Multiple splices in GEC

[richardmoore]

Gentlemen?and ladies?

I?m one of those dastardly home inspectors. At the risk of incurring your wrath I have a question. Basically it's: How many splices are you comfortable with for a GEC between the panel and ground rod?

Here?s the situation: 1907 house that had the wiring partially updated in the 70?s. This included a ?modern? 200 amp service panel. Grounding was accomplished with a #4 conductor to the water pipe entrance. Then in 1987 a ?carriage house? with separate living quarters was built at the street connected to the main house by a 30? breezeway. There are now two service drops to the property, two meters etc. Both service panels are now in the garage of the addition, one a normal distribution panel serving the carriage house, the other just a single 200 amp disconnect for the main house. Both of these are connected to a single ground rod. Three insulated feeders (2 hot, 1 neutral) are then run from the disconnect. through metallic conduit to a new ?service? mast at the back of the garage, overhead (30+ foot span with a bare support cable) to the ?original? service mast at the main house, through the old meter base and to the panel which is now a sub-panel. This panel had a new ground bar added, the bonding strap disconnected, and the grounds and neutrals separated?all correct. The conductor to the water piping was abandoned at the panel (no bonding at present other than by accidental contact between this original GEC and other grounding conductors).

So now the grounding electrode is about 100 feet away and the effective GEC is a mishmash of conduit, support wire, and jumpers. While all connections look like they have been made correctly with appropriate fittings and jumpers I sure would have been happier seeing a continuous bare fourth conductor run between the disconnect and panel. While I didn?t report this as wrong (it seems to be allowed) I did recommend that the client get an evaluation of this ?GEC? from the electrician while he?s there fixing the other problems. If the water piping is bonded (as per my recommendation) it seems that that would become the path of least resistance and would once again effectively be the grounding electrode.

I?m not asking for an evaluation of this particular installation (that is hopefully going to be done) so much as your general thoughts on this for my own illumination.

Richard Moore
Seattle, WA

[ January 20, 2004, 02:53 PM: Message edited by: richardmoore ]

 

[iwire]

Re: Multiple splices in GEC

So now the grounding electrode is about 100 feet away and the effective GEC is a mishmash of conduit, support wire, and jumpers.

That is not the GEC, that is an EGC and there are no requirements as to the number of splices in an EGC.

The conductor to the water piping was abandoned at the panel (no bonding at present other than by accidental contact between this original GEC and other grounding conductors).

This conductor is a GEC and must be reconnected to the panels grounding bar.

I agree that an electrician should look over this installation to take care of grounding and bonding issues.

 

[hurk27]

Re: Multiple splices in GEC

Three insulated feeders (2 hot, 1 neutral) are then run from the disconnect. through metallic conduit to a new ?service? mast at the back of the garage, overhead (30+ foot span with a bare support cable) to the ?original? service mast at the main house,

the panel which is now a sub-panel. This panel had a new ground bar added, the bonding strap disconnected, and the grounds and neutrals separated ?all correct.

This I am worried about as now there is no effictive fault path even if the water pipe is restored there shoule be a 4th returne wire ran between the disconnect and the sub-panel as it is now the branch circuits land on a ground bar in this sub-panel that does not have any connection to the neutral while this is preferred way there has to be a path back to the neutral. Earth grounding will not provide this path as the resistance is way to high. think about it even at the 25 ohms the code allows as min. the amount of current it would pass is only 4.8 amps at 120 volts this would not fault a 15 amp breaker!
If anything in this house ever went to ground right now, all the grounding including the panel case would be at a 120 volt potential to earth, and will be a shock hazared!
There has to be a path to the service neutral.
THIS NEED'S TO BE REPAIRED ASAP!!!

This is one of those set ups that a code inforcement could step in and make this happen as it is dangerous to human life or property, And need attention ASAP.

 

[iwire]

Re: Multiple splices in GEC

Wayne I am not so sure it does not have a grounding conductor.

Three insulated feeders (2 hot, 1 neutral) are then run from the disconnect. through metallic conduit to a new ?service? mast at the back of the garage, overhead (30+ foot span with a bare support cable)

The metallic conduit could certainly be the EGC, the bare messenger could be the EGC for the overhead.

Hard to say not seeing it ourselves, if the installer knew enough to separate the grounding and grounded conductors at the old service I would hope they new enough to run a EGC.

[ January 19, 2004, 04:57 PM: Message edited by: iwire ]

 

[jxofaltrds]

Re: Multiple splices in GEC

Richard

Since this is "this for my own illumination."

I'll give you a bye (sp?).(a bye like in sports---not a good bye)

There is no way to answer your question via the net. There are to many variables that would change "our" answers.

Mike P.

[ January 19, 2004, 06:10 PM: Message edited by: jxofaltrds ]

 

[hurk27]

Re: Multiple splices in GEC

(30+ foot span with a bare support cable)

So now the grounding electrode is about 100 feet away and the effective GEC is a mishmash of conduit, support wire, and jumpers. While all connections look like they have been made correctly with appropriate fittings and jumpers I sure would have been happier seeing a continuous bare fourth conductor run between the disconnect and panel.

Bob I see now where there must be a clamp on both risers that they bonded the bare messenger wire to. but I don't like it as a fault current path as how many times have we seen these clamps corrode and loose connection? Would we trust this for a neutral connection (that made my hair stand up)

250.90 General.
Bonding shall be provided where necessary to ensure electrical continuity and the capacity to conduct safely any fault current likely to be imposed.


Maybe some one else would know of a NEC article that might prohibit this.
As it make no sense that a GEC has to be continuous but a EGC does not when it is there for fault current. Which would provide a higher level of safety? Without the GEC you have a chance of getting struck by lightning. Without the EGC you have a chance of having a short circuit that would heat up everything connected to the grounding to a 120 volt potential.

[ January 19, 2004, 08:59 PM: Message edited by: hurk27 ]

 

[hurk27]

Re: Multiple splices in GEC

Richard I guess that I would contact the local AHJ and see what he thinks. There are a few here on this forum that are from WA. maybe they could give you some insight to what to do, as it doesn't sound like a good installation to me.

 

[richardmoore]

Re: Multiple splices in GEC

Thanks guys...

I had already deferred analysis to a Sparky as this was beyond my comfort level and will likely remain that way. Just trying to fill a few empty neurons.

Richard

 

[iwire]

Re: Multiple splices in GEC

Originally posted by hurk27:
As it make no sense that a GEC has to be continuous but a EGC does not when it is there for fault current. Which would provide a higher level of safety? Without the GEC you have a chance of getting struck by lightning. Without the EGC you have a chance of having a short circuit that would heat up everything connected to the grounding to a 120 volt potential.

I follow you Wayne but a requirement for a continuous EGC would be a bit of a pain in the you know what.

Would you make it for feeder EGCs only?

Even still that would make the use of a cable system changing to a raceway system out of the question.

For the above installation I am with you a EGC conductor would make more sense then a clamp to the riser.