Help! Help! Eletrical box works -- sort of

[Anonymous]

This weekend, I sawed through romex wiring in the attic. The breaker tripped. No big deal, I put it together with a box and now I have an outlet up there. I plugged a radio in to the socket and it works fine. I tried my shop vac and it does not work. It turns on but the motor runs very slowly. (the shop vac is fine, other outlets it works great) I tried a drop lamp and it works great in the new outlet. I tried a circular saw, it get power but turns very slowly.

What is wrong? I thought I would have all or nothing, I never ran across a problem where there seems to be not enough amperage (if that is the right word) what else should I check? Is it unsafe?

[aphares]

Under a heaver load like the shopvac, or saw. this is causing a loose connection to be looser. Under a litter load like the lamp the connection is holding.
If you used a device that wires can be inserted into back holes, redo the outlet with installing the wires on the screws located on the side, clockwise around the screw.
If you used wire nuts and pigtails re check the nuts, be sure they are tight, and the wires inserted all at the same length. If the nut is making a popping noise the wires are not set properly.
Check the location at the outer sheath, and the insulation to be sure it was not damaged when it was stripped. Something you might of missed.
If the saw jumped when it hit the wire it could be possible it nicked it in a location you missed on examination.
Hope this helps
Post back let us know how things turned out.

[Anonymous]

Thank you for the reply. I did check the connections, in fact I replaced the outlet, in case it was bad or connections weren't good. I also checked the wiring and it looks fine but could it be damaged further into the romex line? do you think it could be an other oulet in the line that may have gotten damaged when the wire was cut. Also is it possible that the breaker was damaged?

[aphares]

Did the breaker do its job and trip? Unhook the wires on the breaker, then reset it and test the voltage, this will eliminate the breaker. Or if you have no voltage tester, fill for the breaker to be solid. Good indication it is ok, but not reliable. In the panel tighten the white wire on the side block just to be sure it is ok If you problem is at the new plug, then it is between the new plug and the breaker, if the new plug is ok, and the problem is at the next plug, the problem is between this plug and new plug, so on, but must start at first plug on the circuit,
Post back and let us know what you find.

[Wgoodrich]

Often times you may have had a loose connection in the existing circuit that was working loose yet not yet caused a problem. The short circuit when cut into with your saw may have caused that existing loose connection to have failed.

Open your panel up and look at the connections at the breaker and this white wire of that branch circuit on the neutral bar. Leave that breaker off and make a drawing as to what all is dead in the house that is not that branch circuit. Once you have mapped out that branch circuit do as aphares suggested and start at the first receptacle or light on that circuit and work down to the end of that branch circuit checking each recepacle, switch, light and wire nut looking for a loose connection of damage due to heating of a conductor at one of those connections.

I agree with aphares your problem is a loose connection he also gave sound advice to start at the beginning of the circuit. I added that start of that circuit would be at the panel on that breaker and neutral bar.

Really doubt the breaker has a problem I believe it is just doing its job, a loose connection is your problem source.

Good Luck

Wg

[Anonymous]

Could it be possible that the wire that I cut into was from a switch
to a ceiling light. By reconnecting the wire and adding an outlet
to this line - would it light a trouble light but not run a shop-vac ?

[Wgoodrich]

It is possible and a good shot of you being right that this may be a switch leg. Remove the receptacle and just wire nutt the old circuit wires black to black and white to white without connecting in the new receptacle then see if all works fine.

If the circuit works right after you wire black to black and white to white without the receptacle being on the circuit then take a voltage tester while the switch is in the on position and test between the black and bare you should find 120 volts. Then test from the whte to bare and if you have 120 volts then you have cut a swtich leg.

Let us know what you find

Wg

[Anonymous]

Ok, I got rid of the outlet box and just installed a box and wire nutted the ends. Everything works fine now but...

When I had the outlet in and lighted a drop lamp a light downstrairs (which I thought was the switch leg) would come on very dimly. When I turned on the light swith connected to the dimly lit light (downstairs) now the drop lamp would turn off and the downstairs light would turn on. It was almost like I was closing a circuit by putting the drop lamp in the outlet. I don't get it because if it were the switch leg I should get nothing upstair with the light switch off but I didn't, I got enough power to run the light but not enough to run a shop vac and, to add to the confusion, the light downstairs (with the switch off) would glow dimly with the switch off when the drop lamp was on in the attic. This house was built in 1976 so there is modern wiring there (14-2 romex).

Thank you all for your help. I am glad that everything is working good now. I just don't understand what happened. :roll:


Thanks!

