Clamp-On Current Meter Readings

dclark1946 wrote:
I use both an Extech 40/400 A true rms clamp on and a Sears combined DC clamp on /multimeter. The Extech has a zero function and will resolve down to 10 mA and the lower cost Sears unit will not resolve down as low but it also has a zero function. These units are pretty accurate. You are smart to add this type of meter to assist in monitoring maintaining your 12V system.

Dick

X2. And for RV work and many other jobs these meters are more than perfectly adequate. They are accurate enough, rugged enough and low enough cost and will last a long time with any reasonable care.

What we need are "qualitative" readings, that is Is current flowing? Is it close to what I expect? does it make sense. Not necessarily "quantitative" readings. E.g. 3.0004A, exact, accurate, highly repeatable readings.

there area a few cases when DC Volts accuracy is more important, for example determining battery state of charge. There DC accuracy to .1V DC is pretty much necessary. But with today's DMM's that is pretty much achievable at reasonable cost.

I have a NBS traceable certified DMM and AC and DC current probes. They stay in a good case and get pulled out on the very few occasions I need them.

For virtually everything else, I have a very rugged reasonably accurate, reasonably repeatable DMM and AC and DC current meters. In 99% of the cases, they will tell me what I need to know with enough accuracy to determine what I'm looking for.

Only thing else that would be REAL handy on occasion would be a inexpensive 4 terminal ohm meter with long leads. resolution down to .1 milliohm or so, full scale of maybe 10 ohms.

One of my DMM's comes close, 50 ohm scale that you zero by shorting the leads together and it reads to 0.01ohms (10 milliohms) but it isn't all that repeatable for zeroing. but it is handy for finding bad connections.