This is an odd device. It attaches to the side of a compatible circuit breaker, and connects to its outgoing connections. If an overvoltage or undervoltage situation occurs the device triggers and switches off the circuit breaker.
It's important to note that the unit musn't be powered continuously in a fault condition. If the power is not cut to it when it triggers, then the coil and circuitry will potentially suffer damage.
I took a guess at what the circuitry might be inside, but was completely wrong. In the true style of cost driven engineering, the circuitry is the cheapest possible.
If you enjoy these videos you can help support the channel with a dollar for coffee, cookies and random gadgets for disassembly at:-
http://www.bigclive.com/coffee.htm
This also keeps the channel independent of YouTube's advertising algorithms allowing it to be a bit more dangerous and naughty.

18 thoughts on “Over/under voltage detector – with schematic”
  1. Avataaar/Circle Created with python_avatars TheHo useholder says:

    There’s a lot of 12v breakers I’ve seen , most are being used on solar power kits for camper vans , can you check a few out please Clive as one said 200 amp and tripped at 110 amps

  2. Avataaar/Circle Created with python_avatars dirk walther says:

    Vielen Dank für das sehr gute Video! Ein toller Kanal mit genau der richtigen "Erklärungstiefe".

  3. Avataaar/Circle Created with python_avatars TRANSMITTER GUY says:

    That's the circuit they sell to the world. The circuit they (China) uses is more like you're circuit.

  4. Avataaar/Circle Created with python_avatars goata007 says:

    Can you do the video on other two devices? especially the 100amp one?

  5. Avataaar/Circle Created with python_avatars G M says:

    The YouTube picture for this video is being used on an internet advert about saving energy costs.
    I would have thought they would need permission to do this but remembered the photo of Big Clive in the Cherry Picker.
    It appears to be a difficult task looking online content.
    I for one appreciate the videos on this channel.

  6. Avataaar/Circle Created with python_avatars Moon Moon says:

    Did you know the thumbnail for this was stolen for some random ad? I would love to give a link, but YouTube will not let me share it, and I don’t know why. If you have an email address I can send it to, I’d be happy to oblige! Cheers!

  7. Avataaar/Circle Created with python_avatars Welsh Dave says:

    The thumbnail of this video has been ripped off for an advert for plug in energy bill saving device.

  8. Avataaar/Circle Created with python_avatars c4pt1n54n0 c4pt1n54n0 says:

    Just found this video's thumbnail being used in an ad online "#1 way to cut electric bill!"

  9. Avataaar/Circle Created with python_avatars Monkeh says:

    Clive, I sent you an email regarding this video.

  10. Avataaar/Circle Created with python_avatars Dant says:

    The thumbnail from this very video has been stolen and is being used to advertise scam "energy saver" products here on YouTube (capacitor in a box etc). I'm not sure if there is anything that can be done about it? Ironically it appears next to this video was well.

  11. Avataaar/Circle Created with python_avatars Steve Rojas says:

    Could you do a teardown of a cheap UPS? I recently got one and I've been wanting to know what's inside…

  12. Avataaar/Circle Created with python_avatars colin says:

    I wonder how low of voltage it would still be able to trip. Even down to 60 volts the coil should still draw 1 amp correct?

  13. Avataaar/Circle Created with python_avatars John Bond says:

    Someone's gonna hafta start 3D printing clear cases for these devices.

  14. Avataaar/Circle Created with python_avatars Grady says:

    What's the one piece of TMDE kit you'd like to have? And what's one you'd like to upgrade?

  15. Avataaar/Circle Created with python_avatars Joshua C. says:

    I found one of those digital ones that you can actually reprogram the over- or under-voltage setpoints.
    Handily it works on 230 as well as 115!
    It also has a programmable overcurrent, but it's not really meant to be used as a full-on circuit breaker – even the manufacturer recommends coupling it with isolators and real circuit breakers.
    It's rated for 63A branch, and is available in 80A branch. Since American branches are usually only about 15-20A, I grabbed the 63A model and will put it behind a 60A breaker.

  16. Avataaar/Circle Created with python_avatars Bestie says:

    Ive seen these attached to motor circuit breakers, using the mcpbs switches to turn on/off a conveyor, this trips the mcpb when the conveyor is unplugged, stopping it from auto starting on powerup

  17. Avataaar/Circle Created with python_avatars alxndr2000 | Reclusive Burgandy says:

    Clive, What's the most important individual component in a circuit you've ever seen?

  18. Avataaar/Circle Created with python_avatars aterack833 says:

    Are there any main breakers that self trip or switch off if there’s a power outage? For preventing islanding with inverters or a generator. Then you can have the inverter or whatever switch off when it detects voltage on the input side of mains, maybe a variant on the self resetting under over breaker that can work as a single space switch without needing to physically disconnect the inverter which can be connected passively through its own breaker

Leave a Reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.