[Anonymous]

holmes,
Heres what happened: You installed a receptacle in a switch leg from a fixture that has a hot and a neutral at the fixture but only the hot goes to the switch and back. The receptacle made a complete circuit back to the switch so the fixture worked fine. Then you plugged in your drop light and created sort of a short circuit thru the filament in your drop light bulb which acted like a switch with a lot of resistance (because of the filament) and sent enough voltage to the fixture to light it dimly. Then when you turned on the switch to the fixture the voltage now has another path with a lot less resistance so the fixture lights brightly. Remember, the fixture could light with the switch off because the power originates at the fixture, not at the switch, you just created sort of a switch ahead of the original one.
hope this helps

[Wgoodrich]

joefixit pretty well said what you wanted to know but thought a term added would help explain.

YOu created a series wiring circuit making the light bulb as joefixit said to be a part of the circuit.

Series circuits deliver power to your second light futher down the circuit only through the resistance of that light bulb which is not very conductive. This greatly reduced you ability to use any loads downstream on the same wires because those downstream loads had to run through the light bulb.

The shop light worked becuase it did not pull much current and was able to light up passing current only through one hot wire same as christmas light bulb strings are wired. In christmas lighting string if one bulb fails the hole lighting string fails.

Series wiring designs passing the flow of electricity through one load to get to the next load is only possible in low amp load eqiupment like a light bulb. The motor pulled too much current to be able to operate in a series wiring method.

Try looking at the following link on home wiring web site that may help you understand series versus parallel wiring designs. Look at the first two drawings showing the difference between a series and parallel wiring design. This may help.

http://www.homewiringandmore.com/homewiringusa/2002/definitions/parallelseries/parallelseries.html

Good Luck

Wg

[Anonymous]

Thanks for you help. I understand that the switch only breaks the black wire. The way I see it the power comes from the switch over to the lamp, I cut through that part and installed the box. Wouldn't the switch still control the box and the lamp? is power coming from somewhere else?

/Switch/__________[box]___________[lamp]
:arrow: :arrow: :arrow: :arrow:

So if the switch is in the off postition, the box and the lamp don't have power...right? but that wasn't what happened the box lighted a drop light and made the lamp glow dimly. I guess that there is more going on than I think.

I appreciate all of your help here and if you are so inclined, help me get this through my head! Thanks for all of your help so far!

[Wgoodrich]

In you drawing your power is not shown where it enters this system. We are convinced the power enters the light then only a switch leg goes from the light to the switch and back to the light carrying only the hot wire detoured to the switch and back without a neutal being in that switch leg going to hte switch. The neutral is directly connected from the power that enters the light box to the light fixture and does not go to the switch box at all. You must have a hot and a neutral. In your case if this was a switch leg only then your black and white wire both were hot wires with hot power going to the switch box on the white wire and the controlled [switched] hot wire going back to the light fixture on that black wire. No neutral is in that cable.

The reason you trouble light worked is by using the prinsiple of series wiring. series wiring are used in some components of low amperage loads such as light bulbs. Series wiring styles are not effecient enough to carry much load such as a motor.

Series load is creating a flow of electrons from hot to hot with your load between that hot to hot. This means that say one electron passes from the power in the light box down that white wire to the switch then through that switch and back to that light to make the light work [ceiling light] then through that light to the grounded leg [aka neutral].

Now you plugged in that trouble light in that path for the power coming from the cieling light box going to the switch. You tapped into that switch wire. When you cut a hot wire that is carrying current then you just stopped that current from flowing, but if you install a light such as your trouble light then the current is now completed yet forced through a second resistance [trouble light] to get to the ceiling light then through the ceiling light to the grounded leg [aka neutral completing the circuit.

The key to this action is you broke the hot wire path to the existing light and forced that current to flow through your trouble light so the ceiling light can make the completed path to the grounded leg completing the circuit. The flow of electricity through the hot wire routed through your trouble light forced the trouble light to work somewhat but not actually correctly due to the fact you installed that trouble light in series with a working loaded circuit.

The flow of electricity through your trouble light was just a baby riding on the back of the ceiling light trying to do its work. The electron had to pass through your trouble light hot to hot to get power to the ceiling light then to ground after that ceiling light.

Kind of like you touching a door knob that is going to shock you while I hold your other hand. You get a small charge and I get the big charge of the shock. You were in series btween the door knob [power source] and myself which was the completed path to ground. You get about 25% of the charge stealing that 25% from me. I only get 75% of the charge because it came in series through you from the door knob through you to me then to ground. Series wiring reduces work ability and makes each light bulb rely on the other light bulbs to work for it to work.

Hope this helps

Wg

[Anonymous]

Thank you, thank you - the light finally went on (in my head). I
now understand. I now see what you have been telling me all along - I just didn't connect.

Thanks for all you patience.

[Wgoodrich]

Glad to be of some help to you.

Good Luck

Wg