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ShortFuse 01-07-2013 03:16 PM

Voltage drop after an error
So ive had this custom potters wheel for a while and have been trying to get a way to have speed control. In my fumblings I hooked up a dimmer switch. The wheel is not the problem but after I plugged it in is. So I plugged it in and the lights went out. My studio is in a pole barn and it is scarcely wired. I know I had too much on a 20amp breaker but the thing is the breaker didnt flip off. I noticed the lights dim when I tried to get the motor to accelerate, it never did.

So I went to the breaker box and like I said it wasnt flipped. Im getting power but not enough. The lights will work but Ill plug in a fan to test and everything will dim. I removed one outlet from the one wire to reduce the load but nothing changed. I replaced the only outlet on that line and I have the same issue. I swapped breakers and still the issue is present.

Im lost and not sure what is wrong. Could I have fried the main breaker? Can the wire just give up? I didnt see any burns on the wire to the box. This breaker box is tied into the houses box and believe thats through a 60 amp breaker. That one didnt trip either.

What else could it be?

Btw Im new to the forum. Happy to be here :)

mpoulton 01-07-2013 03:30 PM

Try turning all of the relevant breakers off and back on. That's the branch circuit breaker, the main breaker in that panel, and any other upstream breakers (like a service disconnect) that you might have.

If it's still happening, then you'll need to take some voltage measurements to start diagnosing the problem.

rrolleston 01-07-2013 03:37 PM

Is there a breaker panel in your studio supplied by a 20 amp double pole breaker or is it a single just feeding one circuit in the shed?

joed 01-07-2013 03:39 PM

Sounds like a possible loose connection.

Oso954 01-07-2013 05:26 PM

You don't use a dimmer switch to control motor speed. Today, a dimmer and a motor control are two different things (unless you found an old fashioned rheostat)

If the dimmer is still in the circuit, get it out of there.

I wonder if you somehow crossed wires and put the lights and outlet in series ??

dmxtothemax 01-07-2013 05:41 PM

Sounds like you lost a hot,
And your getting backfeed,
this would explain the low power !

ShortFuse 01-08-2013 01:47 AM

Yeah I know I shouldnt of done the dimmer switch. I was dumb and jumped the gun without doing my usually Google Info Dig. Now Im reaping from this aggravating issue. I was rushing to get to work earlier so Ill be more thorough with my explanation now.

No I dont have the dimmer or anything plugged in. So the noticable effects were : When i first clicked the dimmer on the lights went low. I looked up and noticed that the lights fluctuated depending on the dimmers intensity, yet the lights never went to full brightness. I was confused because after I lost the lights completely and walked out to find the breaker didnt flip. I went in and fiddled with every switch then next to the window I heard the faint moan of one of my venting fans. I thought its very slight movement was from the wind. So I twisted in a light bulb that use rarely only to see it at the faintest of glows. So the main line comes in from the breaker, it being a single pole 20 amp, to one outlet. Then from that outlet it goes over to a light post (the one I mentioned I rarely use) and from there to another outlet where the line ends. The lights were originally attached to a power strip that had a cord that eventually plugged into another strip that was plugged into the outlet at the end.

I know the setup wasnt ideal but I have been slowly making my studio more efficient and up to date. So I unplugged the power strip from the end outlet and made the power strip the lights were plugged into be plugged into the first outlet. Basically I was trying to eliminate from the end of the line first. I gained a bit of power but it would still dim when I would turn on my oscillating fan that I was using as a test. I detached the end outlet and even cut out the light post leaving only the one first outlet which I did replace with a new one. Still had the issue.

I went to the breaker box and swapped out the single pole 20 amp breakers with some extra single pole 20amp breakers I had. The issue still persists. There are only 2 other lines going into my studio; My 60 amp kiln outlet that has nothing else tied to it and another 20 amp outlet that stands alone. I did plug the fan into it to test and it seemed to be dishing out the right amount. I should of used a meter to test all of this but i was just using the fan to create a load to see if the pull would dim the lights. I was stumped after I cut down (not literally) any load besides that one single outlet and the issue still persisted.

I havent totally checked but I was told the breaker in the house is a 60 amp that supplies the pole barns breaker box. This isnt the first issue weve had living in this house so Im not really sure what the person who wired it all was thinking.

AllanJ 01-08-2013 08:17 AM


Originally Posted by dmxtothemax (Post 1088497)
Sounds like you lost a hot,
And your getting backfeed,
this would explain the low power !

To test for this, flip off all breakers that serve 240 volt equipment such as a clothes dryer or stove. Now any light or appliance getting power via a backfeed through a 240 volt appliance will go dead.

Are lights in different places throughout the house affected? Incandescent lamps reveal voltage problems more noticeably compared with compact fluorescents.

Do not let a dim light or weak appliance operate for more than a few seconds with five minutes wait before the next try/test. If (very likely) you have a loose connection, which could be some distance away, the loose connection will heat up and could cause a fire.

