Temporary Ground for Computer Surge Suppressor


  #1  
Old 04-07-04, 03:10 PM
chende02
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Temporary Ground for Computer Surge Suppressor

My wife and I have bought a one-story house in Houston, TX that was built in 1959. It has cloth two-wire throughout, with no ground anywhere. I'm a software developer with 4 computers and more on the way and obviously need ground wire. I have numerous surge suppressors and it's my understanding I need a "real ground" for them to work properly.

Tonight I'm driving a temporary 8 foot ground rod near the office window (next to a fence post) and I have assembled a receptacle box (outdoor waterproof type) with a ground wire and a two-prong extension cord. This is going to be loose in my office until I've done proper rewiring. In the receptacle box I've put a GFCI on one side and a conventional receptacle on the other (it's a double-ganged box I believe it's called - it holds two receptacles). I'll bring the green ground wire in from the rod and the hot and neutral from the two-prong outlet via the extension cord. I've wired it correctly in the receptacles (second outlet is on load side of GFCI). I've tested the GFCI and it's wired correctly (I understand the new ones won't reset without power and without power connected correctly). The second outlet cuts out when the GFCI is tripped.

I just need to drive the ground rod and plug it in. Have I made any serious mistake here?

I need this to last me until I do the bigger job of rewiring the house. I realize this is by no means a permanent set-up, but any gross errors you can see I've made for a two-to-four-week duration?

Thanks.
 
  #2  
Old 04-07-04, 03:49 PM
J
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Yes, you have made a serious mistake. Because of the misleading use of the word "ground" in our electrical vocabulary, you have concluded that you needed a connection to the earth. But what you really need is a connection to the power company's neutral. The earth is a relatively poor conductor of the large amounts of electricity that are present in a fault situation.

The best bet for people in old houses is to run a new grounded circuit with a few new receptacles for your computer equipment.
 
  #3  
Old 04-07-04, 03:56 PM
chende02
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OK. Thanks for the response.

My key point (perhaps I wasn't clear) is that I need my equipment working ASAP. With no ground wire anywhere in the house or any ground rods for the panel (as per house inspector) I have no ground for the surge suppressors. Don't surge suppressors need a real ground? Like, to the earth? I understand that back at a new panel the neutral and ground wire are bonded but does that do me any good for surge suppressors? Don't they still need a connection to the earth for surges?

What is a fast way to get a ground for the suppressors? Adding receptacles and running new wire (wire that probably would require a new panel) isn't an option for a couple weeks at best.

What is my alternative?
 
  #4  
Old 04-07-04, 04:02 PM
J
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You are confusing equipment grounding with service grounding. Unfortunately, we used the same word ("grounding") for two different things. What you need does not depend on any grounding rods anywhere. Although you do need ground rods for lightning protection (and a couple other things), it is not necessary for what you are trying to accomplish. No, surge suppressors do not need a real connection to the earth.

Your temporary solution is to take the risk of damage to your equipment. Unless your power supply is very poor, it's not a large risk.
 
  #5  
Old 04-07-04, 04:05 PM
hotarc
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They do make surge supressors that do not not require a grounding connection. The surge is directed to built-in capacitors and then slowly released to the neutral line. I hear they are pretty expensive though.
 
  #6  
Old 04-07-04, 04:11 PM
chende02
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Again, thanks for the responses. I guess I'm confused.

If there's a surge, a standard suppressor dumps it to the ground wire. Right? But back at the panel this is the neutral wire (on a newer house). In my house, the "ground wire" doesn't connect to anything, so there's no place for the surge to go. What's the point of the surge suppressor using the ground wire then? It's the same as the neutral wire, and equally energized as the neutral wire in a surge, isn't it? I thought the only difference was the ground rod.

I've read hooking the ground wire on a three-prong plug to the neutral is a big no-no and also heard a lot of people still do it. This (I'm assuming) is not a short-term fix for this one circuit?

I'm trying to learn but I'm also trying to get my equipment set up. If I just plug my computers into the existing outlets should I leave out the suppressors if I don't have a ground?
 
