Convenient Measuring of Current on Appliances and Devices

Featured Image found, in part, at the Following Link: 

Amprobe 330 – TRMS Motor Maintenance Clamp Meter (1000 A AC/DC)

This Blog Entry is a result of the Humidifier Blog I did recently. Measuring the Current of Vicks Vaporizer was a way to determine how much current, in my case, was needed to produce an adequate output of steam with the Unit that I have (it’s seen prior use), the water that I have (it’s not a good match for this type of Vaporizer) and the careful addition of salt to increase the conductivity in the water.

The Unit is rated at 5.8 Amps Maximum, often runs between 1 and 2 Amps, in my case produced more steam in the 2 to 3 Amp Range, and in the 3 to 3.5 Amp Range, the steam was significant. If you keep topping off the water, and adding Salt, it’s possible for the Salt to become Concentrated, so every few Fills for the Vaporizer, I cleaned the Tank and the Steam Unit according to the Instructions and started over.

So, it’s important to know the current on an Appliance or Device at times. In the Old Days, the De-energized Circuit Needed to be Opened, the Wire Cut or Removed from a Terminal, and the Meter Placed In-Series with the wire, to measure the current (then the power was restored). It’s more dangerous, it’s invasive, and it’s needless these days.

As Electrical Current Flows in a Conductor (hereafter called a “wire”), there is a Proportional Magnetic Field that expands and contracts in the wire with Alternating Current (AC), or a Magnetic Field is established of a specific intensity in association with a DC Current, that corresponds to the Amount of Current Flowing in both cases. The more common “Clamp Ammeter” measures AC Currents but not DC. But there are AC/DC Clamp Ammeters available.

To measure the Current, One of the Conductors needs to be Separated from the other, usually the Hot wire and the Neutral, and only the current in the single wire measured.

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For Plug-In Equipment, Line Splitter’s were developed and sold, and they are used simply by Plugging them into the Receptacle, Plugging the Device into the Splitter, and using the Clamp Ammeter in the Splitter openings for the measurements. Multiple Manufacturers offer Splitters to be used with Clamp Ammeters.

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See Image Below for this Section:

Internal Construction of the Ampprobe ELS2A Splitter.

If you Clamp on the Assembled ELS2A on the opening closest to the Plug End (x1), the Neutral Wire is on Top and the Hot Wire on the Bottom (see Lower Image directly below). Clamping the Neutral will show the Same Current as the Hot if the Device is Functioning Properly. On the Receptacle End (x10), the Extra Loops of the Hot Wire can be seen. There would be 10 Passes of the Hot Wire on the Lower Side of the Opening (as shown), the current would read 10 Times Higher than it actually is, and the Clamp Meter Displayed Result would need Divided by 10 to get the actual current.

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Below: The Clamp Ammeter has a Display Light that I forgot to use on the Images to the Right.

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All Images In this Blog Entry Created with GIMP Using Personal Photos, Photos Sourced Elsewhere, and Drawings. 

Below is the 1st Style Clamp Ammeter I had even seen. A friend used one for his Refrigeration Business. The Accessories are Unique, but Care Must be Taken Using them to Prevent the Shunt from Being Attached when the Splitter is Plugged-in to a Receptacle, as the Shunt will cause a Short, Injury and Equipment Damage is Possible, Tripped Panel Breaker/Blown Fuse, etc.

Created with GIMP


The Functions of the Attachments can be seen in the Following Drawing, except for the Voltage Test Leads and the Continuity Accessory shown Bottom Left. The Yellow Probe Accepts a Battery and is used, in conjunction with another Test Lead, with the Meter on Equipment that is Verified as Deenergized to Measure Resistance and Continuity. With the Resistance/Continuity Lead Removed from the Meter, the Black and Red Leads can be used to Measure Voltage. Each Measurement, Amperage, Voltage, and Continuity, have a Separate Dial that the Rotary Dial must be set to Prior to Use. Remove All Leads before Using the Clamp for Amperage Measurements. 


The Top Drawing Shows that the Alligator Clips would be Attached in series with a component in a Circuit. That Current would flow into one side of the Splitter, is Shorted Over to the other side of the Splitter via the Shunt, and back to the Circuit. Taking the Measurements at the x1 and x10 Points would work normally.

The 2nd Accessory is intended to maintain the Ground for the Appliance or Device, while providing a Testing Point for the Splitter to be attached and measurements taken. The Energized Wire enters the Accessory, is sent to the Testing Plug for the Splitter, flows into one side of the Splitter, is Shorted Over to the other side of the Splitter via the Shunt, back to the Ground Accessory Hub and into the Plugged-in Device or Appliance. Taking the Measurements at the x1 and x10 Points would work normally. The Newer Ampprobe ELS2A Splitter carries the Ground through the Splitter, Eliminating the need for the this Device to maintain the Ground.

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An HT Instruments Splitter with Additional Opening.

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This Splitter is Unique for a Few Reasons. Physically, there is a Short Cord with Plug on one end, and a Short Cord with Outlet on the other end. 
PE = Protective Earth (Ground Leakage) L-N is Leakage Line/Neutral
  • Similarly to the Ampprobe ELS2A, there are Voltage Check Points, but Checking to Ground is also Possible on this Unit.
  • It shows where to Check for Ground Currents (mA PE)
  • It shows where to Check to see if there is an Imbalance in the Line and Neutral Currents. Differences in Line to Neutral Currents is how a Ground Fault Current Interrupter (GFCI) works. If the Current is the same in Both Conductors, no GFCI Fault Exists. If the Current is Greater in the Line than the Neutral, the Current is flowing somewhere else, and the Device Trips when the difference is great enough. You can Measure the Actual Difference at mA L-N. If 3 Amps were in the Energized Lead, and 2 Amps in the Neutral, the Meter will read 1 Amp.
  • In the Absence of Ground Currents, it should be possible to Measure the Appliance Current in the Top or Bottom of the Ax1 Opening. Using the Bottom Opening, the Clamp will measure the Current in the Electrically Energized Lead. In the Ax10 Position, the Neutral Passes the Loop of the Electrically Energized Wire (Top), and this may Improperly Reduce the Current Read at the Ax10 Position. The Manufacturer marks it to Not Take Measurements at the Side of the Loop where the Neutral Passes, and there are only 9 Conductors in the Loop at this point, and 10 at the Bottom, so Reading at the Bottom is the only Correct way.

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Take Aways on this Blog Entry. 

  • Ammeters Originally Needed Placed in Series with the Circuit to Measure Current. 
  • Clamp Ammeters were developed, and they can be placed over a wire to determine how much current is flowing in the wire. 
  • Clamp Ammeters were largely for AC, but AC/DC Units are now available. 
  • To Facilitate the Measurement of Appliances and Devices, a Splitter was made that provides Openings for x1, x10, and possibly other measurements. If the x10 Opening is used, the Current on the Clamp Meter Display needs to be divided by 10 for the Actual Value read. The x10 can help on Appliances with Low Current, and for Meters with only 1 Character after the Decimal to increase the Accuracy but the Results on the Clamp Meter must be divided by 10. 
  • Splitters may have Voltage Measuring Points. 
  • Early Splitters did not carry the Ground to the Appliance, and required an Accessory to do so, newer ones carry the Ground through the Splitter and the Accessory is not Needed. 
  • Specialized Accessories were available for the Ampprobe Splitter as shown, but care must be taken when using them to fully understand how they work and to safely use them. 

Author: Dr-Artaud

A Doctor that is not a Doctor, but named after a character in the movie "No Such Thing", as is the Avatar.

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