Pardon my dumbness, but I thought that the " clamp end " of a clamp meter could be used to measure voltage of a 12 volt wire without cutting or penetrating the cover.
That is, open the clamp and close it over the insulated wire and get a reading. O, then has stopped pumpingr on an expensive instrument actually encircle said wire and still get the reading.
My impulse buy economy version will not do this. It is quite accurate with the probe ends, have tested on two separate items and all good.
I want to test the van water pump prior to removal. They screwed it to the floor, put the water fittings on and then put the oven over the top, so quite a task to remove.
Water pump was very noisy, but pumping ok, then has stopped pumping, but can hear a quiet noise with switch on. So want to eliminate voltage drop as a reason for no pumping.
And just in case you are not using it correctly ....
When you say "open the clamp and close over the insulated wire", the clamp should encircle the wire, not grip the wire like pliers. I think your next sentence shows that you know this but I could not work out exactly what you meant to say. Also, it should only be placed around one wire in the cable.... either the positive or negative. Not the whole cable. The direction of current flow will usually be marked on the jaws, but if placed the wrong way, most will display a negative value.
Ok, on my 12v pump I have tried it on both single wires, encircling it, but get no reading. So presumably a faulty cheap item. The jaws have volt limits stamped on the front side only.
On other appliances it has been a twin wire, or enclosed with outer sheath, so that is no good for a read then.
The clamp end of the meter just measures current flowing inside the circle of the jaws. One wire only at a time. They are not particularly accurate either at low currents, but easy to get quick readings. For voltage use the probes and leads plugged into the sockets on the meter!
It is most likely automatic polarity reading so not important which way round the leads or the clamps are used. So if you look for the + or - on the display, if it is -ve then just backwards, no problem. Jaahn
-- Edited by Jaahn on Saturday 25th of November 2023 06:51:22 PM
Whenever I need to check a 12 volt supply wire and/or negative/earth wire in situations such as Craig1 described, I push sewing needles into the wires (they don't need to go the whole way through) and then I use a regular multimeter.
Theres 2 types of clamp meters, ones that read AC/DC amps & others that read AC amps only. So if you got an AC only then it wont read DC current. They also usualy the cheapest.
The supplier, who is appearing to somewhat of a conman, insists it does 12v and was " tested " prior to shipping. They also claim to have sent a replacement, but to my " ebay " address " (after offering a $7 refund, then upped it to $10 ) so still giving benifit of the doubt, but thinking I need to get the pump replaced. Testing was just a vain hope.
