b) lifegaurd shack/toilet/concession stand 20 cir 1 ph panel
I understand (assume) this panel to supply 120 V and possibly 240 V loads.
To me, Sparky is describing a 120 / 240 Volt 3 Ø 4 wire PoCo transformer bank with two service laterals, one 120 / 240 volt 1 Ø 3 wire, and one 240 volt 3 Ø 3 wire.
But since the question is about objectionable current, maybe that 3 Ø lateral is 120 / 240 V 4 wire? What say, Sparky?
As to the question. . .I personally object to the neutral current finding multiple return paths between the (in this case) two service neutral / ground bonding points and the transformer neutral terminal. . .but what's a code compliant sparky to do ??? And the chain link conductor makes the question all the more poignant.
[This message has been edited by ElectricAL (edited 07-12-2003).]
Re: Objectionable current #85502 07/13/0308:00 PM07/13/0308:00 PM
Did you mean to say that one of the phases was grounded or that the center tap of one of the transformers was grounded? If one of the phases was grounded then this would be a corner grounded delta system and the only voltage available at either panel would be 240V.
When you say there is a noticeable voltage on the fence do you mean you can feel it when the pump is on or your reading it with a tester? Assuming this is not a corner grounded delta system connecting any loads such as the pump that do not use the grounded conductor should not have any effect on the current flow seen on the water piping or fence.
Re: Objectionable current #85504 07/13/0309:33 PM07/13/0309:33 PM
I woke up thinking about open wye - open delta transformer banks this morning, as well as a neighbor's open neutral.
Both of these will contribute neutral current to the grounding electrode systems of the concession stand and the pump building.
And also, the PoCo distribution grid primary unbalance current will be using the GES. The neutral to the buildings will be bonded by the PoCo at the transformer to the distribution grid neutral, if present.
So, I have a couple of questions. . .
1. Are there two (or three) PoCo primary (high voltage) conductors connected to the transformer primary windings?
2. What are the neighbors like?
Re. 1.: If there are only two high voltage conductors, the primary windings will be configured as an open wye. The wye neutral current will seek all available return paths to the generator (or substation), including the municipal water system.
Re. 2.: A neighbor with an open neutral and an unbalanced load will contribute to the current on the municipal water system. Depending on how your PoCo interconnects secondary neutrals between transformers, that neighbor's unbalance current likely is travelling from his neutral GES bond to the water pipe to the pool pump house service neutral to the pole to pole neutral that gets back to the neighbor's transformer.
Most PoCos make the secondary neutral (that they install from pole to pole) do triple duty as the primary neutral and as the interconnection of all their pole grounds (butt plates, ground balls, guy wire anchors, etc.).