ShortFuse 01-08-2013 12:38 PM

I see what your getting at but the house isnt affected at all. it is completely separate besides the one breaker for the pole barns breaker box.

I fiddled more with it today. I flipped the breakers and changed there positions back to where they were to begin with. I have a multimeter and I think I had it on the right setting ACV 700. No other setting really gave a reading. I looked up the setting and i was told to use the VAC 750, this harbor freight version didnt have that.

So the noticable symptoms today were odd. So from the box i have three breakers. On the left is a 60 amp for my kiln which is always off unless Im firing. The right has the two 20 amps which lead to my two outlets. To problem solve with the voltage pull Ive used two fans and two lights. The two lights are on a power strip and plugged into outlet A (also breaker A). One fan is in outlet B (breaker B) and when turned on it seems to have full power and the lights on outlet A actually get brighter. I proceed to plug the second fan into outlet A and when turned on the lights dim slightly and the fan on outlet B gets stronger.

When using the meter outlet A and B read 128 with out anything plugged in. When the lights were plugged into outlet A the second plug on outlet A read 88. Same for outlet Bs plugs. Once the fan on outlet B was turned on I recieved no reading or the occasional 1.

AllanJ 01-08-2013 04:05 PM


... get brighter ...
The loose connection is in the neutral line somewhere.

You should unplug all electronics (including microwave ovens) from and better yet not use anything at all on the affected circuits until this is fixed.

Lights getting abnormally bright means excessive voltage which is harmful to all electrical equipment.

ShortFuse 01-09-2013 02:51 PM

So I detached all the old wires. i did leave the kiln wire hooked up only because the breaker is off until I need to use it. I bought new wire, new outlet, and switched the breaker. The issue still persists. Spoke with a friend that is an electrician and he believes it to be a neutral issue. I used my better meter and tested the hot wires to the box and Im receiving the right amount of power to the box. The outlet read 121.5. I even put the breaker on the other side of the box, wires and all, and still the issue persists.

Although come to find out that the box in the pole barn only has 2 hot and Ground. Theres no neutral line. Its never been an issue before this so I cant see it being one now.

Out of curiousity I decided to see if I would get the same dimmed loss of voltage if I popped on my kiln. Figured if a fan would dim the lights the kiln would kill em. Yet when I popped on the kiln the lights glowed brighter. Some of my searches have led me to a possible bad bus bar, could it be? everything is clean and the breaker box is probably a year old, but could the main breaker be bad. Here is what Im looking at...not much.

AllanJ 01-09-2013 05:44 PM

You are currently unable to operate any 120 volt equipment on the studio system with just 2 hot wires (240 volts) and ground. You may not wire up 120 volt circuits by connecting the neutral wires to the subpanel ground terminal strip (ground bus bar).

Short of replacing the feed back to the house with a new 4 wire feed (hot, hot, neutral, ground) the only way to use 120 volt equipment in the studio is to get a 240 volt to 120 volt transformer. You will probably need to replace the feed cable anyway (if it is underground) since given your symptoms there is a good chance the ground wire (is it aluminum?) has rusted out due to biodegraded or animal chewed insulation at some point between the studio and the house.

Are you getting abnormal voltages back at the house when you turn on 120 volt things? The loose neutral could be back there.

(Neutral problems don't show up when you turn on a 240 volt appliance.)

jlmran 01-09-2013 10:54 PM

Based on the picture, it looks like the kiln circuit is 120/240, not 240. I see a white conductor.

But I don't know how this accounts for the gremlins. Just an observation.

ShortFuse 01-17-2013 03:41 AM

So my issue of course was the neutral problem. Had a electrician friend come out and test some things that i didnt think to test. So the next step was to rewire the box to our shops box to eliminate the connect to the house. We have two meters and its preferable to have the two "shops" linked. So the quote i received was a little outrageous for our electrician friend to do the job. We could of just replaced the ground with a neutral and sunk a ground rod, but the more expensive route was considered sadly.

Anyways so the city owes us some trees and in an effort to maybe exchange the debt we called them up. Their policies have changed and dont do jobs that arent off the main line, but because we live in such a small town with good ol country boys they spoke about how to DIY.

So they spoke about using no.4 triplex wire then sinking a ground. but connecting it too a 100amp box before connecting it to the shops box. So I dont get why the power would have to go from Box 1 (literally a foot) to 100amp box 2 then 150 feet to box three with no4 wire. 3 boxes for one line. So you have breakers for oulets, then a breaker for a box, and then another breaker for another box. Makes no sense to me. Right now the box is hooked up via no.3 if im not mistaken. Its definitely a smaller wire but defintely not as big as the no.4.

I dont see the need for another box and the use of the no.4 wire when the first box was hooked up with something lighter and the only reason it went south it the lack of a neutral. So could I run the no.3 triple cord, run the ground bar from the box in the studio, and then hook the two hots in the shops box with a 60 amp breaker? which would be duplicating the first set up but adding the help of a complete circuit.

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