# Low amps kills skill saw?



## Bill (Mar 30, 2006)

Am framing a house. Its an addition. Breakers seem to make a "Sizzle" noise after about 6 hours of use. My skill saw will not run now. Can this be a result of inadequate amps running the saw?


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## CE1 (Dec 30, 2005)

USP45 said:


> Am framing a house. Its an addition. Breakers seem to make a "Sizzle" noise after about 6 hours of use. My skill saw will not run now. Can this be a result of inadequate amps running the saw?


low voltage and high amps was your probable problem. How long and what size was the extension cord you were using? A shorter and larger sized extension cord would of been better.

Someone will come along with a extension cord sizing chart.:whistling


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## Bill (Mar 30, 2006)

Could had been. We use a extension no longer than 10 foot and very heavy gauge for the compressor, the skill saw was plugged into probably a 50' cord from Lowe's (Home Owners)


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## mdshunk (Mar 13, 2005)

USP45 said:


> ...the skill saw was plugged into probably a 50' cord from Lowe's (Home Owners)


That'll do it every time. Voltage drop kills saws. Run really heavy cords for your saws. It seems silly, I know, to spend 100 bucks on a 50 foot extension cord, but you really need to. Probably should have been a 10 guage cord for that length, but the homeowner's cord was more than likely 16 gauge.


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## MALCO.New.York (Feb 27, 2008)

This might help.

http://nevadawalrus.com/index-wired.html


As it has been posted in other threads...ALWAYS over gauge and over rate the load you have. One can NEVER go wrong that way!!

And when your work site begins to resemble this...










then it is time to reevaluate!



This is next............When you ignore proper load!


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## Bill (Mar 30, 2006)

mdshunk said:


> That'll do it every time. Voltage drop kills saws. Run really heavy cords for your saws. It seems silly, I know, to spend 100 bucks on a 50 foot extension cord, but you really need to. Probably should have been a 10 guage cord for that length, but the homeowner's cord was more than likely 16 gauge.


Would not doubt the 16 gauge. I left mine home, so the HO said we could use his.


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## mdshunk (Mar 13, 2005)

USP45 said:


> Would not doubt the 16 gauge. I left mine home, so the HO said we could use his.


Oh, by the way, in case you were wondering.... your saw will never be the same. Keep your eyes peeled for a replacement.


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## Bill (Mar 30, 2006)

I am MD, I am going to buy a new one. Figure its cheaper and faster.


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## mdshunk (Mar 13, 2005)

I often thought I could build a little box for pretty cheap that would just shut the power off if there was too much voltage drop, but I doubt anyone would buy it. The saw manufacturers could make a pretty small circuit to put in the saw's handle to shut off the power and preserve the saw, but it would probably just tick people off. A few cuts with extreme voltage drop is no big deal. Working all day is a pretty big deal.


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## MALCO.New.York (Feb 27, 2008)

mdshunk said:


> The saw manufacturers could make a pretty small circuit to put in the saw's handle to shut off the power and preserve the saw, but it would probably just tick people off.


But how would this benefit the repurchase factor.

Kinda like GM could make a car that lasted 3 million miles and a carburetor/detonation configuration that allowed 200 MPG.

It is all about the bottom line.


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## plumberman (Jul 14, 2008)

MALCO.New.York said:


> This might help.
> 
> http://nevadawalrus.com/index-wired.html
> 
> ...


 
That first pic looks like a still shot out of "I AM Legend"


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## MALCO.New.York (Feb 27, 2008)

plumberman said:


> That first pic looks like a still shot out of "I AM Legend"


Google images.


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## neolitic (Apr 20, 2006)

MALCO.New.York said:


> Google images.


Or...
http://www.linein.org/blog/wp-content/gallery/bad-wiring/353206250_6eb6a7cd1c_o.jpg


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## jrclen (Jul 10, 2007)

I ran into a good one. I was about to drill the studs on the second floor. I found a heavy duty cord already hanging up there. It had a 20 amp 120 volt connector body on it. Lucky me.

I plugged in my short extension cord and drill and squeezed the trigger. Fire shot out of the drill and it made a noise and smell that is very hard to miss. Seems that cord was wired into the panel for 240 volts for a large barn fan the carpenters had up there in the heat. 

The new drill had less than 2 hours on it when I did this. It is still working fine on 120 volts thank goodness. Why would they use the proper connector body and plug? They knew not to plug their saws into that cord. :furious:


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## Splinter (Apr 5, 2005)

> I ran into a good one.


John, I had a similar thing happen... Homeowner had an AC unit in a window. My boss (at the time) unplugged the cord and plugged in his shop vac. It was a regular 15A 120v outlet afterall. Boy did that vacuum scream! Homeowner had it wired for 220v, and my boss didnt really notice the replacement plug on the AC's power cord. That vacuum still worked for the next 3 years while I worked for him. Hell, it could still be working today!:thumbup:


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## jrclen (Jul 10, 2007)

Splinter said:


> John, I had a similar thing happen...


