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My almost-new 13-Amp electric lawnmower stopped working. I had turned it off after using it for a while to talk to someone, and after several minutes, attempted to turn it on again. To my surprise, it didn't turn on, nor make any sounds.

I had used several extension cords in sequence and noticed that one of the connections looked like this:

damaged extension cord end

Perhaps a year ago, I had replaced the other end of the extension cord in question, and suspect that the cord is faulty. When I ran my hand over the pictured female end of the extension cord, I received a slight shock. I don't believe the cord was wet, so I'm a little confused by how I made contact with a current-carrying wire, but that's beside the point.

Now, using new cords and different outlets, my lawnmower still won't operate. What kind of damage might my faulty extension cord have caused to my power tool? Is it repairable?

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  • 1
    What power tool, How many Amps (or watt) is it ?
    – knowitall
    Jun 15 at 0:54
  • 1
    Or the tool was failing and took the cord with it…
    – Jon Custer
    Jun 15 at 1:54
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    As requested by @Ruskes in a comment, it would help to know what power tool you were using, as that might indicate how much expected power draw there would be. In addition to the answer about not daisy-chaining extension cords, it's also important to note that many extension cords aren't actually capable of carrying a full 15A. Many use 16ga wiring, and are only capable of about 12A of current, max, at short distances.
    – Milwrdfan
    Jun 15 at 2:58
  • Tool failed, took cord with it most likely.
    – Kyle B
    Jun 15 at 16:30
  • it might be a fuse or one-time safety circuit in the mower that tripped. you might be able to fix it or replace the failed part.
    – dandavis
    Jun 15 at 20:19

3 Answers 3

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There are Warning signs everywhere not to use multiple power cords.

Your cord suffered current overflow leading to melting.

While the motor was running the Voltage dropped due to power cords.

Motor would have drawn more current to keep running.

Eventually the motor would burn up, from too much heat.

Let's play the game shall we ?

Your motor runs at 120 V and consumes 5 Amp = 600 Watts

Voltage drops to 110 V and the current will go up to 5.4 Amps, motor still runs

Voltage drops to 100 V and current goes up to 6 Amps, motor still runs but getting hot.

Voltage drops to 90 V current goes up to 6.6 Amp at which time the motor suffers.

That would be a 30% increase in current flow.

Evidance, molten plug on extension cord.

NEC specifies there should be no more than 5% Voltage drop from input to output. Your extension cord chain link had more than that.

Consider. replacing your burned cord with this

Southwire 2588SW0002 Outdoor Cord-12/3 SJTW Heavy Duty 3 Prong Extension Cord-for Commercial Use (50', Yellow), 50 Feet

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  • I think you are accurate in what happened, but I'd like to hear more what this means for my mower. What parts of the mower are likely damaged? Is it repairable? Jun 15 at 19:01
  • how would the motor pull in more current when the voltage is lower? An AC motor should pull less current in that situation. Only a smaller motor with an ESC would compensate for voltage fluctuations.
    – dandavis
    Jun 15 at 20:15
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That socket has given up the ghost. It's time to replace the socket.

They make field-installable replacement sockets for extension cords.

If that particular extension cord is causing an undue amount of trouble, I would look closely at its quality. Unfortunately a lot of "non-UL-listed" counterfeit/knockoff products are making it into the US market, mainly via mail-order.

If the tool was suffering low voltage due to a poor and melting connection, and you pushed the tool and ignored the groaning motor, it could have burned out the tool or burned up motor brushes.

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Question is.. how many extension cords are you running?

as stated earlier, your appliance will require certain voltage to operate ( 110v) if in US.

Its important to cover voltage transmission quick .. Voltage drops are expected when you send power across a wire ( or extension cable) -- actaully the amps (current) is what is most critical in this scenaro -- power companies actually ramp up voltage to 32 000 volts (and very low amps) so that they can transmit power across the country. then drop down again when sent to your home.

what you are doing when using lots of chords together, is loosing a few volts via the transmission (solution, get a thicker, better quality chord) your appliance is demanding a certain number of Watts ( and if you look into the power equasion (P=V/I) -- it basically menas that less volts, means more demand on amps (I) - amps is the thing that makes damage and heat so, by making the system ( the appliance and the chord) demand more amps, everything gets hotter and eventually something melts.

you would say that the circuit breaker should fix this.. but long extension cables do lots of interesting things with the effective EFI/EMI/Phonics etc.. so its not detected early enough.

TLDR: -- buy yourself a real good, thick extension that can carry the load the distance you want.

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  • Regarding is it reparable -- if your appliance has a fuse - then check that, otherwise this sounds like the first thing to break would be the motor windings -- i.e. not repariable ( at cost)
    – Hightower
    Jun 16 at 2:52

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