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Frequently Asked Questions

The following is a list of frequently asked questions regarding calibration and our services. If the information you need isn’t supplied here, we recommend giving us a call and we’ll be happy to answer any questions you may have.

Calibration Questions


Over time the base accuracy (a known value) of your tester can change. This can occur as a result of many different factors ranging from a sudden surge of electricity to damage to the meter’s internal operation caused by accidental knocks. When this occurs, the meter’s accuracy ‘drifts’ from its normal state causing your instrument to become inaccurate.

Calibration is the process of checking that your instrument is operating at the correct level of accuracy. If there is a slight imbalance, a calibration technician will fix it and restore the meter to its correct working order. Similarly, if errors are being caused by faulty internal parts, calibration can help to discover and subsequently repair these issues.

In short, you need to calibrate your equipment as it could be inaccurate, and this may lead to the incorrect installation of equipment or an inability to identify faulty installations.

The price we charge for calibration depends upon the complexity of the instrument and the difficulty of the procedure. You can view our full calibration scope here, simply click the section you’re interested in and find your instrument.

When you send in your instrument you must also provide any leads, chargers or accessories that are used with it. We recommend doing this because a lot of faults with instruments can be found in their leads (for example), and by using your leads/accessories to calibrate your test equipment we can find problems that may otherwise go unnoticed.

If your meter fails the calibration process this generally means there is a fault with the unit. If there is a problem we will contact you to discuss the possible options. If we are able to repair your instrument it will be passed to the repair department who will supply you with a quotation for the repairs.

The inspection process can take up to a week, and a £45 inspection charge is applicable which will be waived should you go ahead with the repairs. If we are unable to repair your unit we can generally source a replacement or offer a discount on a new instrument.

We will never do anything to cause you to incur further costs without your permission.

Please note that when a tester fails calibration it is no longer eligible for the 3-day-or-free price promise.

Generally, most instruments should be calibrated annually, although there are exceptions. Further to this, test instruments should also be calibrated if you suspect that readings may be incorrect or out of specification.

Annual calibration applies even if the meter isn’t used frequently as factors such as moisture and low temperature can affect your meter’s operation. Therefore, if you’re going to use the test instrument again and the certificate has expired, it needs to undergo a new calibration.

Our three-day-turnaround service is available on selected instruments as standard. It starts from receipt of your items until their dispatch and is timed in working days only.

There are a few terms and conditions related to the 3-day-turnaround service, such as you must have included a payment/purchase order when sending in the instrument.

Full details of the service can be found here.

Nothing we do in our calibration procedure will affect your tester’s memory in any way. All your results will still be stored on your instrument.

Nevertheless, we recommend that you download all your results before sending your test meter for calibration. As, for example, if your instrument requires repair and we need to replace components/boards then we cannot guarantee that test results will be retained.

Repair Questions


If your tester is experiencing problems or has ceased working, PASS Ltd is able to help. To take advantage of our repair service, please visit the Repairs page and fill in our booking form or quote request form. Once received, a member of our team will be in touch with you to discuss the process further, and you will be able to ship your device to us for repair.

Collection & Delivery Questions

Collection & Delivery

To begin this process, please fill in our booking form or quote request form. Once received, a member of our team will be in contact to arrange pickup and organise payment. Alternatively, you may ship your tester to us yourself.

Our collections are arranged through DPD. This service will text or email you on the morning of your collection to inform you of the 1-hour window within which they anticipate collecting your instrument.

If the time isn’t convenient, please text back to re-arrange the collection time.

We recommend that you ensure your tester is as securely packaged as possible, as test equipment sent in inferior packaging can be damaged in transit.

Calibrations within our 3-day-turnaround will be sent back to you within 3 working days of receipt. We aim to turn around all other calibrations within 7 working days or fewer.

Minor repairs can take a few days to a 1 week. Major repairs can take up to 6 weeks, depending upon the scale of the issue.