Well I'm glad I'm not the only one. :clap:


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## Electric_Light (Nov 25, 2007)

A cord someone has sitting around is usually 16AWG, if not 18. 50' extension cord for running a circular saw on 120v should be 12AWG.


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## A W Smith (Oct 14, 2007)

Two things that will kill saws guaranteed. low amps. dull blades.


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## Splinter (Apr 5, 2005)

Kills compressors too... Customers home had a lot of DIY wiring... I plugged the trailers compressor into the garage outlet with my heavy duty cord and it ran sluggish... We were so busy and I just wanted to get this job done, so I left it as is... Second day the compressor burned out. Turns out that garage outlet was at the end of an almost 400' run of 14-2 romex. Half the house was on that circuit.


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## Cole82 (Nov 22, 2008)

Is there a way to check the outlet for proper amps? I burned upa a saw a couple weeks ago at a customers house. Is the safest way to just use the generator for every thing?


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## Kent Whitten (Mar 24, 2006)

OK, I'm no electrician, and I know enough to hurt myself. I would like to see the skil saw you are using. To toast it, I would think you would really have to hog it down, severely not pay attention to your equipment saying "WTF, stop, you're killing me!", your saw was already on it's last legs.....something.

6 hours and the breaker is sizzling? Something must have been going on during this 6 hours for you to say "huh....that's weird..." anything, something...

I have run my skil saw on a 100' 12 ga. for years and you can hear it bog down on low amperage. If you are burning it, you should at least smell something, or your breaker is bigger than it should be to keep it from tripping.....something. You've got something messed up somewhere whether it's the user (no offense meant) or the breaker or the saw/cord.

I realize low amps willburn it out in no time, but there must have been a warning sign of something. Your saw start really slow? kind of lethargic? low power?


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## dlcj (Oct 1, 2007)

I agree with you framerman. I can almost tell you how long and what size cord im plugged into (if i didn't already know) when i pull the trigger on my dewalt 15 amp saw.
I try to use only a 50' 12 ga with my saw. On a big house job we have a 100' 10ga with a 4 plug box on end that we pull from sevice pole to house. Plug mitre saw directly into that and 50' 12 ga to skill saw and smaller longer cords to other tools under 15 amp draw. 
I was working at a place one time and my set up was 120' from the nearest plug. A guy that worked there was helping me and when the 100 16ga cord (his) he pulled was not long enough he got another 100 16 ga and brought it the rest. NOT!!! Told him to get out my 2-50' 12 ga and one 50 14 ga. I didn't have my 10ga with me that day. He didn't understand


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## jrclen (Jul 10, 2007)

Cole82 said:


> Is there a way to check the outlet for proper amps? I burned upa a saw a couple weeks ago at a customers house. Is the safest way to just use the generator for every thing?


The problem is low volts, not low amps. The voltage of a circuit can be checked with a volt meter while the circuit is under load. Measuring the voltage without a load is meaningless.


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## Cole82 (Nov 22, 2008)

jrclen said:


> The problem is low volts, not low amps. The voltage of a circuit can be checked with a volt meter while the circuit is under load. Measuring the voltage without a load is meaningless.


I don't know a whole lot about the electric side of our industry.
So does it have voltage drop over distance? What would be the volt cut off where I shouldn't run my $500 chop saw? Just trying to prevent anothe costly mess up.


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## pudge565 (Jan 26, 2008)

The imax recommended voltage drop is 3%. So if the voltage is 120v you can go down by 120*0.03=3.6v so the lowest RECOMMENDED voltage drop is 3.6v.

If you hae 240v the max is 240*0.03=7.2v


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## jrclen (Jul 10, 2007)

Cole82 said:


> I don't know a whole lot about the electric side of our industry.
> So does it have voltage drop over distance? What would be the volt cut off where I shouldn't run my $500 chop saw? Just trying to prevent anothe costly mess up.


Voltage drop is dependent on the distance and the load. And can be fixed by using a larger size wire. Most 120 volt power tools would have no problem with around 110 to 128 volts. You could check with the manufacturer on your particular chop saw.

Just keep in mind if you check a receptacle or cord with a volt meter, the reading will vary with the load. So if you stick the voltmeter in the end of the cord with no load you might see 120 volts. Turn on the saw and cut a 2x4 and that voltage could drop by quite a bit.

Bottom line is, bigger wire is better in cord sets.


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## Cole82 (Nov 22, 2008)

jrclen said:


> Voltage drop is dependent on the distance and the load. And can be fixed by using a larger size wire. Most 120 volt power tools would have no problem with around 110 to 128 volts. You could check with the manufacturer on your particular chop saw.
> 
> Just keep in mind if you check a receptacle or cord with a volt meter, the reading will vary with the load. So if you stick the voltmeter in the end of the cord with no load you might see 120 volts. Turn on the saw and cut a 2x4 and that voltage could drop by quite a bit.
> 
> Bottom line is, bigger wire is better in cord sets.


