Martindale Electric NC4 Dual Sensitivity Voltage Tester, Volt Stick with Torch, Circuit Tester

I volunteer at a repair cafe and this little marvel as been a game changer for tracing electrical faults. It detects current flow and helps identify what components are working or not working without having to dismantle the whole thing.

I was looking at getting the Fluke 2AC/90-1000V but found that it does not have an audible alert and the LED isn't great in bright light. I looked at the 1AC-II which has an audible alert, however the UK version is only 200-1000V. Ignore UK suppliers advertising the 90-1000V, you'll receive the UK 200-1000V model. I wanted to have a non-contact tester that would indicate lower voltages such as 110V. Having recently bought the Martindale VT12 Voltage Tester and found it to be very good (see my review) I took a punt on the Martindale NC4 as a companion device. The NC4 has two sensitivity ranges 12-1000V AC (not DC) and 50-1000V AC with a nice audible alert and flashing red LED when it detects my 240V domestic supply (I don't have anything lower in AC to test). It also has a handy LED torch function. When you first switch on the NC4 the bright red LED flashes once a second to indicate that it is in the 50-1000V range. Briefly pressing the button again switches to the 12-1000V range and the red LED flashes twice in one second. Turn off the NC4 by pressing the green button for 2 seconds or it will eventfully auto-power off. I did a 240V test of how well it works where there are three wires in close proximity. I cut the end off a cable exposing the Live/Neutral/Earth to a length as you would when fitting a UK plug. I then plugged the other end into 240V so making one of the three exposed wires live with the other two dead cables close to the Live. In the 50-1000V range the NC4 probe had to be approximately within 3mm of Live for it to alert, it did not alert when placed near the other cables even though they are close to the Live. In tight spaces it is unlikely that you will get false positives from cables that are not live when they are close to a Live. That is an excellent result, I've read reviews where these devices are far too sensitive and pick up so-called "live" cables when in fact they are picking up the Live from one close-by. I much prefer to be almost touching the Live cable, the probe is long and suited for this very purpose. In the 12-1000V range you merely have to be within 50mm of the cable for it to detect Live, handy for checking thicker cables and wall/light sockets (it isn't sensitive enough to detect cables within walls). You'd also use this when waving it around to find a Live cable and then you'd switch to 50-1000V to focus in onto the individual Live cable. As with any device there is the odd gotcha with these things that can trip you up: When using a non-contact tester it is important to know that when testing cables you should move the probe all around the circumference and up and down the length of the cable as the Earth cable could be blocking the detection of the Live in a twisted core. You should of course test the device on a known Live before use (and after use if it didn't find anything as it could be faulty!). As with any device of this nature (like neon screwdrivers) you should NEVER use it to test for dead. These devices are not reliable enough to put your life at risk, in a tight space these devices can easily be fooled if the Earth wire is blocking the Live wire. Use with caution and know the limitations of your kit. If you must rely on a device for testing for dead then a Martindale VT12 is absolutely what you should be using. I can not stress the importance of using a VT12 to test for dead and not one of these non-contact devices, or you might be dead yourself!

It's pretty good, and I like that it has a light and 2 sensitivity settings, but it's still too sensitive! If for example youre testing which brown is your feed at a switch this will just beeb away once youre near it, making it difficult to tell whats live and whats just a switch wire, making the 2 sensitivity settings kind of redundant! This does however make it more reliable than my old Fluke pen at testing whether a circuit is actually live or not so I would put more trust in this device than the fluke for that purpose although you should never assume a circuit is dead, but better for example at testing sockets at the face rather than having to open it up! Good, but i wish sensitivity was refined more, or better yet adjustable with variable resistors inside the casing!

Works as it should!

Works very well for testing live electricity

Not for professional use but its an additional precaution when doing minor jobs around electrical devices. Worth the money as a safety measure.

Seems fine for now, just bought it. The old model was a better grip in the hand and the power button worked instantly; the new model is a bit annoying in that the end continually flashes when on and you need to press for a second or two to power off. Still a useful tool, not too sensitive so can work quite close to see where current is, though I would say 1 cm is about it then it gets confused as to where the current is and you have to poke about a bit with the end to work out which wire has current eg in a box.

Everyone who gets involved with potentially live wiring should have one of these. Few tips on use: Prove before and after use (easy to see it is on - but still essential to prove it is functioning). With cable or flex it is possible for the earth conductor to shield the live conductor. You can demonstrate this by running the detector along a flex where inside the wires are twisted into a helix. The detection will go off and on. Easy to remove this risk by running the probe around the flex or cable and not just at one spot. In the video the three core white cable is "live" with 240V. The twisted individual cores are simulating why the signal drops out periodically due to shielding.

Très pratique pour les interventions urgentes lorsque il s'agit de vérifier la présence de courant sans utiliser un multimètre.