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Usually my laptop charger is working fine. However, today I switched on my laptop charger as usual and suddenly the main box circuit breaker tripped.

I plugged the charger into other sockets: same result.

May I know what's the reason for this? Has the charger died?

  • 5
    Can you clarify whether what trips in the main box is a standard breaker or a GFCI breaker (one designed to trip due to a grounding fault, which may have a built-in test button)? And you've verified that it is actually a main box breaker that's tripping, rather than a GFCI outlet that may be on the same circuit as your wall outlets? This just seems like an unusual failure mode for a laptop charger unless there is something like a short in the power cord, in which case, you should be aware of burning (smell, heat, charring, arcing). – fixer1234 Jul 15 '16 at 8:49
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    Yes, please clarify what exactly is tripping. The answers would probably be similar if not identical, but the implications are different. – a CVn Jul 15 '16 at 9:00
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    Is the laptop connected by wire to anything other than the charger? Is there an Ethernet cable or a video cable? If so, can you replicate the problem with the laptop disconnected from these other things? The problem may not be the charger. Also what type of circuit breaker is this? Is it an old-style overcurrent only? GFCI? AFCI? – David Schwartz Jul 15 '16 at 10:52
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    Also, were the circuits in question in use by other devices already? E.g.: If, on a 15A circuit, 14A continuous was already present, adding 2A would be more than sufficient to trip the breaker. Give us a little more context on the situation. – kronenpj Jul 15 '16 at 12:21
  • You state that you checked charger on other sockets but can you confirm that those other sockets are on a different circuit (trip a different breaker) or did the other sockets trip the same breaker? – nvuono Jul 15 '16 at 19:57
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Get rid of it at once.

Standard amp draw for a circuit breaker is 20A or more (check your breakers for the exact number, it is printed on). Your power supply should not be drawing anywhere near this much.

That much current probably means it failed to a short circuit. 120V * 20A[lower limit of current draw] = 2400 watts. That's a minimum of 2.4x what a typical microwave puts out. Your charger will get hot enough to start a fire.

EDIT:

Mark in his answer makes the point that it might be a combination of devices operating normally which together exceed the load on the circuit. While this is a valid point, most chargers will draw < 2A. That means that the circuit must, in its normal operation, draw very close to the maximum current draw permissible. More than likely, if this were the case, the OP would have a history of breaker trips on this circuit with startup power surges. Also, the OP tested on multiple sockets, which may (OP clarification wanted) mean that the OP tested on multiple circuits.

Easy test: plug in another appliance with similar current draw in one of the same plugs. If it doesn't trip, then it's not the cumulative current draw.

Conclusion:

Yes, there are possibilities other than a failure to short, if you fancy experimenting to see if the charger OK. However, laptop chargers cost $30 (approx). Electrical fires and hospital bills cost a lot more.

  • 7
    Not only "Your charger will get hot enough to start a fire", but also it's entirely possible that it did get hot enough to damage some internal circuitry before the breaker tripped, and entirely possible that continuing to try to use it with the laptop will result in damage to the laptop (if it hasn't already). Definitely a "get rid of it at once" situation. – aroth Jul 15 '16 at 4:36
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    -1 There are different voltages in the world. – Max Ried Jul 15 '16 at 9:40
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    @MaxRied But not so much different that it invalidates the argument. In Europe (especially Germany) you have 230 V and a standard breaker value of 16 A, which makes even 3680 W. – glglgl Jul 15 '16 at 10:08
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    If the charger tripped a breaker on overcurrent then I would expect it to be pretty obvious - something in that charger would be smoking and the smell of burnt electronics would be immediately obvious. The likelier scenario is as others have suggested - that the circuit or main panel has ground or arc fault protection and that one of those safety devices is activating before the fault has a chance to built significant current draw. If so, "get rid of it" is still the right answer, of course, but plugging it into a socket without such protection might result in a much more dramatic failure. – J... Jul 15 '16 at 11:10
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    @Agent_L OP tried other appliances in the same sockets without issue. OP also tried the device in other sockets with the same result. So... that eliminates the faulty breaker possibility and the faulty socket possibility. OP didn't say they were using an extension cord either, so... – J... Jul 15 '16 at 21:13
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More than likely. If the charger is consistently causing the breaker switch to trip, then it is probably fried. Dispose of it and purchase a replacement.

