Home>Discussions>ELECTRICAL & LIGHTING>Why do I see visible spark in power tool now..?
3 posts / 0 new
Last post
Why do I see visible spark in power tool now..?

I recently installed new GFCI outlet and in my understanding I did not do anything wrong and first time (after new outlet install) I turned the circuit breaker on in the main panel I saw a spark in outlet ....so I was kinda nervous ...something did not feel right but I went ahead and test GFCI receptacle and it turned yellow and I checked other outlet in the circuit which was after this new GFCI receptacle in the line....(New GFCI outlet I installed is the first one in that circuit) ..there was no current at other outlet so I was kinda relaxed. Than I reset the button and hooked my senco screw driver but I saw visible spark ...I tried couple of time but it was visible spark both the times...well next I checked another corded drill and same thing...visible spark......I have used these screw drivers/drill before and never saw any visible spark either in day or night...so what do u think I have done wrong in this new outlet installation that is causing visible spark?

Of course for now I have turned off that circuit in the main panel ...and not comfortable using this circuit unless I solve the problem.

A. Spruce
Re: Why do I see visible spark in power tool now..?
A. Spruce

Can't help you with your GFCI issues, but I can say that there is not one power tool out there that doesn't spark as the brushes rub across the segments of the armature. Some are worse than others, and this has to do with the quality of the tool and the age of the brushes/armature/tool.

Re: Why do I see visible spark in power tool now..?

Have you tried these tools in other non-gfci outlets?

Depending on what point in the incoming power cycle you switch a load on, you may or may not experience a spark in the switch.

Our 120V (RMS) power cycles from zero to +169.7V (peak) down to 0V (zero crossover point) then down to -169.7V then up to 0V, 60 times per second.

This means there are times when to may switch on a load and it will feel 169.7 volts and arc at the switch. Likewise you may switch on a load when the voltage is 0V where no arc occurs, you don't pit the switch or stress the motor or lamp.

Good circuit design only allows switching at the "zero crossover" point. But, almost no residential circuits have this feature.

However, many single pole residential light switches have "tungsten" rated contacts which can withstand the occasional 169.7V surge to an incandescent lamp.

Go to a dark room with a standard light bulb and switch it on and off 100 times. Record the number of times you see a spark in the switch. BTW, the bulb may fail if it feels too many 169.7V "hits".

Sorry for the long post.

Sponsored Stories

TV Listings

Find TV listings for This Old House and Ask This Old House in your area.