Replies

1. 
   edlee516 | Dec 17, 2002 03:37pm | #1

   Why don't you ground the service now, leave enough slack in the wire so that when the service is done over you can still use it.  Then run some romex or whatever to the computer location.

   One rod likely won't do it (it's hard to get < 25 ohms with one rod), so put in 2 @ 8' apart hooked together with one continuous wire up to the 60a main panel.

   Ed

1. 
   raynb3 | Dec 18, 2002 10:57am | #3

   Thanks Ed.  The catch with grounding my service is that it is the original service, i.e. no breakers, no ground, only three 20 amp fuses.  Can I ground select outlets to galvy water pipe in the basement?  The posssible catch there being that previous owners replaced some of the galvy service with PVC (the total ground is 12" of copper interrupted by a dialectric union).  All advice much appreciated.

2. 
   4Lorn1 | Dec 18, 2002 10:33am | #2

   With wiring that old the best bet is to rewire. It is possible to thread just a new ground to a box but this violates the code and many inspectors, for very good reasons, discourage this practice. Once you get the wire into the box it is relatively easy to go ahead and pull in new NM cable, modern wiring, and do the job right.

   The existing K&T is abandoned in place or, what I prefer, removed to the extent practical. That prevents the confusion of finding the abandoned wire and not knowing if it is still active, needing to be preserved, or abandoned where I can chop it out of the way with impunity.

1. 
   BillHartmann | Dec 18, 2002 08:15pm | #4

   ". It is possible to thread just a new ground to a box but this violates the code and many inspectors, for very good reasons, discourage this practice."

   No, the code specifically allows this. I guess the reasoning is that a separte ground wire is better than none.

   250-130 (c) in the 1999 version.

   Someplace I had seen a more detailed discussion of this with reference to current code sections, but I could not find it, but here is one reference from the 96.

1. 
   fireball | Dec 19, 2002 02:38am | #5

   RAYNB3*,

    You really don't want to just take a wire from a water pipe up to the receptacle you want to ground.If you had a small fault on the circuit,not great enough to blow the fuse,that current could flow through your plumbing pipes for a long time undetected.Is that serious?Homeowners have been fatally injured working on their plumbing with exactly this situation,and that's why it's not allowed by code.

    I'm sure you realize that you need a service upgrade,and that's a bigger need than covering your butt on the surge protector warranty.If you're really in dire straights start with running a new romex homerun from your computer receptacle back to the panel.

1. 
   raynb3 | Dec 19, 2002 11:25am | #6

   Thanks Barry,

   I think my biggest problem is that my service is circa 1930's 60amp two wire K&T with three 20 amp fuses - no ground and no breakers.  Eventually I'd like to replace the service with a modern panel and even rewire the house.  Until then, can you guys give me some hints on simply adding a grounding mechanism (ground rod?)to which I can make NM cable runs, while leaving enough slack for the future service panel?

   Not grounding to water pipes now makes perfect and life protecting sense.

2. 
   4Lorn1 | Dec 20, 2002 08:25am | #8

   Hmm. OK. I was wrong. Adding just the ground conductor is, was as of the late 90s, legal by the code. It wasn't a few code cycles back it would have been a violation of 300.5(I). Dealing with all conductors of the same circuit, including the neutral and ground, having to be in the same raceway. This had for years been the easiest reason to cite in the NEC against a separate ground wire being threaded in to ground ungrounded circuits and was often used by inspectors.

   Changes in 300.5(I), 300.20(A) Exc #1, 250.130(C) now, as of the mid 90s code cycles, makes this method allowable by the NEC. That is not to say that this is a great idea. My objection and the objection that remain from the AHJ in this area are that the efforts and techniques used to install a single wire are, with but a very few exceptions, are same as those used to get a new cable installed. Given the likely age of these ungrounded circuits replacing all conductors with a new cable is, IMHO, a good idea.

   The other point an inspector pointed out is that these single conductors are much more subject to damage. Once damaged a ground wire would show no symptoms of being disconnected until it fails to prevent a dangerous shock. A ground you can't count on is not necessarily better than not having one and knowing it.

   In the short term a new piece of Romex run back to the main panel would serve for a computer circuit. You are right the surge arrestors will not function without a strong ground. In this case connecting the ground to the neutral bar at the first point of disconnect, the first panel connected to the meter, would be fine. If no ground rod, a set in many areas is necessary, is present at the meter I would hammer in two and connect this also into the neutral bar.

   As stated in your initial post you need a new service, panel and, from the sound of it, a complete rewire. Ask around for a contractor that does a lot of old work, remodels and rewiring, as they will be more familiar with the techniques that a contractor that primarily does new construction. It won't be cheap to have the job done right but if you don't cut corners you will have an electrical system that will serve your family safely and well for generations.

1. 
   fireball | Dec 21, 2002 04:31am | #9

   Ray,

   Tips for driving ground rods :

   1.An easy way: Have the backhoe on site drive them with the bucket.

   2.Next easiest: (besides having the neighbor kid pound away while you smile),get the big Hilty drill out,or rent one, put the ground rod driving attachment on it,and watch it disappear.

