We actually have three sub panels or boxes with breakers. I looked at the small breaker box in our pool room. There is only one neutral bar. The three (one red, black and white) big main wires from the main panel go to the two hot bars and to the neutral bar. There is a green wire ground to a rod in the ground that is also connected to the neutral bar. So the sub panel is grounded right there by the connection from a ground rod to the neutral bar. So the neutral and ground ARE tied together at this panel. It is older wiring going back to the main panel, so only red, black and white, no seperate ground wire goes back to the main panel.

 

I also checked one of the sub panels in the barn. This one is newer and has red, black, white and ground wires running back to the main panel. This breaker box is also grounded to a rod with the ground tied into the neutral bar.

I don't think I understand why it is a problem that the sub panels are individually grounded??

 

Can anyone explain why this would be a problem?

 

Hey folks: I am still looking to understand why it is a problem if sub panels are grounded? Mjsparky363 mentioned this a few posts above. Really want to understand why they should not be grounded themselves. I checked all 3 sub panels and they all have a ground rod wired to the neutral bar.

Thanks.

 

Take the grounds off the nuetral bars in the subpanels. Put them on their own ground bars. What it is doing is creating stray voltage. You see this on farms alot. The ground rods are at different potential(they ground more or less depending on the material thay are grounded in). Basically, if one rod is grounded in sand, and one is in undisturbed black dirt, there will be a difference between grounding characteristics of the soil. If one circuit on the sand ground rod is on it will try to go to the dirt ground rod because it is easier to ground. Thus you have voltage going on your nuetral to the dirt ground. Recap, seperate the nuetrals and the grounds in the sub panels. Make sure you have a good connection between ground and nuetral in your main panel. This is where you ground the utility. Hopefully I didn't confuse you more, if so write back and I will try again.

 

If I remember correctly, under the new NEC codes, If main panel is more than 6' away from meter, an intermediate discconect must be used within 6' and the panel shall not be bonded(ground and neutral not tied together on same bar or have a jumper or screw installed to complete bonding of ground and neutral. In a sub panel, Ground and Neutral CAN NOT be tied together on the same bar. They must be seperate all the way to the main panel, with sub panel feed being a 4 wire feed.(black, Red, White, Green(bare). Now, If sub panel Is located more than 6' from main panel, than I'm not sure, as I have always used the 4 wire install for simpicity and safety. Do you have any **** and tube wiring in your house? (still common around here argg.....) seems your are getting phantom voltage from poor wiring installation and additions over the years. Why do you have sub panels? I should add, If one is located in a seperate building, then all you run is neutral, and 2 hot (phase 1,2) You then ground at panel with copper bar no less than 8' in the ground. Panel shall also be bonded. If most, are any of your wiring is older than the mid 70's, Replace ALL of it. New main panel, sub panels, ect. Now before you say I can't do that wait....
What you do is buy a book or two on residental wiring. then get a big piece of plywood some single, 3-way, 4-way switches and single gang boxes. a couple of recepticals and a light socket and some wire. build a mockup of circuts based on what you read in said books. Once you get the hang of it, and you will, Install a new meter base and main panel in you house. Have your local power company come certify and install meter and rewire one room at a time tying in to the new panel and remove from old panel. As homeowner you do not need to be certified electrician, just follow codes. Belive me, even though it sounds like a daunting task, residential electrical is very simple to understand. All you need is a little practice(plywood mockup) and a comprehensive book. You seem to have all the basics down on AC so that is what I would do if in your shoes. Good Luck, Dave

 

Thanks guys. I think I understand. Oldest wiring in the house is 1974. Much is Romex. Some is still the older pre-Romex tar like covered wire. I don't know the correct name for this. Someone changed all of the exposed wire in the attic and crawl space with Romex, but wire in the walls is still the 1974 stuff. With some study, I am capable of rewiring if needed, although some of the rooms like the kitchen and a couple of bedrooms with a second floor above would be tough. I have rewired several old house with all the walls removed, but only pulled the wires to the main panels. Then hired someone to do the panel and meter connections. Once I did the whole thing, but that was 15 years ago.

On the issue of sub panels. Closest one to the main panel is about 75 feet. The other two are in the barn about 250 feet away. Two are wired with red, black and neutral to the main panel. These two have their own grounding rod at the sub panels, connected to the neutral bar. If I understand correctly, these are fine like that.

The third sub panel is wired with red, black, neutral, AND ground to the main panel, 250 feet away. This one also has it's own ground rod at the sub panel. I will check this sub panel tomorrow and see if it has separate ground and neutral bars. If it does not, should I take the ground off the neutral bar? And then, what, if anything should I do with the ground rod and wire at the sub panel.

 

If it is wired that way that is ok. however I do belive that if you have that tar covered wire anywhere you probibally don't have ground at those circuts.

 

Even the third sub panel is ok wired as I described?

Where the Romex is tied into the tar covered wire, they attached the Romex ground wire to a clamp on a pipe. So each individual circuit that has any Romex has it's own ground. I have come across several of these in the attic and crawl space of the house. The bathrooms are wired this way and the GFI's seem to work ok. I really am beginning to think that rewiring the whole house has to be put on the schedule.

 

if the 3rd panel is 4 wire, seperate the ground and neutral at the sub panel and have a seperate neutral bar(not bonded to the panel) with just white wires landed on it. then have a ground bar bonded to panelwith only thebare or green wires on it. as for the other 2 subs(3 wire feed) if you still have the voltage to neutral, diconnect the neutrals at the main panel and bond the sub pnels to a ground rod and a water pipe.(or 2 ground rods 6' apart) this way you are treating it as a seperate service(just the 2 hots going to the subs and neutral is derived at the sub panel ground rods) THIS IS FOR TEST ONLY, if it clears up your neutral to hot voltage problem you need to add a seperate ground from main panel to subs.

 

If you decide to go the rewire route, my personal preference is square D. Either homeline or QO series. QO being more expensive, but I like the way the breakers install, and the fact that they show green for good and red for triped. Also, They have a better neutral and ground bar setup than say Cuttler Hammer. I always put my neutrals on one bar and grounds on another, even when bonded. Also, never put more than one wire on one stud.
Especially neutral.

 

Shepard, if you test a power outlet, with the power on to the outlet and nothing plugged in to it, what do you read?

 

119, 120, varies a little.