  #7  
Old 04-07-04, 04:31 PM
R
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As you have already been told, what you did is dangerous. Please disconnect it.

There are two ways that you can add a ground to a non-grounded outlet. One way is to properly rewire the outlet. The other method is to add a green wire of the same gauge as the circuit wire (usually 12 or 14) that runs all the way back to the panel and connects to the ground bar.

You have added a dimension to the problem, but it doesn't change the two solutions.

You state that there is no ground connection for the panel. What you are stating is that the neutral from the power company is not connected to the earth via a ground conductor. Are you certain? I have known home inspectors to make mistakes. The connection may be hidden and hard to see. Double check what the home inspector wrote down. He may have been referring to the water pipes not being connected to the panel, or something similar.

Certainly if you have no ground that needs to be corrected, and should be addressed when you replace the panel and the wiring. The sooner the better.

However, that does not change your current situation.

My suggestion is to run your green ground wire to the panel in whatever way is convenient. Run it along the floor, down the steps to the basement, or whatever. Then connect it to the ground/neutral bus in the panel. The idea is to provide a route for any current to get back to the power company without traversing the neutral wire that connects to any appliances in your house.

If you don't want to do that, then run the computers without a ground.

Let me also attempt to address your other questions.

Power comes to you from the power company. They supply two legs of 120 volts and a return wire. The return wire is used to carry current back to the utility company. The power coming to you does not require a ground connection at all. It works just fine with no ground.

At the main panel in the house (usually), we connect the neutral wire to the ground. This is done in a variety of ways. The two common ways are to connect to the copper water pipe entering the house, and to drive a copper rod into the ground. This grounding is done to provide a reference point for the voltage in the house and to provide a secondary path for current in the event that a problem exists. For example, if for some reason your water pipes become charged with 120 volts, it should trip the breaker becuase of the nice path back to the power company which should draw a large current and trip the circuit breaker.

Connecting the ground prong to the neutral at a receptacle outlet is bad because the neutral wires carries current. If you plug in a grounded appliance, say a washer, the metal shell of the washer will become a possible source of electrocution to anyone touching it.
 

Last edited by racraft; 04-07-04 at 04:49 PM.
  #8  
Old 04-07-04, 04:51 PM
chende02
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This is information I can use.

I will check when I get home if there is a ground bar in the panel. The inspection said specifically there was no ground rod at the panel or any ground wire in the house. I assumed from that there was no ground bar in the panel. I will check.

As to disconnecting immediately you can consider that done because I never hooked it up. I was waiting to drive the ground rod until after I had run the idea past you folks here. I appreciate the feedback very much.

I have 50' of green ground wire I was going to put on the rod. If I can find a ground bar on the panel I will attach it to that instead. Just to be sure I understand, this ground bar is NOT the neutral bar?

If I can't safely attach the ground wire to the panel's ground bar, I will wait until I rewire to do anything at all. In that case I will use a GFCI and no surge suppressors for the short term.

The explanation of "not energizing the neutral through the house" by sending the current back to the power company through the ground was very helpful. I think I get it now. The ground rod is just for lightning then?

Thanks again to everyone for the input.
 
  #9  
Old 04-07-04, 04:59 PM
R
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At the main panel in a residence the ground bar and the neutral bar the same thing. There may be one bar or two bars, or even more. Ground wires and neutral wires can be connected to any bar.

In my panel I have two ground/neutral bars. They are connected together with a piece of wire, and they connect to the metal box. They also connect to the power company neutral and to my two means of grounding, a copper ground rod and my incoming water pipes.

It is only at sub panels that the grounds and neutrals must be separated. This is because having them connected would provide a parallel path for the return current, something that should not be done.

If it is unclear to you where to hook up the green ground wire, describe what you have and we can try to help.
 
  #10  
Old 04-07-04, 08:40 PM
chende02
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It occured to me on the drive home that the neutral and ground at the main panel was the same thing. I recalled reading that earlier so I'm clear on that now.