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    yes! if the charger activates the breaker and an ordinary load like a toaster, hair-dryer, or electric jug does not, the charger is defective. – Jasen Jul 15 '16 at 9:19
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A gaming size laptop might have a 45Watt supply which might be able to briefly generate 200Watts of power demand at startup. That's enough to overload a magnetic circuit breaker if you have 2200 watts of demand from other devices on the circuit like say an air-conditioner and a microwave oven. I wouldn't connect it to the computer side again without seeing if you can make the power supply blow the circuit again with no load. If not you might want to build a test lamp out of a lamp socket and a 200watt 120VAC floodlamp. Then comes the hard part of measuring the power supply output with an inexpensive DVM meter - a large computer might require from 17 to 19Volts DC. If that matches what it says on the power supply label you probably can safely plug it back in to the computer, try it and declare the event a glitch. If everything works. Amazon has a lot of New replacement OEM power supplies if need be.

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    This should really be part of any accepted answer. Simply connecting and getting a fault means nothing. It is important to also figure out why it's happening, although constantly connecting it might not be the best/safest approach. – William Mariager Jul 15 '16 at 7:33
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    I've seen >100W constant rated laptop supplies for old laptops (or universal spares). But they shouldn't be able to draw enough current to trip a breaker suddenly even if it's already overloaded (a dead short is the only thing that will trip it quickly, overcurrent will take seconds to minutes). Earth-leakage breakers also trip instantly when they go. – Chris H Jul 15 '16 at 8:10
  • my less than gaming size laptop (Lenovo Y70 touch) has a 135W power brick (lenovo says gaming, but several review say otherwise) – Jasen Jul 15 '16 at 9:15
  • OP states: " I checked charger on other sockets same result happen" – hexafraction Jul 15 '16 at 11:39
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    Gaming laptops will have much higher than 45W. The max I've ever seen is my old Dell Mobile Precision, which is 240W. – chrylis Jul 15 '16 at 21:45
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Is it tripping the circuit-breaker, or is it tripping the Residual Current Device (RCD)? the latter typically has a TEST button and a rating in mA. More likely there's a small earth fault with your charger/lead.

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    Sounds like a QUESTION for the Home Improvement community. – Pimp Juice IT Jul 15 '16 at 5:17
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    True, but the outcome in each case is the same: if the cause of tripping has been confirmed as the charger or lead and not a faulty socket, coincidence, etc, then it needs to be scrapped and replaced. – nekomatic Jul 15 '16 at 10:01
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One more possibility: Does your laptop charger have a Linetek LS-15 cable attached to it?

If the cord was made between mid-2010 and mid-2012, chances are good it's affected by a recall, which was due to a defect causing a possible internal short in the cable and a fire hazard. This, too can cause the adapter to trip the circuit breaker.

If your AC adapter's power cable is affected, contact your system's manufacturer to get a replacement.

  • This may also be the case if the AC power cord isn't that cable, or isn't from those years. (Recalls identify a systemic problem, if I'm not mistaken; the absence of a recall doesn't preclude the possibility of isolated or occasional problems.) Also, AC power cords (the one running from the wall into the AC adapter) should be available from third parties. Look for one that's been approved by Underwriter Laboratories or equivalent. How to safely determine whether it's the AC power cord, I'm not sure. – Mathieu K. Jul 16 '16 at 5:43
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DO NOT "Throw the switch" !!!

click on the picture
Click on the picture for the youtube video...

