WHY ACCURACY MATTERS

Every Meter Is Only as Accurate
as Its Standard

A billing meter is checked by a test board or field standard. That equipment is checked by a reference standard, and the reference standard traces back to NIST. If any link in that chain is off, every meter tested against it inherits the error. RADIAN builds and calibrates the standards at the top of that chain.

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Policy Statement

What Meter Accuracy Protects

Each meter on your system decides what a customer pays and what your utility collects. A meter that reads slow loses revenue on every kilowatt-hour. A meter that reads fast overcharges customers, and that turns into complaints, refunds and questions from your regulator. Either way, the result is only as trustworthy as the test that approved the meter.

Utilities test meters to prove they read correctly: when they arrive, while they are in service, and when a customer disputes a bill. Those tests are only defensible if the equipment used for them can show where its own accuracy comes from. That record is called traceability, and it is what regulators, auditors and accreditation bodies ask to see.

How Accuracy Travels From NIST to Your Meters

Each link in the chain is checked by a more accurate link above it.

NIST. The National Institute of Standards and Technology maintains the national measurement standards for the United States.
RADIAN’s accredited laboratory. Our ISO/IEC 17025:2017-accredited metrology lab keeps primary transfer standards traceable directly to NIST.
Your primary or lab standard. A RADIAN RD-22 Primary Transfer Standard (±0.005% typical) carries that traceability into your laboratory.

Your working reference standards. RADIAN RX-30/31/33 and other RADIAN reference standards are calibrated against it.
Your test boards and field equipment. WECO meter test boards, Powermetrix and UTEC field systems, and RADIAN RW-30X field standards use RADIAN references inside.
Every meter you install and test. Each result carries the accuracy of every link above it, with WATT-Net keeping the record.

What a Small Meter Error Costs

Meter errors look small as percentages but add up quickly across a service territory. Here is a simple example for a utility with 100,000 residential meters, each using 10,000 kWh a year at $0.15 per kWh (about $150 million a year in energy sales):

Average meter error	Yearly revenue affected
0.1%	$150,000
0.5%	$750,000
1.0%	$1,500,000

A slow meter loses that revenue quietly. A fast one bills customers for energy they didn’t use, which is harder to fix than it is to prevent. Accurate test equipment, with a documented chain back to NIST, is how a meter shop keeps these numbers close to zero and shows its work.

Try your own numbers, including what drift in a test standard costs, with our Meter Error Cost Calculator.

The RADIAN RD-22 on a transparent background.

Why Utilities Trust RADIAN at the Top of the Chain

Proof, not promises

300 million meters produced in the past 30 years are referenced to a RADIAN standard
Powering meter testing in 50 countries
16 energy measurement patents, including the autoranging inputs that protect RADIAN standards from wrong-tap connections
ISO/IEC 17025:2017-accredited calibration (certificate 3784.01) and an ISO 9001:2015-certified quality system
NIST-traceable calibration in our own metrology lab, including verification-only calibration of non-RADIAN AC energy reference standards
Designed, built, calibrated and serviced in Lafayette, Indiana by a 100% employee-owned company

Accuracy FAQ

What does "traceable to NIST" mean?

It means an unbroken, documented chain of calibrations links your equipment back to the national standards held by NIST, with the uncertainty known at each step. RADIAN's accredited lab keeps primary transfer standards traceable directly to NIST, so a RADIAN calibration certificate shows where your standard's accuracy comes from.

A young woman using a RADIAN DC reference standard on a WECO 4330X as a part of RADIAN Calibration Services.

How much more accurate should a reference standard be than the meters it tests?

A common rule of thumb is at least four times more accurate, so the standard's own error barely affects the result. RADIAN reference standards are built well beyond that margin for revenue meter testing. The RD-22, for example, is typically within ±0.005%.

How often should a reference standard be recalibrated?

Follow the manufacturer's interval and your own quality program. For the RD-22, that's 365 days. Many labs also cross-check standards against each other between calibrations, as described in our white paper on using three RD-22 units as one reference.

What happens if a reference standard drifts?

Every meter tested against it inherits the error until the drift is found, often at the next calibration. That can mean re-testing meters and re-issuing results. Regular cross-checks, and keeping more than one standard, catch drift early. See what drift can cost with our Meter Error Cost Calculator.

The RADIAN RS-933 on a transparent background (icon).

Can RADIAN calibrate standards from other manufacturers?

Yes. RADIAN Calibration Services offers verification-only calibration of non-RADIAN AC energy reference standards, as well as full calibration of RADIAN equipment in our accredited lab.