Grounding, bonding, old swimming pool

Discussion in 'Electrical Forum discussion & Blog' started by Homeownerinburb, Feb 23, 2014.

  1. Homeownerinburb

    Homeownerinburb New Member

    Messages:
    525
    Location:
    Los Angeles, CA USA
    OK, here is another one.

    House built in the late '30s. Several additions. Pool in the back yard. Garage with rooms below opening out to pool.

    The two buildings have four, count them, four panels! Two each! What is the current main panel (and is VERY close to the pole) is a newish 200 amp affair with plenty of spaces. It has one 20 amp single pole breaker, and one 100 amp two pole breaker that feeds a (100 amp!) sub panel on the exact opposite side of the house. There is a suitable ground bond between panel one and two.

    Two also is pretty recent. But all the neutrals in this panel are bonded to the case of the panel. So I'll be addressing that. I also don't see any ground on panel two except as it is bonded to one. It certainly would do no HARM if two had a dedicated rod. I need to crack open one and see what is there.

    The second panel has a 50 amp two pole breaker that feeds an old pushmatic panel under the garage. That has eight spaces and no main breaker. Also, there is no grounding bond between the pushmatic panel and panel #2. There is not even a metallic path, as there is plastic conduit entering the pushmatic. It is 3/4" flex leaving panel two. I hate to think about it.

    The pushmatic has a 50 amp 2 pole breaker that feeds the FOURTH panel (with a bonding conductor), on the side of the building, that feeds all the pool equipment.

    I feel I must:

    Correct the neutrals bonded to ground in the 2nd panel.

    Replace the pushmatic with a modern bit of gear with ample spaces, and then create a proper ground for its main breaker and the branch circuits to see should a fault occur. I would be driving a rod and there is plumbing running underground readily to be tapped into. I appreciate that I have no bond between two and three, but there is no way that the wire is going to pull out and be replaced, and there are acres and acres of brick in the way.

    Finally, I have no clue as to what date the pool was built or what bonding requirements were applied to it. There is a jacuzzi and lights, of course. The pool equipment look pretty modern to me, but I don't care to speculate as to how well installed it is, nor if it is the 2nd set of pumps and filters.

    Question: Is it wisdom, folly or pointless to feed panel #4 from a 50 amp GFI breaker in panel three?

    And please don't beat me up over the lack of bond between two and three. I did not build it that way, and it would cost thousands to correct. I need to find a way to protect all the circuits on the outbuilding and the feed underground is just going to have to take its chances. Hell. I could replace the 50 amp breaker in #2 with a GFI, if that seemed a good bet.
  2. ankhseeker

    ankhseeker Member

    Messages:
    78
    Location:
    California
    Don't beat me up, because I am not 100% sure but It was always my understanding that the only bond was to be made at the main service panel and not at sub panels?
  3. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,285
    Location:
    Cave Creek, Arizona
    quote; there is plumbing running underground readily to be tapped into.

    You CAN bond the plumbing to a properly grounded system, but you CANNOT use the plumbing FOR a ground any longer. With the advent and proliferation of plastic plumbing lines, you, or the electric code, cannot be certain that there IS a continuous metal run for bonding purposes.
  4. Homeownerinburb

    Homeownerinburb New Member

    Messages:
    525
    Location:
    Los Angeles, CA USA
    Possibly I did not make myself clear.

    The ground buss bar and case of a sub panel are supposed to be bonded to the ground in the main panel. That is bonding.

    Of course you are correct to note that in sub panels the neutrals and grounds are to be isolated one from the other. As I noted in panel two, they are spuriously intermingled. That is high on my list to correct.

    There should be four conductors in the conduit: two hots, one neutral and one ground.

    The neutral and ground land at the same point in the main panel, but on different buss bars in the sub panel. If a third sub panel is fed from a second sub panel, the neutrals and bonds start from their respective buss bars and carry on to discrete buss bars in panel three.

    So on to panel four. If only there was a bonding path between panel two and three. But there is not and will not be.

    I will, however, keep neutral and ground isolated in panel three.
    Last edited: Feb 24, 2014
  5. Homeownerinburb

    Homeownerinburb New Member

    Messages:
    525
    Location:
    Los Angeles, CA USA
    Would your advice then be to bond to the copper (to bond the laundry and shower etc in the bonus rooms under the garage) but to drive TWO ground rods ten feet apart, in order to have confidence of a reliable ground?

    I'm happy to do it, the incremental cost is trivial. I don't own a demolition hammer, I will need to rent one to drive the rods, this is some tough ground well up the hill. It will cost me no more in the use of the hammer to do one as two or three.
  6. DonL

    DonL Jack of all trades

    Messages:
    3,812
    Location:
    Houston, TX
    The Pool pump and lighting should be on separate GFCIs.

    What do you mean by Grounding / Bonding the pool ?


    Good Luck.
    Last edited: Feb 24, 2014
  7. Homeownerinburb

    Homeownerinburb New Member

    Messages:
    525
    Location:
    Los Angeles, CA USA
    I don't actually mean to refer to grounding the pool. Modern pools, as you know better than I, are to be built to a bonding regime such that all the metal bits (diving boards, ladders, etc) be bonded to each other, and if I have this correct, to all the rebar holding the pool together. A large concrete structure with lots of rebar fully in contact with the ground is brilliantly grounded, of course.

    The electrical equipment which is remote from the pool is grounded much as any heavy equipment is: the case of the pump is bonded to ground in the panel in order that if a fault ocours, and it becomes hot, its breakers would see that and trip.

    There is MUCH more to say on the matter, I am sure, and I would not presume to lecture on the question.
    Last edited: Feb 24, 2014
  8. Homeownerinburb

    Homeownerinburb New Member

    Messages:
    525
    Location:
    Los Angeles, CA USA
    Amusing update on this project.

    The other day I took advantage of the dry weather to work in the first sub panel, which I had told you did not have a discrete, isolated neutral buss bar.

    I managed to get a closer look at the two 50 amp circuits, one for the wall oven one for the out building which has two more panels.....

    I was thinking there was no ground conductor bonding the second sub panel to the third. I was wrong.

    I had been staring at the conduit going to the wall oven and not the panel, as it happens.

    The conduit running to the third panel has the following conductors:

    Two each hots at 8 ga. One neutral at 8 ga.

    One green 12 ga conductor sort of serving as a grounding bond between the two.

    And a spare 12 ga conductor in white, sort of serving as a back up neutral.

    Why? I'd be fine with a 10 ga green bonding conductor, and the inspectors would be as well. Not so, 12 ga.

    But I did drive a ground rod near the third panel, and will be working that into the system.

    I suppose if the 50 amp breaker in panel 2 is in VERY good shape, the 12 ga wire MIGHT survive acting as the bond to alert it that there is a fault needing to be cleared. Once.
Similar Threads: Grounding bonding
Forum Title Date
Electrical Forum discussion & Blog 2 grounding/bonding questions Feb 14, 2014
Electrical Forum discussion & Blog Grounding electrode/bonding question Oct 10, 2012
Electrical Forum discussion & Blog Grounding or Bonding Jetted Bathtub May 3, 2012
Electrical Forum discussion & Blog Grounding Whirlpool Tub Motor and Heater - Bonding Panel to Electric Water Heater Feb 5, 2012
Electrical Forum discussion & Blog bonding/grounding copper pipes Nov 18, 2010

Share This Page