Short-circuit

Your charger is making a "short circuit" do not plug it again if you really don't know what you are doing.

A short circuit[2] is an abnormal connection between two nodes of an electric circuit intended to be at different voltages. This results in an excessive electric current limited only by the Thévenin equivalent resistance of the rest of the network and potentially causes circuit damage, overheating, fire or explosion. Although usually the result of a fault, there are cases where short circuits are caused intentionally, for example, for the purpose of voltage-sensing crowbar circuit protectors.

The charger circuit it is not complicated per se. The problem is the voltage and amperage of the home net: note that in some language the breaker is called "safe-life". At the risk reported above by wikipedia, there is the electrocution. You can burn all the cable between the plug and the main switch.

The most probable case is that your charger is gone and you have to buy a new one.

If you are lucky, and it is not yet gone, the causes can be:

  • The cable. In some models it's possible to substitute it plus or less easily[b,c].. In some other it is needed to have some expertise or to go to a technician.
  • Some internal part. With high probability the circuit protection [cp]. enter image description here

    Even if the components are not expensive, without training it is really not the case to operate by yourself. enter image description here

  • Short circuit is only one of many reasons that can trip circuit breaker. Your assumption may or may not be correct. – Agent_L Jul 15 '16 at 14:04
  • @Agent_L The circuit breaker is triggered by an excess of current. I suppose you agree. Once you exclude the home/office network is at its limit (the OP states that he plugs the charger as usual = in normal conditions), that you exclude that there is a defective socket, since the OP has done other times (it means the socket worked) and the OP reproduces the same problem from a different socket too (I assume a working one)... what else it remains? Maybe I miss something :-) Moreover, if the cable is defective and two wires enter in contact, it's a short. A fused capacitor trigs SCR?SC too. – Hastur Jul 15 '16 at 14:51
  • When connecting a capacitive load, short excessive current is normal and should not trip the breaker. Breakers have small delay exactly to withstand that. A breaker can be faulty by acting too fast, which will not manifest with resistive loads and even with other capacitive loads who stay connected permanently (like a microwave oven) so they stay charged. Also, it might be a ground fault breaker which detects not a fault in the psu itself, but eg a laptop being connected to other device with damaged insulation (eg a powered USB hub with faulty +5V PSU) – Agent_L Jul 15 '16 at 15:00
  • @Agent_L The USB hub with faulty ground is again a short_(that will fall on the laptop first and should remain there -- the protection of the usb circuit of the MB should act faster then each propagation to the external net, turning off the laptop). BTW The OP checked the charger in another socket (with no mention to the laptop and to any device connected to). This, with the fact that usually it works, IMO exclude any excess of current caused by the connection of a _capacitive load (modest if you consider the whole capacity of a domestic net). I tried to fit the answer to the OP question. – Hastur Jul 15 '16 at 15:49
  • It can be a faulty breaker just as well. BTW, there is no protection on the MB that can stop anything at mains level without tripping the breaker. The kind of fault I described can send current on the ground plane only, so it's not even detectable by the equipment. – Agent_L Jul 15 '16 at 15:58
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The breaker cuts off when the current through it exceed nominal value at nominal temperature. If cold it breaks slightly later, in hot slightly earlier. That's how it works. That means you have oveloaded the net.

You can overload it by using power demanding devices at once - for example fridge is on, micorwave is on, washer is on and you connect the laptop. Every single device does not exceed the limit in total they overload the circuit and may start the wires start the fire.

The circuit may be overloaded also by switching on transformer or asynchronous engine. For short ammount of time they may be considered as a short-circuit and may lead to breaker cutoff.

There is actual short-circuit and this faulty connection may start the fire.

As I understand your question, the first two options are out - You plug in your charger as usual and it suddenly fails.

Taking possible costs to account, dispose the charger as soon as possible and buy a new one. The transformer inside probably got burnt. Or you prefer buing new laptop or paying off the fire?

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