Meter seals, tamper flags and why you must not touch them
Short answer. Seals are the distribution company's evidence that a meter has not been opened since installation. A broken seal converts any billing question into an allegation of interference, with a far harsher assessment basis and the burden of explanation on the consumer — regardless of who broke it or why.
Who this is for: Every consumer, and particularly anyone considering having a private electrician work near the meter, or who has found a seal broken.
What is sealed and why
The terminal cover, the meter body cover, and on current-transformer installations the CT chamber. Each carries a numbered seal recorded against the account at installation.
The numbers matter. An intact seal with a number that does not match the record is treated the same as a broken one, which is why noting the numbers after any meter work is worth the thirty seconds it takes.
Electronic tamper detection
Modern meters log events: cover opening, strong magnetic fields near the meter, reverse current flow, and missing neutral. Each is time-stamped in memory that the consumer cannot access and cannot clear.
A magnet placed on a meter is detected and logged by every current-generation meter. The practice persists anyway, and the log is what makes it indefensible when the meter is eventually downloaded.
If you find a seal broken
Report it in writing immediately, with photographs, before anyone else notices. Voluntary disclosure is treated completely differently from discovery during an inspection.
Seals do get broken legitimately — by a technician doing authorised work who failed to reseal, by weather on an exposed installation, or by physical damage. None of those help you if the discovery is made by an inspection team six months later.
Work near the meter
Any work requiring the terminal cover to be opened is the company's work, not an electrician's. This includes a service cable replacement, an upgrade to the incoming supply and a meter relocation.
A private electrician who opens a sealed cover has created a problem that will surface later and will be difficult to explain, however innocent the intention.
Frequently asked questions
My seal broke when the technician replaced my service cable. Am I liable?
Not if the work was authorised, but you need the record to prove it. Get the job reference and photograph the resealed meter with the new seal numbers before the crew leaves.
Does a tamper flag automatically mean a detection bill?
It triggers an inspection rather than an automatic charge. A flag with an innocent explanation — a nearby magnetic field, a genuine neutral fault — can be explained, but the explanation has to be made and it is far easier before an assessment has been raised.
Related meter guides
Go further
All 10 guides are listed in the meter guides index. To check the reading against your actual bill, open the official duplicate.