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-   -   neutral wire became ground? (http://www.diychatroom.com/f18/neutral-wire-became-ground-60294/)

okedomantakeshi 12-25-2009 11:42 PM

neutral wire became ground?
 
I bought a house built in 1953. and tried to hook up electric dryer
using 240v 30amp 4-wire system. wire and breakers stuff were arleady
there but I had to buy a receptacle and 4-prong cord for my dryer.
I hooked it up each wire to same color wire and to the back of the dryer.
The dryer didn't start. I checked the voltage at the receptacle. Between
black and red was 240v. Between black and white, black and ground was
around 110v. Between Red and white, red and ground was 110v, too.
But I checked the back of the dryer connection place, between red and
black was 240v, and I don't know why but red and white was 240v, black and white was almost
0, and black and green ground was 120v.
when I connect green to white terminal of dryer and white to ground terminal of dryer. It started and worked normal.
Can somebody tell me why? and any recommendation about my
situation? Thank you

frenchelectrican 12-26-2009 12:21 AM

Did you double check the netural and ground connection ?

Here the diagram how it should be correct

http://www.cornerhardware.com/howto/images/ht052_1.jpg

next step is dryer terminal strip This is a correct verison for 4 wire set up

http://z.about.com/w/experts/Electri...wire-dryer.gif


If done right it will function correct.

Those two photo will show very clear how it hook up properly.

Merci,Marc

okedomantakeshi 12-26-2009 01:51 AM

Thank you frenchelectrician.
Yes, I checked them both (receptacle and dryer connection) more than
3 times.
my house is old and I have 2 electric breaker box (one is old type glass fuse and one is regular breaker) I think someone switched ground and neutral somewhere but is it possible?

frenchelectrican 12-26-2009 02:26 AM

It may can do that however at the main fuse/breaker box the ground and netural will be together but once you get subpanels the netural and ground must be seperated so .,

What you have to do is track that dryer wire back to the fuse or breaker box to verify the connection and between the main box to sub box and the subbox will have 4 conductor set up if you have 3 conductor set up it will rasie few issue with this.

You will have to double check the connection in both main and sub boxes to make sure all the connection are correct.

Merci. Marc

okedomantakeshi 12-26-2009 02:44 AM

Thank you, frenchelectrician.

I track down to sub breaker box and there is one metal bar next to
braker panel and ground wire( there are a couple of bare ground wire)
and white neutral (one that is to the dryer) are connected to the same bar but different holes. Main fuse box has 4 grass fuse but I didn't track
down to there.
But frenchelectrician, do you think I can continue using my dryer like as it is (ground wire to neutral terminal of dryer and neutral wire to ground terminal of dryer)?
could you give me an advice?

thank you

frenchelectrican 12-26-2009 02:53 AM

Ok with subpanel you should see the netural and ground on seperated bussbar the bare copper is on ground bussbar and netural should be on netural bussbar.

What brand name subpanel it is I can able tell where that located.

Any chance can you get photo attached to this fourm ?
that will really help alot in here.

Merci,Marc

okedomantakeshi 12-26-2009 03:12 AM

thank you
There is only one metal bar and neutral and ground are connected to the same bar but different hole. Is this a problem?
I'm sorry I don't have pictures right now but if possible i will do it tommorow. I think brand name is Murray.
Do you think I can use my dryer or does it make any problem?

thank you

frenchelectrican 12-26-2009 03:33 AM

I know you mention me about the netural and ground is switched around so look at the subpanel both ground and neutal is on the same bar that should be ok for now but really the whole electrical system need to be updated due you have old glass fusebox there I know most case they have 60 amp main fuse and it don't take much to blow the main fuse once you have dryer going and stove is on and few other items on the same time.

When that subpanel was installed I know the old codes they used allowed three conductor before but not anymore it was no longer legal it was changed few code cycle back.



I just got one done couple days ago { In France } they did have old fashion wire fuse that is worst than glass fuse. that place it only have two fuse for whole house { I am not kidding on that part :eek:}

Again I will suggest that not too far in future you will need to replace the main fuse box and correct the issue with subpanel.

If you have free time you can go ahead and send us the photo myself or other members in here will help you to get some idea how to deal with this situation here.

Merci,Marc

okedomantakeshi 12-26-2009 03:52 AM

Thank you, frenchelectrician.
I think you are very experienced and very good technician.
please be my master.

Stubbie 12-26-2009 09:16 AM

Quote:

I don't know why but red and white was 240v, black and white was almost
0, and black and green ground was 120v.
Since your voltage readings are correct at the receptacle but you are getting the wrong voltages at the dryer terminals your problem is likely in the 4 wire dryer cord.

