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UKAS ISO17025:2017 Calibration Accreditation (Power)

In 2013, Newtons4th UK was awarded Calibration Laboratory Accreditation by UKAS to ISO17025:2017 for Voltage, Current, Power, Phase, Harmonics and Flicker. Our incentive to achieve this accreditation was a commitment to the highest level of metrology in our field of activity and the desire to provide accredited calibration certificate with every new power analyzer we ship. This is a first in our industry and gives users of N4L power analyzers a higher level of standard calibration than any other power analyzer manufacturer. A great amount of time and engineering effort has also been spent on implementing a sophisticated IEC61000-3-2, IEC61000-3-3, IEC61000-3-11 and IEC61000-3-12 harmonics and flicker calibration facility. This additional certification is also accredited, making N4L the first power analyzer manufacturer to offer power analyzer products with accredited certification to presently defined measurement criteria for IEC61000 Harmonic and Flicker standards.

Our schedule of accreditation is available to view on the UKAS website via this link

N4L ISO17025 Calibration LAb

UKAS (ISO17025) Schedule of Accreditation
Signal AmplitudeFrequency Range
Voltage Sine Amplitude1V to 1008V 16Hz to 850Hz
Voltage Harmonic Amplitude0V to 302V16Hz to 6kHz
Current Sinewave Amplitude100mA to 48A16Hz to 850Hz
Current Harmonic Amplitude0A to 15A16Hz to 6kHz
Current to Voltage Phase Angle-180° to +180°16Hz to 850Hz
Apparent Power (VA Product)100mVA to 48.4kVA16Hz to 850Hz
AC Power (Reference Source)0W to 48.4kW16Hz to 850Hz
AC Power (Calorimetry) (New for 2017)1W to 5W45Hz to 2MHz
Calibration of Impedance Networks (per IEC61000)33mOhm to 400Ohm45Hz to 850Hz
Current Harmonic Amplitude to IEC61000-4-70A to 6A16Hz to 6kHz
Flicker to IEC61000-4-15Pinst (Sinusoidal Modulation)As Per IEC61000
Pinst (Rectangular Modulation)
Frequency Changes
Distorted Voltage with Multiple Zero Crossings
Harmonics with Sidebands
Phase Jumps
Rectangular Changes with Duty Cycle

N4L Calibration Philosophy

N4L products combine market leading accuracy with exceptional stability so that users can be confident in the long term integrity of measurements. While we recommend re-calibration every 12 months, stability over time and a conservative approach to our product specification allows our products to remain within specification for much longer periods of time. This is proven by many N4L customers who, working in accordance with their own ISO9001 certification, are able to select 24 month calibration periods for N4L products they own.

Alongside our UKAS ISO:17025 accreditation which provides voltage, current, phase and power calibration up to 850Hz plus calorimetric power to 2MHz, we have developed a proprietary high frequency multi channel signal generator named the ACC-IV (Automatic Calibration Controller 4). Combined with custom designed amplifiers, the ACC-IV provides high frequency voltage and current sources at a higher signal level than commercially available calibrators and provides N4L with the means to calibrate our power analyzers over a wider frequency range than any other company.

The term “calibration” is commonly used in relation to measurement instrumentation and yet is surprisingly misunderstood.

Common mistakes in understanding range from the belief that a unit will be more accurate after calibration when in fact most conventional calibrations don’t change the accuracy at all, or that any ISO17025 ‘accredited’ calibration will give a greater assurance of accuracy than an ISO17025 ‘traceable’ calibration, which is often not true.

Since N4L offer a wide range of calibration options including ISO17025 accredited calibration with a broader schedule of accreditation than most power metrology laboratories, we can consider the options impartially.

In the document linked to below, we summarize fundamental elements of calibration and the benefit to a user of measurement optimization during any calibration.

Power Measurement Calibration – What makes N4L different?, PDF 371kb

The exceptional detail and accuracy of our calibration is achieved by unique calibration hardware, combined with processes that come from an absolute commitment to best metrology practice. This includes standard calibration with over 200 calibration points at different levels and frequencies to the adjustment points we use for measurement optimization, therefore ensuring linearity of the instrument under test and also the integrity of calibration. An investment in 10 fully automated test systems allows N4L to provide this highest level of calibration with each and every power analyzer we supply.


Every power analyzer is supplied from new with two calibration certificates

1. ISO17025 UKAS accredited calibration for Voltage, Current, Phase, Power (including low power for EN50564 and Energy Star) and PF up to 850 Hz.

2. Wideband Calibration certificate traceable to national standards covering up to 500kHz (PPA500), 1MHz (PPA1500/PPA3500) and 2MHz (PPA4500/PPA5500).

ACCIV Standard Calibration (Utilizing UKAS traceable instrumentation)
Signal Amplitude Frequency Range
Voltage Amplitude
+/-250uVpk to +/-400Vpk DC to 100kHz

Linearly reducing to +/-10Vpk 100kHz to 2MHz
DC to 2MHz
Current Amplitude +/-1mApk to +/-5Apk DC to 100kHz

+/-300mApk to 100kHz to 2MHz
DC to 2MHz

Optional calibration:

1. ISO17025 UKAS accredited calibration for Harmonics and Flicker in accordance with IEC61000-4-7/IEC61000-4-15

2. PPA5500-HF ISO17025 UKAS Calorimetry Certificate available upon request. For more information please contact us at

Our comprehensive calibration procedure is unrivaled in our sector* and we are confident that our power analyzers offer the highest wide bandwidth performance in the market.

*according to N4L research 2014

Relevant documentation: