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Replacing Broken Cord

Woodman

Dec 3, 2012
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Hi gang,

I am trying to replace the cord on a saws-all. To test an extra cord I have laying around, I touched the two wires to the old broken wires at the points where I cut the broken cord. Well to my surprise, I got a loud pop! What would cause this?? There are only two wires (no ground) on this older sawsall. I'm pretty sure the pop occurred at the spot where I touched the second wire. I am thinking a short, but I have half the cover of saws-all off and do not see anything unusual. The cord I used to test has no polarity that I can see. Even if I reversed polarity, it still should run shouldn't it. I heard it would be unsafe if replacement cord was not hooked with correct polarity. Please help!


Woody
 
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Harald Kapp

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I assume this is a mains operated machine, right? Mains is AC, so "polarity" makes no sense.

Was the "pop" followed by a fuse blowing? This is a sure sign for a short within the machine.

Playing with mains is safety relevant. A remote diagnosis is difficult. Your best option is to get help from someone near you with the required experience.
As a second best idea, show us some pictures so someone may be able to guide you through the process of lcating the fault.
It also helps to know the model of your saw.

And last not least: whenever you manipulate something on the machine: disconnect it completely from mains befor you wotk on the machine, reconnect to mains only after your wrk is finished. In the example you have given: First connect the new cord to the machine then connect the new cord to mains. Never the other way round!
 

Woodman

Dec 3, 2012
47
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Dec 3, 2012
Messages
47
I assume this is a mains operated machine, right? Mains is AC, so "polarity" makes no sense.

Was the "pop" followed by a fuse blowing? This is a sure sign for a short within the machine.

Playing with mains is safety relevant. A remote diagnosis is difficult. Your best option is to get help from someone near you with the required experience.
As a second best idea, show us some pictures so someone may be able to guide you through the process of lcating the fault.
It also helps to know the model of your saw.

And last not least: whenever you manipulate something on the machine: disconnect it completely from mains befor you wotk on the machine, reconnect to mains only after your wrk is finished. In the example you have given: First connect the new cord to the machine then connect the new cord to mains. Never the other way round!

Thank you Harold for the excellent reply. Yes, this is an AC tool. There was no fuse that blew. I may have prevented fuse box blowing by just tapping test cord for a millisecond and pulling back. I decided to cut bad part off old cord and reuse it. This worked and tool seems to be working like a charm. The quick-lok cord no longer locks though and yes I know it is not as safe now, but anyone who knows anything about these damn cords agrees they are a pain cause they fail so frequently. I still am baffled as to why I got that pop, or short. Possibly the way I rigged up the saws-all when I wanted to test the other cord (I put clamp on the trigger to hold it down, and then attached/touched/zapped the new cord)?

By the way this is an older model Milwaukee Sawsall Model #6521-21 with 2 prongs and double insulated.
 
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adamq

Dec 17, 2013
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Dec 17, 2013
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Woodman, are you sure the stranded conductors didn't fray and possibly touch one another?

As mentioned, this sounds like a short, either within the saw or within the new or old power cable.

Also, what Harald means by "I assume this is a mains operated machine, right? Mains is AC, so "polarity" makes no sense" is that the "neutral" on a mains line/wall receptacle is ultimately grounded.

The only conductor with power on a mains receptacle "hot" (narrower of the two) which is AC power. I know it's often referred to as + / - but that's a misnomer.

Check out http://science.howstuffworks.com/electricity8.htm if you're curious as to the difference.
 

adamq

Dec 17, 2013
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Possibly the way I rigged up the saws-all when I wanted to test the other cord (I put clamp on the trigger to hold it down, and then attached/touched/zapped the new cord)?

Yes, that would do it. You manually connected live wires to a completed circuit (trigger depressed): not unlike arc welding.

Again, the order of which you do things makes a difference:

First unplug everything.
Then repair the wire.
Then plug to mains.
Circuit is not complete til trigger is pressed and power reaches the motor.
THEN test the trigger.
 

Woodman

Dec 3, 2012
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Yes, that would do it. You manually connected live wires to a completed circuit (trigger depressed): not unlike arc welding.

Again, the order of which you do things makes a difference:

First unplug everything.
Then repair the wire.
Then plug to mains.
Circuit is not complete til trigger is pressed and power reaches the motor.
THEN test the trigger.


Wow - Arc Welding !! Holy Shite - that is Awesome dude !!! Who New !!!!
 

Six_Shooter

Nov 16, 2012
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AC cord replacement is not difficult, but the way you tested is very dangerous.

Most AC cords I have seen for tools will have a white and a black wire inside the outer cover. I use this a guide when I remove the old cord from the device and ensure I connect the new cord in the same way, put the black where the black was and the white where the white was.

If there is no coloured indication then use your best descretion, as AC does not have a polarity, but some devices will have one conductor attached to certain parts internally, that may make the tool more dangerous in certain situations, due to how the live and neutral wires are connected through other devices.

As suggested, getting someone that has experience to do it or guide you would be the best bet.
 

Woodman

Dec 3, 2012
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Dec 3, 2012
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AC cord replacement is not difficult, but the way you tested is very dangerous.

Most AC cords I have seen for tools will have a white and a black wire inside the outer cover. I use this a guide when I remove the old cord from the device and ensure I connect the new cord in the same way, put the black where the black was and the white where the white was.

If there is no coloured indication then use your best descretion, as AC does not have a polarity, but some devices will have one conductor attached to certain parts internally, that may make the tool more dangerous in certain situations, due to how the live and neutral wires are connected through other devices.

As suggested, getting someone that has experience to do it or guide you would be the best bet.


Six_Shooter, thanks. Yes I did the white to white, black to black thing (I think). Can you give a dangerous example/situation? As stated, this tool has two prongs and is double insulated whatever that means. Thanks.

Woody
 

Woodman

Dec 3, 2012
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Dec 3, 2012
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No kidding! I always wanted to do some arc welding, albeit under safer conditions.

I may have to pry apart that quick-lok cord again and trace the wire coloring to make sure they match.

Thanks everybody - I love coming here and finding out how ignorant I really am about AC mains power.

Lesson Learned ? -- 1.Don't plug in cords that have the other female end removed, and then 2.Hook dangling live wires up to complete a circuit.

It may work, but is the not the "enlightened" way, and as I can attest too, is foolishly dangerous. Correct way,as stated previously twice, is make the cord repair and then test tool. I gotta stop messing with AC mains - that juice has got me more than once and could be my demise.
 
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(*steve*)

¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd
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Jan 21, 2010
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I'm not sure how serious you're being, but we have people coming here with widely ranging levels of experience and common sense.

We tend to be fairly conservative with advice that can put people at risk. We'd hate for someone to make their last mistake.
 
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