How to Troubleshoot an Obsolete Kwh Meter

Introduction

Troubleshooting an obsolete kWh meter can be challenging, but is often necessary to determine why it is no longer accurately measuring electricity usage. kWh (kilowatt hour) meters are used by electric utilities to measure how much electricity a customer uses over time. Older analog kWh meters can become obsolete as they wear out over decades of use. However, with some basic diagnostic tests, you can often determine what is wrong with the meter and whether it needs to be replaced. In this guide, I'll walk through the step-by-step process for troubleshooting an obsolete or malfunctioning kWh meter.

Safety Precautions

Before doing any troubleshooting on a kWh meter, it's absolutely vital that you take proper safety precautions:

• Turn off the main breaker supplying power to the meter. This ensures the meter is not live when you are testing it.
• Verify power is off by checking with a non-contact voltage tester. Make sure there is no voltage present at the meter.
• Only work on the meter if you are experienced with electrical equipment and metering. If not, contact a qualified electrician.
• Use appropriate personal protective equipment like insulated gloves and wear safety goggles.
• Never open or dismantle the meter itself as that can expose dangerous live components.

Troubleshooting should only be done with the power off for safety. Only verify readings when power is restored.

Physical Inspection

The first step is a thorough physical inspection of the obsolete kWh meter:

• Look for any damage or wear on the meter casing that could allow dirt, moisture or insects inside. Damaged seals can compromise accuracy.

• Inspect the meter display for any cracks or malfunctions. Check that it is clearly displaying kWh usage. If not, the display could be broken.

• Verify the meter wiring to ensure all connections are intact and corrosion free. Loose or corroded connections can impact readings.

• Ensure the meter base is sealed properly without gaps for water intrusion. Small cracks can eventually lead to internal damage over time.

• Check for signs of internal condensation or corrosion like fogging or rust inside the glass meter cover. This indicates a defective seal that is impacting accuracy.

Any physical wear, damage or condensation inside the meter indicates it may need replacement.

Verify Meter Register Operation

With the power still off, you can manipulate the meter dials to verify the register is working properly:

• Spin the dial with your fingers - the wheel should turn freely without jamming.

• Try advancing each digit on the display - they should increment properly without sticking.

• Check that the dials reset back to zero when rotated backwards.

If any digits are stuck, jammed or failed to reset, the mechanical register likely has an internal defect and needs replacement.

Check Meter Accuracy

To check accuracy, the meter needs to be powered up safely. This should only be attempted by a qualified electrician:

• Turn the main breaker back on to energize the meter. Again verify it is live.

• Clamp a separate reference amp probe securely around the main feeder wire connected to the meter.

• Load the electrical circuit by turning on appliances.

• Check the amperage reading on the reference probe and compare it to the kWh usage increase on the meter.

• Calculate the wattage consumed over time based on the amps and time elapsed. Compare this to the kWh increase displayed.

• They should correlate closely if the meter is measuring properly.

• Check accuracy at both low and high loads for consistency.

If the metered usage is significantly different from the calculated wattage consumption, then the kWh meter is likely defective and should be replaced.

When to Call an Electrician

If you determine the obsolete meter is damaged or inaccurate through testing, then replacement is likely needed. Meter repair is not recommended. However, meter replacement should only be done by qualified electrical personnel due to the high voltage danger. Never remove or replace a meter on your own. Instead, contact your electric utility to schedule professional replacement of an obsolete, damaged or inaccurate kWh meter.

Conclusion

With this process for physical inspection, register testing and accuracy verification, you can determine if your obsolete kWh meter needs professional replacement. Always take proper safety precautions when troubleshooting electrical meters. Reach out to your electric utility if you confirm your meter is defective so it can be swapped with a new accurate meter. They can ensure your electric usage is measured correctly going forward.