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  1. #1
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    Default Service Drop Question!

    Seems like I recall hearing in a recent electrical seminar that the older three wire individual service conductor service drop is considered to be obsolete, and when found during an inspection, should be called out for replacement with the more modern triplex cable. Is this true or not? Will an electrical utility company automatically do the upgrade installation if asked about it? Thanks in advance for your input!

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  2. #2
    Join Date
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    Default Re: Service Drop Question!

    These conductors are the property of the serving utility. The only time I have seen them changed was due to a failure of a conductor or possibly when a service was increased and a new triplex was run due to inadequate size on the existing drop.

    Is this really in the scope of a home inspection?


  3. #3
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    Default Re: Service Drop Question!

    Michael,

    I've not heard of that.

    Jim,

    If it is a hazard (or the inspector perceives it to be a hazard), then, yes, it is within the scope of the home inspection.

    Jerry Peck, Construction / Litigation Consultant
    Construction Litigation Consultants, LLC ( www.ConstructionLitigationConsultants.com )
    www.AskCodeMan.com

  4. #4
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    Default Re: Service Drop Question!

    Quote Originally Posted by Michael Chambers View Post
    Seems like I recall hearing in a recent electrical seminar that the older three wire individual service conductor service drop is considered to be obsolete, and when found during an inspection, should be called out for replacement with the more modern triplex cable. Is this true or not? Will an electrical utility company automatically do the upgrade installation if asked about it? Thanks in advance for your input!
    I only talk about the service drop when there are problems. Damaged insulation, too close tot the roof, damaged/loose anchors. As Jim said, the service drop belongs to the utility.

    Department of Redundancy Department
    http://www.FullCircleInspect.com/

  5. #5
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    Default Re: Service Drop Question!

    Quote Originally Posted by Gunnar Alquist View Post
    I only talk about the service drop when there are problems. .........................................
    And that's exactly why I asked the question - in order to determine whether or not a three wire individual service conductor service drop is a problem. From everybody's responses, it seems that it is not. Thanks again to all for your input!

    (By the way, yes, a HI should be looking at the service drop coming to the house. There are several hazardous conditions that can be spotted, and should be included in your report; i.e. lines through trees, improper clearances, broken conductors, frayed or missing insulation, etc., etc.)

    Last edited by Michael Chambers; 11-28-2009 at 02:17 PM. Reason: Clarification.

  6. #6
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    Default Re: Service Drop Question!

    Quote Originally Posted by Michael Chambers View Post
    (By the way, yes, a HI should be looking at the service drop coming to the house. There are several hazardous conditions that can be spotted, and should be included in your report; i.e. lines through trees, improper clearances, broken conductors, frayed or missing insulation, etc., etc.)
    Absolutely.

    Department of Redundancy Department
    http://www.FullCircleInspect.com/

  7. #7
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    Default Re: Service Drop Question!

    I do a lot of service upgrades. One thing I frequently find where the old 3 wire overhead is used is knobs (insulators) screwed into the roof decking. People seldom make the effort to remove and reinstall these knobs (often you can't without involving the utility or an electrician) when installing a new roof. Consequently, water gets in around the knobs and penetrates to the decking, and often beyond. Long story short, there is often significant damage in the vicinity of these knobs covered up by the roofing material.


  8. #8
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    Default Re: Service Drop Question!

    Bill,

    Your post brings up an interesting question: If the knobs are screwed into the roof sheathing, weren't the overhead service drop conductors too close to, and too low over, the roof?

    Jerry Peck, Construction / Litigation Consultant
    Construction Litigation Consultants, LLC ( www.ConstructionLitigationConsultants.com )
    www.AskCodeMan.com

  9. #9
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    Default Re: Service Drop Question!

    I don't deal with what was permitted prior to current code very often so I can't really address whether any of this was permitted in prior code cycles.

    But, in most jurisdictions the point of service is where the NEC starts and whatever the utility wants/does ends. In most places, the point of service is where the utility's overhead is spliced into the service conductors to the meter, and this is usually after the knob(s) the overhead is attached to.

    So, what you have is a situation where the AHJs and the utility say the NEC doesn't apply to the overhead because it belongs to the utility, so the knobs mounted to the roof are perfectly acceptable. But, the same method of feeding a garage, for example, wouldn't fly because the NEC applies. And, in fact, I frequently find a mast mounted fairly close to the roof knobs for this very reason. The other part of this is that you do things like the utility wants it done or they don't attach - it's apparently been to court here and the utility won

    Roof knobs fly in the face of the current wording (18 inch minimum under some circumstances) and at least several cycles back - BUT, and again not my preference for how stuff gets done, it was commonly done apparently with the blessings of all concerned. Roof mounted knobs aren't permitted any more in the areas where I work, but it is a rule the utilities have instituted themselves.

    It is worth calling it out if there is roof damage or if the overhead clearances are an issue (with sag you can easily touch some with a shovel handle). In most places the utility won't do anything about it unless there is a service upgrade - where a mast attachment would normally be required.

    I have gone to great lengths to place new services and masts to limit the overhead running across more than a few inches of a roof only to have the utility decide the overhead is better placed somewhere else and cross many feet of roof at a 2 to 6 foot clearance. AHJs don't seem to have an issue with it and I have no control over it.

