Not only does it do exactly what it is supposed to do, but it comes with a removable terminal block to make wiring easy and it has a manual with pictures. Very well done.

Update #3 - This device is now up and working as expected, once you get it figured out, it does the job without problems. If any of you who ordered this device are having a specific problem, add a comment to this review and I will try to give you some tips.If you are the seller of this product, you can and should do a lot better job creating a user manual for it.Update #2 - Received a new unit today and was able to successfully get it up and running exactly as I had expected from the beginning.The problems I have encountered are ... 1) The labeling is not really clear so I ended up relabeling adjacent to the connector block and the control block and found that very helpful. 2) I am using this unit for intelligent monitoring of solar power by adding current parameters in addition to voltage parameters. and all the other devices I am using for this purpose including a number of sensor units accommodate AWG 16 stranded wire. This device barely accommodates AWG 16, more suited to AWG 18 or 20. 3) The flat blade screw driver needed to tighten the connections on the wiring block has to be exactly the right size to be able to tighten the connection. Otherwise to does not fit into the hole OR it is too small to wind in the retaining screw. 4) I am sure it would work fine on a DIN rail, but that makes it difficult to locate in the right spot to line up with the feed wire with the current being measured. I ended up carefully removing the red DIN slider in order to attach it with screws to the wall. Aside from those issues, I am very happy with this device. It does very clearly indicate the direction of current flow through the device.Update #1 - Mostly due to the fact that the user guide information is mostly supplied in Chinese language, I connected power to the wrong terminals and damaged the unit. But it worked well enough to demonstrate that it does a good job of monitoring current flow with a very clear arrow indicating the direction of that current flow making it easy to get that right. So at this point everything works OK except the switch itself. The red light over current and green light undercurrent work perfectly and I can track them as I see the current flow fluctuating on my own current meters. So all is good at this point except the burned out relay itself. It audibly clicks but doesn't pass actual current through the relay. Next step at this point is to purchase and install a new D633 and label it in ENGLISH before making the connections. When I do this and get th new unit it up and running I will again update this review along with a photo of the unit with the labels attached.First of all installing these things is hell, no matter what brand they happen to be. You need just the right tools such as exactly right size screw drivers etc. And the user guides are confusing. I give credit to this vender for supplying a half way decent user guide along with very useful diagrams in the description above. Most of their competitors offer much less. I have already tossed one of those in the trash. The most serious problem with this one is that this same page is used to present 13 different versions of this device. The one I purchased was a d366. A lot of you wanted the d633 and you ended up with them sending you a d630 which lacks the features you were expecting. Either you checked the wrong box when you ordered (both are blue) or Amazon screwed up and sent you the wrong one.I will be adding to this review latter after I actually get it adjusted (hopefully) and in regular service. Depending on how that goes I will either give them more stars or take a few away.

- The first one delivered did not work. The set point adjustment screw would turn infinitely in both directions without triggering the relay. The input/measured current was 8 amps.- Amazon replaced the non working one. Replacement unit seems to be working fine.- Installed the sensor relay on a vehicle to control aux headlights in concert with high-beam headlight switch. When energized: High beams on - aux lights on. High beams off - aux lights off.So far, so good.

This can be set to switch when DC current exceeds the adjustable set point and that function works correctly. However, it does not come with the delay function (there is no adjustment screw) , not as described.

I was hoping to use this to monitor for power cuts on a 240V circuit. Required function - If the monitored circuit fails, the switched contacts were to close to provide a earth / neutral connection.I have tested it, and can adjust down the monitored circuit current to very low level with the switched circuit remaining open, it also works if you turn the monitored circuit below the switched level, such as 10W, and the switched circuit closes.However, if you have zero amps on the monitored circuit, the whole device closes down, which then opens the switched circuit, so its not technically normally closed…

J'ai placé cet appareil sur l'arrivée de courant d'un tableau électrique,afin de contrôler le délestage des circuits de chauffage à accumulationdesservis par des panneaux solaires, l'intensité de courant totale des tableauxde jour et de nuit, ne devant pas dépasser 50 Ampères.Le résultat est parfait. Merci

Kontroll Led s glimmen nur sehr schwach. Kontakte schalten gar nicht. Nicht zu empfehlen

Doet wat er beloofd wordt in de beschrijvingKan gemakkelijk gebruikt worden met behulp van de duidelijke aanwijzingen die bij het item meegeleverd zijn

Het elektrische-stroom-sensing-relais werkt fantastisch. Ik heb er 2 gebruikt, ze zijn geweldig om het bewaken van elektrische verbruikers vanaf 400 mA in mijn toepassing. Het relais werkt ook bij minder, maar hierbij heb ik de elektrische stroom niet gemeten. Het relais bewaakt bij een eigen verbruik van 0,000 watt.