Customer Reviews
This is awesome! 
2008-08-05
Ok, not only is this a Fluke meter (which happen to be the best meters out there!), it also has a great clamp that keeps it where you want it to be! It is an awesome idea, and something I would recommend to anyone!
Great Product 2008-04-29
It works very good, I recommend this Clamp meter for home and also industrial jobs, FLUKE is and excellent brand.
A big step up from the 30 series fluke amp clamps 2008-04-21
I own and operate a test laboratory and frequently need accurate and dependable measurements where time is money. The fluke 337 is the top of the line AC/DC amp clamp + meter and quickly gives me information that is accurate and repeatable.
Here are some spec's not posted in the literature.
For voltage, the input impedance is 1.0 Megohm instead of the more common 10.0 Megohms in DVMs today. Some accessories (particularly thermometers and high voltage probes) depend on a meter having a 10 megohm input impedance, so they may not work correctly on the 337 and should be used with a "normal" DVM and not the volts/ohms input on the 337 amp clamp.
The 337 is a pleasure to use with a one button "ZERO". When measuring DC current you must zero out stray magnetic fields, including the earth's, to get accurate readings.
Prior to the 337 this was done with a knob on the front which you twisted to get a 0.0 reading. After years of use that knob got worn out.
With the 337, you simply press the zero button before making the measurement, then clamp the jaws aroud ONE conductor to measure.
It has min/max record as well as inrush current measurement ability as the top of the line in the 33x series of amp clamps. This gives you the ability to measure DC as well as AC currents, inrush current, and have a measure hold button on the side.
It also had 4 LEDs (green) which backlight the display when needed.
Instead of using 9V batteries, like its predicessors, it operates off 2 common AA batteries (rechargable, alkaline, or lithium primary cells) which is a pleasure given the price difference in 9V cells and AA batteries. The meter uses about 10 mA from the batteries, so two lithium batteries should run it for 300 hours or 10 years whichever comes first. There is also an automatic power off feature if you forget to turn it off.
Ohms measurment features a beeper for continuity however stops around 1000 ohms while most DVM-only designs go up to megohms or more. Again, this unit is good for checking circuit continuity and wire resistance but not suitable for a wide range of engineering where a normal bench DVM will be needed for larger resistance measurements.
Using any amp-clamp meter requires that you only run a single wire of a 2 wire (or more) circuit through the clamp at one time to determine the current in that wire. If 2 wires go through the clamp they add or subtract from the total measured making the reading useless or 0.0 For example, to measure the amps required to run your car starter, pick one of the heavy wires at the car battery (it doesn't matter which since the current goes through both the positive and negative). Next set the meter for DC amps since this is a battery powered circuit. Press the Zero button to zero the display. Clamp around one wire at the battery, press the min/max record since you'll be inside starting the engine, then go inside the car and start the engine. When you return to the meter, the maximum current drawn will be your starter's cranking amps. You'll also see a negative current for the minimum - this is your alternator recharging the battery after starting the engine. The reason it is negative is the power is returning to the battery. With one tool you have tested your starter, alternator, battery, and a good portion of your vehicle's electrical system, and done it without a wrench or screwdriver or disconnecting anything! Using the leads, you can measure battery voltage, check for blown light bulbs, and other common tasks.
AC current measurements are easier as they do not require the zero button.
I also own the fluke 410 current clamp but use it with oscilloscopes for more detailed information. The 337 is easier to use than the 410.
In summary, having a basic AC/DC volt-ohm meter and current clamp in one package with all the advanced display functions is a great tool. The only mistake you can make is running more than one wire through the clamp. Special adapters are made to get around this (such as measuring the current used by an AC device with a single power cord containing 3 wires) - they slip between the outlet and the device and have a plastic frame that goes over the clamp to carry the current through the clamp.
If you NEVER expect to work on DC circuits (cars, boats, solar, etc) then the fluke T5 AC meter is a good alternative. It is smaller than the 337, simpler to use, but lacks the min/max record, the DC amps, inrush, but has a neat "fork" design to go around a single AC conductor that does not need to be closed like the clamp does. It is a useful electrician's alternative to the 337. The T5 comes in both 600 and 1000 volt versions depending on your needs. Fluke T5-1000USA,Electic Tester 1000V,Continuity,