When I got home I opened up the cover to the panel and killed the main breaker. Behind the panel cover I found mostly white neutrals going to the neutral bar. I also found two newer circuits that had both the white neutral AND the bare ground both on the neutral bar (the A/C and a new outside light).

That answered my question about whether the neutral and ground were the same bar in my panel and I went ahead and attached the green ground wire from my temporary receptacle box to that (it took two seconds). I was a little miffed to find that both the phone's ground and the cable TV's ground were just fastened to the metal conduit above my meter with hose clamps. They were OUTSIDE the paint on the conduit so I highly doubt they're really grounded. I also found that the neutral wire going from the post above the panel and meter back to the pole at the back property line was just a bare wire. The two hot wires are wrapped around it and it's used to fasten the whole lot to my fascia. I'm guessing in 1959 this was normal but it sure don't look right compared to newer houses I've seen. I also searched extensively for a true (earth) ground but there is none. No other wires than the neutral and two hots lead out of the panel. Is this normal from that far back ('59)?

So, at some near future date the bigger rewiring job will begin and I'll probably be here asking 1001 stupid questions to be sure I have everything right. Until then at least I'm online.

Frankly the existing wiring and panel frighten me and I can't wait to get them fixed. The very idea of cloth wiring will keep me awake at night. When I helped my father build houses we used new wire and I sure want that in my house now, let me tell you. The panel's so rusted you can barely open it.

Anyone know a good electrician in Houston that would work with a DIY homeowner? Any tips on where to begin with this mess?
 
  #11  
Old 04-09-04, 08:12 AM
W
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First of all, the wire coming from HL&P (or Centerpoint or what ever they call themselves these days) that attaches to your house is called triplex and consists of two insulated aluminum conductors wrapped around a bare aluminum nuetral. This is standard and not necessarily old. Most overhead service entrances are this way. That bare wire is bonded at the pole to ground and in your meter panel to ground (or should be). It is at your panel that the nuetral (grounded conductor) and ground (grounding conductor) are separated.

As to surge protection. Think of an arrester as a high pressure relief valve. Most are MOV's (metal oxide varistors) that are essentially an insulator at normal voltage and a low impedance short circuit at high voltage. The idea is that when a surge occurs, the arrestor shorts the wires together to collapse the voltage across it. Since your computer is in parallel to the arrester, the voltage is collapsed across it as well and no damage is done. When the surge is dissapated, the voltage returns to normal and the arrestor becomes an insulater again (assuming the surge was not high enough to damage it). If the arrester is designed to collapse the voltage from hot to nuetral, then the lack of ground is not necessarily keeping it from working.

However, it is my understanding that most computers are designed to use the ground as a "sewage" system for corrupted data and other things and may not function as well without it.

Please note that I am not addressing safety here, just the arrester and service.
 
  #12  
Old 04-09-04, 09:39 AM
chende02
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Thanks WFO for the info.

Are you from the Houston area?

If you are, do you know of any reason in particular I couldn't get new service lines and have them buried? The overhead wires are very ugly.

Trouble is... I can't even find a website in Houston to find out who to call to ask questions about service. I want to know if I can bury the wires but I would also like to put in a new meter and new panel around the corner on my house to hide the equipment while rewiring.

If you know a good Houston provider site, let me know please. Thanks.
 
  #13  
Old 04-09-04, 02:42 PM
W
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I'm in Bellville, about an hour west of Houston.
I can't really speak for HL&P/Centerpoint. At San Bernard Electric Co-op, our Staking Engineers meet with the customer to agree on a mutually acceptable service entrance (ie-overhead vs underground, which trees to cut/ which trees stay, etc.).
If a service is already in place and the customer wants it changed, then the same procedure is followed with the customer picking up the tab. Underground is a lot more expensive and your yard may be such now that getting digging equipment in there is prohibitive.
Typically, the Utility owns up to the meter, you own from there on. If the meter is on the pole, the underground installation would be between you and your electrician (I don't know any electricians in Houston).
I'm sure HL&P/Centerpoint has a Customer Service department that can get you info on what would be involved. Finding that dept. is another matter.....I've never had much phone luck with them.
Good Luck!
 
 

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