Thanks
But I am wondering if there is a way to tell if it's undersized wire coming out of the HO wall socket. I was useing a 25' cord that was big rated for a/c units. Sorry I don't know the gauge but is the bigest cord I have. The saw was spinning slower than normal, but thought it was because it was cold, now it doesn't turn at all after the smoke show.


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## K2 (Jul 8, 2005)

No your're not going to burn out any respectable saw because of 25 ft of cord. Ever. .. 

A little trick I learned when running my worm drives off of 3 or 4 hundred ft of 12 ga. If there is snow on the ground, bury as much of the cord in the snow as you can to get the extra kick.


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## jrclen (Jul 10, 2007)

Cole82 said:


> Thanks
> But I am wondering if there is a way to tell if it's undersized wire coming out of the HO wall socket. I was useing a 25' cord that was big rated for a/c units. Sorry I don't know the gauge but is the bigest cord I have. The saw was spinning slower than normal, but thought it was because it was cold, now it doesn't turn at all after the smoke show.


In real life I usually see no less than 117 volts under load at the last receptacle outlet on the circuit. Add in a 50 foot #12 cord and you will have no problems with low voltage. I wonder if your saw died of natural causes rather than low voltage. 

Us electrician people are required to adjust our wire sizes on longer runs to avoid excessive voltage drops. I guess it depends on who wired the place. Plug your cord into a receptacle near the panel if you can. When I install a new service, I always install a GFCI protected 20 amp receptacle outlet or 4, right at the panel for the other workmen.

There is no easy way for you to tell if the wiring is adequate except to measure the voltage.


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## Rockwood (Dec 1, 2008)

I ran my $700 HEPA vacume off of a household circuit for 2 hours and it smelled hot. I tried every circuit I could reach to see what was going on. When I plugged into the last one I had flames shoot out of the motor housing. Ouch!


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## Ten Fingers (Nov 5, 2006)

"now it doesn't turn at all after the smoke show"

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yup, You have to keep the smoke in. Things don't work after the smoke gets out.


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## mrmike (Dec 9, 2008)

New guy here & i'll put my 2 cents in- It is not low amps that kills the saws! It is high amps that makes them die! This is caused by prolong use on low voltage "caused by voltage drops" or a dull blade as another post mentioned.. The higher the voltage we have makes lower amps. Lower voltage=-higher amps thru the resistance of the wire. We can go back to the basic Ohm's law theory on this. E=IR. Most posts are right on the extension cords with heavier wire . 
On a 100' 16awg cord plus 50' of romex to the panel there would be an 11 volt drop at a typical 15 amp "skil saw'. A 14 awg of the same distance it would be 6.8 volt drop & a 12awg would be only a 4.3 volt drop. So the longer you go & the smaller the cord, the more voltage drop there will be & the higher amps will be ! Hope I made Sense


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## Electric_Light (Nov 25, 2007)

pudge565 said:


> The imax recommended voltage drop is 3%. So if the voltage is 120v you can go down by 120*0.03=3.6v so the lowest RECOMMENDED voltage drop is 3.6v.
> 
> If you hae 240v the max is 240*0.03=7.2v


That's not a realistic goal. The utility typically allows a deviation of nominal +/- 5%, so anything between 114-126v at the service panel is within expected service. 

Since contractors' tools are expected to be used with an extension cord, it's an engineering flaw if the saw is not designed to accommodate down to no higher than 110v or so. 

The solution I recommend is a 10% buck boost transformer at the outlet, before the extension cord. It isn't feather light, but I think it's more user friendly than a generator. 

http://en.wikipedia.org/wiki/Buck-boost_transformer

Every foot of wire drops a predicted amount of voltage per amp and the Volts per amp/foot depends on the wire size. So, to achieve the same level of acceptable voltage drop, the longer the wire, the fatter it needs to be.

Since home wiring is usually 14AWG from the outlet to the panel, there's nothin' you can do about it. If it's an indoor work, use a 20A circuit when you can since they're usually on 12AWG wire from panel to outlet. Not all 20A circuits have a 20A outlet with a side finger in the left side, unless it's only serving that outlet. 

The same hp motor needs 1/2 the amperage at 240v than 120v. The voltage drop in volts is 1/2 at half the amperage... 
1/2 the voltage at twice the voltage is 1/4 the percentage drop.

Let's say 120v motor, 15A. 
Extension cord drops 6v @ 15A
6/120 = 5%, so the motor sees a 5% drop.

The same motor if it can be used at 240v draws 7.5A
The same extension cord drops the same volt per amp but since the amperage is only half, you lose [email protected]
3/240= 1.25% drop.

Therefore, use 240v whenever you can.

Furthermore, induction motors(table saws and compressors) designed for 230v are MORE tolerant of voltage drop. The reason is that there are two common voltage levels in use and it's designed to accommodate both. 230v from residential and 3ph Delta derived single phase. Single phase derived from 208Y120v service, therefore many are designed to work with 208v or 230v.


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