous project scaled by feel. State wastage, offcuts and spares explicitly rather than hiding them inside quantities, so a reviewer can see whether they are reasonable. A BOQ whose quantities cannot be traced back to a drawing measurement is a BOQ nobody can audit — and audit is exactly what happens when a price is disputed.
Rates that cannot be compared
Two rates are comparable only if they include the same things: supply only, or supply and install; including terminations, testing and commissioning, or excluding them. List inclusions and exclusions on every section, keep provisional sums separate from measured work, and never compare a lump sum with a measured rate as if they were the same. When a rate looks far below the others, ask what it excludes before celebrating the saving.
A sane BOQ review sequence
Read the drawings first, then the BOQ, line by line, marking every item you cannot trace to a drawing, every specification you cannot price, and every rate whose inclusions are unclear. Fix those three lists before issuing for pricing, and keep a short assumptions and exclusions page with the BOQ so the next engineer — or a dispute — can see what was intended. A BOQ reviewed this way takes an extra hour and saves weeks of variations.
If you want a second pair of eyes on your own numbers or drawings before you decide, see the remote transformer services — documents only, fixed price, fixed turnaround, no site visit. For the wider testing picture, start with the transformer testing and commissioning guide.