For electricians, digital multimeters are one of the most vital components in their tool kit, providing a wide array of functionality and enabling them to quickly work out what is happening in an electrical system.
Digital multimeters also allow electricians to determine that there is no voltage present, which is the most important step they can take to make sure of their own safety.
How Dangerous Are Digital Multimeters?
While determining the lack of voltage is a vital first step for electricians, taking it actually increases the level of risk that they will get an electric shock or cause an arc flash.
For the test to be properly completed, electricians need to get very close to circuit parts that could be energised and then touch them with small probes, so it is unsurprising that there have been accidents during testing and an electrician has been shocked or subjected to a dangerous arc flash event.
These shock hazards can take place if there has not been proper maintenance of test leads or the meter, and arc flashes may result from improper voltage rating for the meter, defective components or parts, or if there has been exposure to transient voltages that are outside of a meter’s normal operating conditions.
How To Avoid Voltage Transients
Voltage transients, also known simply as voltage spikes, is the term used for when a volt system that is supposed to have a voltage of no more than 480 gets driven up much higher, possibly even up to 10,000 volts. In plants, this can be caused by capacitors, variable speed drives and motors.
A voltage transient can also be caused by a lightning strike to an outdoor transmission line.
It is therefore vital for electricians to make sure they are using the correct digital multimeter for the job. The digital multimeter should not have a rating less than the recorded voltage of the equipment that is being tested.
It is also essential for the category rating to be correct. A category rating is the level of transient over-voltages that is able to be withstood by the digital multimeter, which is based mainly on the equipment’s location and how close it is to the source. The nearer outside, the higher the category rating will be required to be in most cases.
How To Avoid Meter And Probe Insulation Deterioration
When using a digital multimeter to perform tests, electricians should always wear rubber insulating gloves, but another method of protection lies with the actual probes.
The probes’ insulation needs to be examined to see if there is any indication of cracks or deterioration in order to make sure the electrician is completely protected from an electric shock.
The meter should also be thoroughly checked to make sure that it is working in the correct manner and in overall good condition.
Avoiding Human Error
Human error is often the cause of accidents, as complacency can set in when everything goes well for a long time.
Electricians need to be reminded of the dangerous nature of their job and how important the various checks and safeguards are.
Digital multimeters need to be treated as the critical aspect of protective equipment for electricians that they are, while also having their own risk factors fully understood.