Electrician Question

pajamasam

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So I made a mistake a screwed up my welder in the process.

I just wired my garage for 220. I put in a subpanel and ran 2 hots, 1 neutral, and 1 Ground from my main panel.

When I wired my welder plugs I ran two hots and I ran the neutral to where the ground was supposed to go(I know, Im an Idiot). That neutral was grounded anyways through the outlet to the box to the conduit to the subpanel.

Well I go to turn on my welder and it goes bang and wont turn on.

I fixed the wiring by taking out the neutral since I found out you only need two hots(and the ground terminal is grounded to the box) for 220.

But my question is why? what happened to cause the welder to kill itself. Aren't neutral and ground tied together back in the main box?
 

Bruce Jibboo

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not an electrician but I think [WRONG] neutral should go to neutral bar in sub panel [/WRONG] , then I think the ground actually would be routed all the way through the sub panel through conduit to the main panel neutral bar but I would have to look it up to be sure.

That's how the 110 30amp's are done.

I think we have couple legit electricians in here to clarify though? this will probably apply to the 220/30a I want to run to the garage for big powa shit.
 

pajamasam

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not an electrician but I think neutral should go to neutral bar in sub panel, then I think the ground actually would be routed all the way through the sub panel through conduit to the main panel neutral bar but I would have to look it up to be sure.

That's how the 110 30amp's are done.

I think we have couple legit electricians in here to clarify though?

So from my neutral bar in the house I have a large white wire that goes to the neutral bar in the subpanel.

For the Ground I have a large Green wire that goes from the ground bar in the Main panel to the Ground bar in the subpanel. EDIT: ( I used PVC to get from the House to the garage so I used a wire as the ground instead of the conduit)

They are two seperate bars in both panels but in the Main panel the neutral bar is grounded by a strap.
 

pajamasam

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ya we need legit electricians that are up to the latest codes to confirm, I wouldn't even trust googling, lots of dated info out there that may work but wont' be the safest for you or the gear.

Yea google had so much mixed information. Not only that people are using Ground and Neutral and common all interchangeable which i believe is wrong.
 

OffshoreDrilling

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your residential panel at home has two bus bars in it. the potential between the two bars is 220v, the potential from each bar to neutral is 120v

your neutral is a current carrying wire and your ground is a safety meant to dissipate current to ground. they essentially go back to the same
place but do not serve the same purpose.
 

Chester Copperpot

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Understanding 220 or 240 volt Electrical Circuits

Now for the quick explanation of 240 / 220 volt house current; Appliances which use straight 240 current (such as electric water heaters, or rotary phase converters) also have three wires:


1) A black wire which is often known as the "hot" wire, which carries the current in to the fixture.
2) Another "hot" wire which may be blue, red or white (if it is white the code actually requires it to painted or otherwise marked one of the other colors, but often it is not) which also carries current in to the fixture.
3) A bare copper wire called the ground, the sole function of which is to enhance user safety.

That's it, no neutral. Now, if you are paying attention, then you are probably wondering "If there isn't a neutral wire then how is the circuit completed?" The answer is that when one hot wire is negative, then the other is positive, so the two hot wires complete the circuit together because they are "out of phase". This is why 240 volt circuits connect to double pole breakers that are essentially two single pole breakers tied together. In the main panel, every other breaker is out of phase with the adjoining breakers. So, in essence 240 volt wiring is powered by 2 - 120 volt hot wires that are 180 degrees out of phase.
 

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your residential panel at home has two bus bars in it. the potential between the two bars is 220v, the potential from each bar to neutral is 120v

your neutral is a current carrying wire and your ground is a safety meant to dissipate current to ground. they essentially go back to the same
place but do not serve the same purpose.

This.

What happened to you is odd honestly. If I didn't know any better I'd think you had a hot and a neutral reversed or something.
 

pajamasam

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Here is a quick diagram to show what I did.
 

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OffshoreDrilling

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Thanks for the explanations guys. That makes sense. The second hot leg is negative while the first one is positive giving you 220.

But why did my welder die when I had a negative wire to the ground terminal of the plug?
nuetral is not negative.

in theory there should have been no problem with the wiring cooking the welder. I'm guessing you had a shared nuetral wire from another circuit that's using 120, and had that pushing through the welder, making it not happy. Each 120v circuit needs its own nuetral, or you can have current flowing in a wire even when a breaker is off. essentially backfeed from another circuit. major no-no. or total dumb coincidence that your welder kaput'

double check your voltage rating on the welder, actual voltage at the outlet, and if there is a voltage switch on the welder, that it is in the right position
 

pajamasam

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nuetral is not negative.

in theory there should have been no problem with the wiring cooking the welder. I'm guessing you had a shared nuetral wire from another circuit that's using 120, and had that pushing through the welder, making it not happy. Each 120v circuit needs its own nuetral, or you can have current flowing in a wire even when a breaker is off. essentially backfeed from another circuit. major no-no. or total dumb coincidence that your welder kaput'

double check your voltage rating on the welder, actual voltage at the outlet, and if there is a voltage switch on the welder, that it is in the right position

Sorry mistyped that. I edited it.


All the 110 stuff in the garage has its own neutral going to the neutral bar. Could It have backfeed through the neutral bar back into the welder?
 

OffshoreDrilling

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Sorry mistyped that. I edited it.


All the 110 stuff in the garage has its own neutral going to the neutral bar. Could It have backfeed through the neutral bar back into the welder?

no.

think of the wire like plumbing. if the drain (nuetral) backed up and was shared by your toilet and tub, you'd have to possibility of backing up crap into both before it got to the main sanitary line(nuetral bus)
 

OffshoreDrilling

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without being there and knowing what you changed around between initially wiring it, what you did to fix it, what voltage you were actually seeing there, etc, it's hard to diagnose what exactly happened to the welder.

right now you should be reading 220v between the two lines, 120v from each line to ground.
 

pajamasam

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without being there and knowing what you changed around between initially wiring it, what you did to fix it, what voltage you were actually seeing there, etc, it's hard to diagnose what exactly happened to the welder.

right now you should be reading 220v between the two lines, 120v from each line to ground.

Yea I get it.

I fixed all the 220 outlets by disconnecting the neutral wire from the ground terminal in the outlets and taking the neutral wire(for the 220 outlets) off the neutral bar.

Before I fixed it, i still was getting 120 from each hot terminal to the ground(and neutral at the time).
 

FESTER665

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three phase is a cakewalk. you can literally not wire it wrong. motor spins the wrong direction? change two leads, done.


We used to always mess with new people when I work as a maintenance worker in a slaughterhouse... "Well what leads did you swap?!?!" OMG you did it wrong !!!!

When I worked for the state emissions program we had huge 3 phase motors running the dynomometers in the ground, those things SUCKED to change out. The worst part was the controllers for them were SOOO picky.

I used to have all the leads memorized for high/low, etc. but haven't touched it in so long I couldn't tell you anymore. Luckily it's usually right on the faceplate.
 
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