old house, no neutral bar

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Sep 21, 2003
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So I've lived in this house for 8 years. One part of the house has wiring and a sub panel from the 50's. I had an electrical guy put in a new 200amp main service a year or so after we bought the home. Because of a recent problem at work I checked the old subpanel and both the Neutral and the ground wire from the main panel go directly to three connected bars. There was continuity between all three bars. I was told by the electrical contractor at work that this was not a good idea and that I could be causing damage to anyelectrical device on that sub panel. You want the Neutral and the ground to be connected in the main panel (which it is) and not in the sub panels. Come to think of it we have had a lot of problems.

Some of the old Fiber covered wiring does not have a bare ground wire so the black leg goes to the hot breaker and the white wire goes to this common ground/Neutral bar. Even the newer wiring had both the neutral wire and the ground wire going to the same bar.

So I went down to Depot and bought a bar to use as a neutral bar, but I ended up being able to isolate one of the three bars so that there was no continuety between the two ground bars and the third bar I would use for my neutral. I pulled the Neutral feed from the main panel and attached it to this isolated bar. I then pulled all the white wires from circuits that had a hot/ground/Neutral and attached them to the new bar. I left all the really old white wires that come off the Black/white no Neutral circuits on the ground bar. Have I done what needs to be done? When I now check continuity between the two ground bars and the new isolated neutral bar, I get pulsating continuety... on...off...on...off. Is that correct? I love and hate electricity.
 

Pin_Head

 
 
 
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I don't know what 3 "bars" you are talking about. Maybe your local code is different, but around these parts the neutral and ground busses are bonded in the main panel. Electrically, they are equivalent unless something fails. Older wiring lacked the ground wire.

I don't understand what you mean pulsating continuity. Between where? How are you measuring it? what is the frequency of the pulsation?
 
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Thanks for the response Pin.
This old box has a three bars that are all connected together, tiered. The first picture is of the bars before I made changes. The second is after I isolated the top bar with plastic washers and attachment screws. I attached all the know neutrals to this bar and left all the original wiring white wires (aren't these grounds?) attached to the ground bars. This panel is a sub panel, so I was under the understanding that the ground and nutral bars needed to be seperate. I was checking the continuity between the new non-connected ground and neutral bars. With no wires hooked up to the neutral bar there was no continuity between the two. When I hooked up the neutral wire to the neutral bar, then there was continuity between them, but the fluke meter was beeping on and off instead of the normal long buzz. i just checked again and it now has solid continuity between the ground and neutral bars. I may have had a bad connection on the Fluke. The question I would have is do I need to do anything with the original wiring white wires? Are they grounds or neutrals if there is no bare copper wire for the ground?
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Pin_Head

 
 
 
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I don't know about your local code for subpanels, but it is common practice for neutral wires (white) and ground wires (bare copper) to be bonded to the same buss in the main panel. You certainly don't want to have any floating neutral wires or grounds, so they should all be connected together wherever your code says to.
 
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Neutral and ground are connected in alot of boxes.If your individual outlets are 2 way you cant change them to 3 prong without running a seperate ground wire this is frequently tied to the neutral. But check your local codes! Mike
 
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Just a layman's opinion so take it for what it is worth, not much, especially considering you are working with a hodge podge home.

In modern wiring black red & brass are hot, white & chrome are neutral, bare copper & green are ground, whites can sometimes replace red in 240 applications, the ends are suppose to be taped with black or red tape when you do this.



Between the two hots you get 240v
From either hot to common you get 120v
From either hot to ground you get 120v but ground should never carry any current, its capacity should be fully available for bonding and safety.
from neutral to ground should be 0v

although ground and neutral are wired to the same place in the main panel as soon as you leave the main panel they are different and should never be the same again including in any sub panel,

reason being if ground and neutral are tied near the load and there is any resistance in the neutral you could have potential voltage bleed over into the ground system, if the neutral were to open you would have shock potential on all grounded surfaces like the casing of appliances


In older wiring it was white and black only, I think the ground was introduced after your sub panel was installed and certainly after the original date of the home if it has cloth wiring.



so it is good that you separated the neutral and ground in this sub panel, but why did you leave some of the whites on the ground bar?
 
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Thanks Raven,
I left the whites from the original white/black wiring attached to the ground bars as I thought maybe in the old wiring the white was meant as a ground not a neutral. I had read somewhere that the old wiring had the ground bar attached to a water pipe and then to earth. Do you think i need to move all the original white wire to neutral and just leave the newer ground wire on the ground bars? Thanks again.
 
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The old wires are just one black one white?
and these are 120 lines correct?
Then yes I think they should be moved from the ground to the common,

originally yes these neutrals would have been connected to both the center tap of the transformer and a ground like water pipe or a ground rod, when the idea of a separate ground started they became a current carrying center tap not a ground, in the main panel these are the same but these are in a sub panel they should be on the neutral and connected to the neutral in the main panel.

be aware my electrical expericne is not in household and I am not there looking at it, my advice is worth exactly what you paid for it.
 
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