Since the dryer works when you connect ground to the neutral terminal this tells me that your neutral is broken in the cord or at the clamp to the dryer wiring compartment or at the connection to the terminal block. You are getting 240 volts red to white and 0 volts black to white. Only way this can happen is if the white is broken in the cord and is shorted to the black wire. Your getting 0 volts on the black to white because both wires are at the same potential or in other words energized by the same hot leg. Your breaker is not tripping or fuse not blowing because the white is broken and you do not have the bond between the neutral and ground on a 4 wire dryer connection..so the fault cannot clear. Disconnect the dryer and remove the cord. Take a continuity test on the white wire, your going to find it does not have continuity and is broken or has been cut from too tight of a clamp or something.
http://media8.dropshots.com/photos/4...226/064010.jpg

Absolutely do not operate that dryer with the white connected to the ground screw !!!!

http://media8.dropshots.com/photos/4...226/063635.jpg

JohnJ0906 12-26-2009 09:19 AM

And make sure you remove the neutral-to-ground bond strap at the dryer.

Here are a few pictures I took - http://s125.photobucket.com/albums/p...t=0db53106.pbw

frenchelectrican 12-26-2009 04:09 PM

Stubbie.,

Thanks for the drawing that should clear up the details for OP and hope the OP get this before it get out of the hand.

John that is good photo to save that really save alot of time to describing it.

Okedomantakeshi.,

Please do follow those guys suggest first to veify the dryer cord is good or damaged if the dryer cord is damaged then it will have to be replace with new one but before you install it make sure you do not overtighten the strain relief clamp as you will see on John's photo if you get them overtighten again it will short out pretty easy.

Once you clear up that one then let us know how it come out on that one.

Merci,Marc

okedomantakeshi 12-27-2009 03:35 AM

thank you so much for good advice everybody.

I had checked continuity for dryer cord and everything was ok.
the ground plug had continuity to green cord, the neutral L-shaped plug
had a continuityto white cord and so on.
About the voltage at the connection of the back of the dryer, when I switched around ground and neutral, the voltage reading between red therminal of dryer and white terminal of dryer(I hooking up ground cord to it) went down from 240v to 120v.between black terminal and ground terminal(hooking up neutral cord) was 120v. and the dryer worked normally( i put my loundry in it and it dried perfect).
It is so weird but i'm telling you the truth.

I thoght since the white neutral wire and ground wire were connected to
the same iron bar next to breakers, neutral wire can be ground and ground wire can be neutral. I don't know who's going to decide neutral or ground
but I thoght it is possible. it's so weird. what's the difference between neutral and ground ?

frenchelectrican 12-27-2009 04:10 AM

I will put in simple layman term

The netural is grounded current carry conductor it will carry normal current. { the grounded mean it allready grounded on purpose like centre tapped transformer so that what we call Netural }The typical conductor colour is useally white or grey depending on what voltage it is { the grey useally show up with commercal location with 480Y277 system }{ however becarefull with switch loops that you will heed extra attetion due the white not always be netural ditto with 240 volts system which they use with XX-2 Romex cables }

The ground is grounding non current carry conductor it will normally NOT carry any current unless you have short circuit then it will trip the breaker or blow the fuse{s} The conductor colour will be either bare copper , Green conductor colour or Green with Yellow strip that is reserved for grounding conductor only nothing else for it.

Merci,Marc

retired7373 12-27-2009 10:27 PM

Quote:

Originally Posted by frenchelectrican (Post 372099)
I know you mention me about the netural and ground is switched around so look at the subpanel both ground and neutal is on the same bar that should be ok for now but really the whole electrical system need to be updated due you have old glass fusebox there I know most case they have 60 amp main fuse and it don't take much to blow the main fuse once you have dryer going and stove is on and few other items on the same time.

When that subpanel was installed I know the old codes they used allowed three conductor before but not anymore it was no longer legal it was changed few code cycle back.



I just got one done couple days ago { In France } they did have old fashion wire fuse that is worst than glass fuse. that place it only have two fuse for whole house { I am not kidding on that part :eek:}

Again I will suggest that not too far in future you will need to replace the main fuse box and correct the issue with subpanel.

If you have free time you can go ahead and send us the photo myself or other members in here will help you to get some idea how to deal with this situation here.

Merci,Marc


Sounds like a huge fire hazard, good luck, might want to think about having the house totally rewired
david


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