   3.OK ,you want to do it the hard way.Get a helper to hold it with a pair of channelocks while you stand on the ladder and start pounding with a sledgehammer.Remember those charts with descriptions of loose sandy,rich loam,and hard packed clay soils ? You'll find out which one is next to your house.

   Don'ts:

   Don't put it right under the meter,you'll hit the meter with the sledge,it's happened.

   Don't line it up right over where the water ,gas,or sewer enter the house.There are bummer stories about making this mistake.

   Don't angle it in towards the house,eventually you'll hit the footer and be  disappointed.

   Don't stop with it 3 inches above grade.On a five acre lawn your two year old will find it and fall on it surer than sh+t.I dig a one spade depth hole first,and then stop when the rod is just below grade.Make your connection to the grounding electrode conductor and route the wire to come out of the ground right next to the house.If need be the inspector can look at it before you fill the hole in.Leave it above grade and you get to fix your lawnmower.

   Try to do it after it's rained.Around here dry hard clay can be like rock to drive a ground rod through.Pick a helper who likes to play "Who is more macho?".We used to play that if you couldn't drive the rod 18" without stopping you had to squat to pee the rest of the day.

   Have fun.

   Barry

1. 
   raynb3 | Dec 21, 2002 10:58pm | #10

   Thanks for all the great ideas and info.  I will consider all contributions, future ones included.

2. 
   Jencar | Dec 22, 2002 09:42pm | #11

   Quien es Mas Macho? I don't stand up to...anyway

   When we rewired our house (no ground either, disintegrating cloth covered Romex) I was the rod holder, my companion, the pounder...a jarring experience..

   We also pulled a bare wire ground through flex to the front of the house and attached it to the water main line.

   jen

3. 
   fireball | Dec 22, 2002 10:58pm | #12

   Jen,

   No offense intended,just a motivational tool.You must remember the SNL Billy Crystal skit as well.

   Barry

4. 
   Jencar | Dec 24, 2002 07:42am | #13

   I thought it was funny...Been in construction too long to be offended by much. Billy Crystal, the Golden Days of SNL, I miss em'

   Went to our local IBEW to sign up for apprenticeship, (I've enjoyed crawling under the house,running new circuits for my kitchen, etc.) I need a college Algebra course first. I've heard that commercial elec. and res. are the difference between nite and day...

   Jennifer

   Happy Holidays!! 8****8****8****8****8****8****8****8****8****8

5. 
   JohnSprung | Dec 27, 2002 02:38am | #14

   A friend of mine used to sink ground rods for TV transmitters, generally about 40 - 60 feet of 3/4" type K copper water pipe.  His method was to hammer the bottom end flat and drill a couple 1/4" holes just above the flattened part, then solder a 3/4 NPT fitting to the top end, hook it up to a hose, and let the water do all the work.

   Back to the original question, it's important to note that there are two very different things that get lumped together under the subject of grounding.  One is establishing a known standard relationship between the electrical system and true earth ground, which is what ground rods are for.  The other is establishing a low resistance connection between all the conductive parts of the electrical system and appliances that a person might touch and the neutral at the service entrance.  This is to make sure that a breaker will trip or a fuse will blow if a hot wire accidentally comes in contact with something it shouldn't.  Ground rods have nothing to do with tripping breakers or blowing fuses.  A 25 ohm ground rod tied directly to a hot at 120 volts will only pull 120/25 = 4.8 amps, not enough to trip or blow anything.  Because all the conduit and boxes are connected to neutral, we want the planet we stand on connected to neutral, too.  That way we don't get a shock from a voltage difference between true earth and anything we might touch.

   -- J.S.

3. 
   PeteKoski | Dec 19, 2002 03:29pm | #7

   One of the problems is that you have only three circuits.  That tells me that the circuits that you have are daisy chained willy nilly all over your house and that it would take nearly a half a day just to identify which circuit powers what.  Then you still would not know how they are routed.  

   This is a problem because to do it right you would need to rewire at least one of your circuits and as you can see by the first paragraph you would be led down some wild rabbit trail.  What would be frustrating about this would be that whenever you did rewire your house you would end up doing this again. This is your second best solution (the first being rewiring your house now).

    If it were my home and budgetary or other constraints kept me from rewiring now, I would do the following.  Install ground rod.  Use a drill tap and install either a ground lug or ground buss in your fuse panel.  I like ground buss because it would have two ground screws therefore having more secure ground.

   Install a junction box (somewhere between panel and computer receptacle) and run 12/2 wg from fuse panel to that jbox and also to your computer receptacle. 

   Remove one of the cables from fuse box (it is called home run and is attached to fuse and neutral buss)  and install it in Junction box. 

   Wire nut, in the j box, whites from old cable and new as well as blacks from old cable and new.  Splice and bond properly the bare wire from the new romex in the j box. 

   New romex is now terminated properly in fuse panel. 

   Install computer receptacle using your new romex.

   For all critics of this idea.  This is temporary...Right Ray?  Also in my opinion you have a safer (albeit marginally) system just in that one outlet.

    

    

   I look down my nose at people who dare to look down their nose at people.