You have been issued a detection bill

The symptom: “A large charge for past months has appeared on my bill after an inspection.”

Short answer. Challenge the procedure before you challenge the arithmetic. A detection charge requires a documented inspection, an opportunity for the consumer to be present, and written notice before it is billed — and a charge that skipped any of those is defective regardless of whether the units are plausible. The forum for the amount itself is the Provincial Electric Inspector, not NEPRA.

Urgency: Act before the due date. Expect: Sub-divisional review takes two to four weeks. An Electric Inspector case commonly runs two to six months, during which a registered dispute protects supply.

Why this happens

An inspection found a defective meter: A slow or stopped meter that the consumer did not interfere with is assessed on past average consumption, without any penalty multiple.
Broken or missing seals: Seals are the company's evidence that the meter has not been opened. A broken seal shifts the case from fault to alleged interference, with a much harsher assessment basis.
A direct connection found on the premises: A cable bypassing the meter, whether installed by the current occupant or inherited from a previous one. Attribution is frequently the real fight here.
Load found materially above sanction: Where the connected load discovered on inspection far exceeds the record, the company may assess unbilled consumption on the difference.

What to do, in order

Obtain the inspection report and the calculation sheet. In writing, from the sub-divisional office. You are entitled to know the basis of the assessment: the period, the assumed units, and the reference used. A refusal to produce them is itself a ground.
Test the procedure against what happened. Was the inspection documented? Were you or a representative present? Was written notice served before the charge appeared on a bill? Was the assessment period within the limit? Each 'no' is a separate ground, and procedural grounds succeed far more often than arguments about consumption.
Register a written dispute immediately. This is what stops the disputed amount driving a disconnection. Verbal objections create no such protection. Stamp the copy.
Assemble your own evidence. The twelve-month consumption history, photographs of the meter and its seals, the meter change certificate if there was one, and any correspondence about a fault you reported earlier. A fault you reported before the inspection is close to decisive.
File with the Provincial Electric Inspector. Attach the disputed bill, the inspection report, your stamped complaint and the company's response or the absence of one. Proceedings are quasi-judicial and both sides are heard.
Consider paying under protest if supply is at risk. Where the premises cannot function without power, paying under protest preserves supply without conceding the case. Record the protest on the application and on the payment record.

What to take with you

The bill carrying the detection charge
The inspection report and calculation sheet
Twelve months of prior bills
Photographs of the meter, seals and terminal cover
Any earlier written report of a meter fault

Why procedure beats arithmetic

Arguing that the assessed units are too high invites a technical debate you are unlikely to win, because the company chose the basis and holds the records.

Arguing that the charge was raised without a documented inspection, without notice, or beyond the permissible period is a question of fact with a paper trail, and the paper trail is either there or it is not.

Start with the second. If it holds, the arithmetic never has to be litigated.

Inherited liability on a purchased property

A detection charge arising from a bypass installed by a previous occupant still attaches to the meter, and supply to the premises is what gets disconnected.

The practical protection is a no-dues certificate obtained from the company before a property transfer completes. Obtained afterwards, it is worth very little.

If it stalls, escalate in this order

Sub-divisional officer, in writing, for the report and the review
Executive engineer at the division
Provincial Electric Inspector for the assessment quantum
NEPRA where the complaint is about the company's conduct rather than the amount

Attach the earlier stamped applications at each rung. Starting the story again from the beginning at every level is the slowest possible way to escalate.

Frequently asked questions

Can my supply be disconnected while the detection bill is disputed?

Once a dispute is formally registered and on record, disconnection for that disputed amount is not supposed to proceed. The protection depends entirely on the dispute being in writing with a diary number — a conversation at the counter does not create it.

How far back can a detection bill go?

The assessment period is limited under the consumer service manual and depends on when the defect is held to have begun and whether notice was given. A charge reaching back further than the applicable limit is challengeable on that ground alone.

Should I hire a lawyer?

For a modest domestic assessment, a well-documented application usually suffices. For a large industrial assessment, or where tampering is alleged and criminal exposure follows, representation is worth it.

Background reading

All 17 procedures are listed in the help centre index. For company contact details and helplines, see complaints.