    Book says no but it doesn't seem to matter as it's not work the electrician normally does.

    I can drive for 30 minutes in any direction and find several hundred houses with roof mounted knobs. Doesn't make it right. They do seem to have a better track record of not being pulled out by ice, even with bad decking, than a wall mounted knob does, for whatever that's worth.


  10. #10
    Fred Warner's Avatar
    Fred Warner Guest

    Default Re: Service Drop Question!

    Most Municipal Electrics and Pocos require that the weatherhead be even or above the POA. This rule alone would negate any screwpoint lags in the roof when using SE cable. The picture shown shows the weatherhead below the point of attachment.


  11. #11
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    Default Re: Service Drop Question!

    Quote Originally Posted by Fred Warner View Post
    Most Municipal Electrics and Pocos require that the weatherhead be even or above the POA. This rule alone would negate any screwpoint lags in the roof when using SE cable. The picture shown shows the weatherhead below the point of attachment.
    That requirement is also in the NEC.


  12. #12
    Cobra Cook's Avatar
    Cobra Cook Guest

    Smile Re: Service Drop Question!

    The service drop to the home or business is of course a part of a home inspection. But is mostly limited to the mast, drip loop and means of attachment to the home. I'm sure that if it is loose and leaning a simple call to the utility company about it they would be glad to come and fix it.


  13. #13
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    Post Re: Service Drop Question!

    Michael, that is a great photo, and a great question. A visual inspection of the service drop is always a good idea when performing a home inspection. In your photo, two things stand out to me: 1) the conductors appear to be properly sized for what is likely a 100 Amp main disconnect; 2) the insulation on the conductors appears to be in good condition. In a situation where either of those circumstances are not the case, it is worth mentioning. In Michigan, the electric utility company will determine the size of the conductor (and they frequently under-size them). It is rare that a new installation will be individual conductors, but I have seen it. That would answer the question about obsolescence of individual conductor service drops. The triplex cabling is more common, as it is faster - and easier - to connect a service with triplex. Utilities are not always quick to replace single conductor service drops, even when the insulation is crumbling. In one case, it took them three years. They even went to the trouble to put rubber boots on the conductors four feet out from the mast weatherhead for a roof replacement job, rather than replace the bare (yes, all three, and copper, too!) conductors.


    Randall Aldering GHI BAOM MSM
    Housesmithe Inspection
    www.housesmithe.com

  14. #14
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    Default Re: Service Drop Question!

    Thanks Randy. The house actually had an old split-buss 60 amp service, which I suggested should be up-graded. This is pretty typical for the older sections of St. Louis. You are correct however, in that the service drop was in pretty good condition.

    The explanation I heard about individual service conductors was that triplex cable is a physically stronger means of bringing the service drop to a house. The cable-like neutral conductor adds support and strength to the two 120 volt conductors.

    Your mention of individual service conductors with missing insulation reminded me of an episode we had at our house about 20 years ago. We had the individual conductors with some insulation missing, and a couple of them found each other one windy day. It didn't catch the house on fire, but we had the fire department there, my wife ran out bare-footed, stepping on melted insulation in the yard, and ended up in the emergency room, etc. It was quite a deal at the time.

    Thanks again for your input.


  15. #15
    John Steinke's Avatar
    John Steinke Guest

    Default Re: Service Drop Question!

    Whoever told you that was suffering an excess of opinion, and a shortage of knowledge.

    I say this because utilities, especially on the West Coast, put in millions of miles of defective triplex, that they're trying to replace as fast as they can.

    What is a concern when you see such a service drop is: how big is the service? If there's a 200-amp main breaker at the end of those little wires, it's a good bet that the panel was changed without a permit, and has other issues as well.

    Likewise, the manner of anchoring those old drops is no longer considered adequate, and needs to be looked at to see if it's pulling free. Note I said "LOOKED at." Do it from the ground with binoculars; gon't go anywhere near those wires.


  16. #16
    Fred Warner's Avatar
    Fred Warner Guest

    Default Re: Service Drop Question!

    Quote Originally Posted by John Steinke View Post
    Whoever told you that was suffering an excess of opinion, and a shortage of knowledge.

    I say this because utilities, especially on the West Coast, put in millions of miles of defective triplex, that they're trying to replace as fast as they can.

    What is a concern when you see such a service drop is: how big is the service? If there's a 200-amp main breaker at the end of those little wires, it's a good bet that the panel was changed without a permit, and has other issues as well.

    Likewise, the manner of anchoring those old drops is no longer considered adequate, and needs to be looked at to see if it's pulling free. Note I said "LOOKED at." Do it from the ground with binoculars; gon't go anywhere near those wires.
    I'm trying to fathom the math involved in the above statement.
    If I were to allow an average of 140 feet for a triplex service drop span, than it follows that one mile of triplex cable would service approximately 37 homes. One million miles of triplex would service 37 million homes and the figure "million(s)" - the "s" making the problem in the plural - would dictate that at least 74 million homes on the West Coast are being re-wired because of defective triplex.
    Why haven't I heard of this job boom? Is this part of the "Stimulus Plan"?


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