Thank you yet again dloki! I wish you lived in Maryland. I do not know if you are a pool builder or not but I would trust you to fix mine!
bonding vs grounding question
- Thread starter cptserious
- Start date
I am not a pool builder, EE and electrician in NJ... the pictures are of my pool remodel, I had to replace the old one which had steel walls that had collapsed inward due to age and the previous owner not keeping water in the pool.
Yikes! That is quite the fix.
Question for anyone else who may be online or knows the answer. Cleaning the deep end ladder cups and ladder itself significantly reduced the voltage. It went from 1.4 to less than 0.4 when reading from the water to the wet concrete. To non-wet concrete, it read nothing. Therefore, I cleaned the copper wires connected to the pump and SWCG and the copper wire coming from the ground near the equipment pad. I also cleaned the split bolts that hold them together. Reconnected everything but no change in voltage reading. My next test was to shut off the power to the whole house (main breaker panels). I turned them off AND turned off my generator so that it would not start. Still the same voltage reading (just a little less than 0.4).
At this point, what other suggestions would you all have? I have NOT cleaned the cups for the hand railings for the shallow end but those do not touch the water.
Question for anyone else who may be online or knows the answer. Cleaning the deep end ladder cups and ladder itself significantly reduced the voltage. It went from 1.4 to less than 0.4 when reading from the water to the wet concrete. To non-wet concrete, it read nothing. Therefore, I cleaned the copper wires connected to the pump and SWCG and the copper wire coming from the ground near the equipment pad. I also cleaned the split bolts that hold them together. Reconnected everything but no change in voltage reading. My next test was to shut off the power to the whole house (main breaker panels). I turned them off AND turned off my generator so that it would not start. Still the same voltage reading (just a little less than 0.4).
At this point, what other suggestions would you all have? I have NOT cleaned the cups for the hand railings for the shallow end but those do not touch the water.
They do. I cleaned them up really well because they were bronze after I cleaned all the white corrosion. I tightened them down pretty good so much so that I might have bent the ladder in the socket slightly. Since this post, I cleaned up 2 of the 4 shallow end railing cups and it seems to have made a small difference. I did some more testing after cleaning those cups too and I am only seeing a 0.2 voltage reading. I think I was seeing this same reading previously but because my multimeter is analog, it is not the most accurate on the 10V scale since each tick mark is 0.4 and the needle seems to be the width of 0.2 voltage readings.
What I find the most interesting is that all the power to the house was cut yet there was still stray voltage. If I have a high PPM of salt, could that affect this situation in any way, shape, form or fashion?
What I find the most interesting is that all the power to the house was cut yet there was still stray voltage. If I have a high PPM of salt, could that affect this situation in any way, shape, form or fashion?
The likely source of what you are measuring is from harmonics on the ground/neutral wire from the electric company. When you cut the main breaker off it disconnects the "hot" wires but not the neutral wire which still remains connected to the electric grid. Depending on the type of generator transfer switch it may completely isolate the neutral and the hot wires from the electric company, that may be a better way to test it.
How would I go about testing that? When I turned off the main breaker panels, I turned the generator to the off position so that it would not kick on. Is there another way to test?
Also, what is the distance from the edge of the pool out before a copper wire/grid is no longer required for proper bonding?
Also, what is the distance from the edge of the pool out before a copper wire/grid is no longer required for proper bonding?
If you have a manual transfer switch then you can switch it to the generator setting which would disconnect both L1/L2 and the neutral, if it's an automatic transfer switch there may be no way to do it... Looking at my Generac ATS I don't think it will switch over if the generator is set to off.
As far as the distance, if there is steel rebar in the concrete it needs to be a 12"x12" grid a minimum of 3 feet from the pool wall. If you bury a piece of bare #8 then you need 1 wire (loop around the pool) 18-24" from the inside edge of the pool wall and 4-6" below the subgrade (below the concrete or other finish). If you already have 3' of concrete around the pool you could try adding a bond wire around that, although not ideal some form of bonding around the pool may be better than nothing. I would bet there is a loop around the pool already there and might just be disconnected somewhere and could be easier to repair.
It is also worth noting although the 3' rule applies to the perimeter surface, any metal within 5' of the inside wall needs to be bonded including things like railings, fences, posts etc.
As far as the distance, if there is steel rebar in the concrete it needs to be a 12"x12" grid a minimum of 3 feet from the pool wall. If you bury a piece of bare #8 then you need 1 wire (loop around the pool) 18-24" from the inside edge of the pool wall and 4-6" below the subgrade (below the concrete or other finish). If you already have 3' of concrete around the pool you could try adding a bond wire around that, although not ideal some form of bonding around the pool may be better than nothing. I would bet there is a loop around the pool already there and might just be disconnected somewhere and could be easier to repair.
It is also worth noting although the 3' rule applies to the perimeter surface, any metal within 5' of the inside wall needs to be bonded including things like railings, fences, posts etc.
Funny enough, I too have a Generac ATS. However, my pool panel is not hooked up to the generator and when I switched it to off and killed the power, it never switched over.
I think this is where the residual voltage is originating. I need to measure how far from the pool wall it is but we had new concrete laid down and tied into existing concrete with rebar. The rebar was drilled in 4-6" but no bonding wire was attached to this new set of rebar. The only thing is that I do not know what is under or in the existing concrete deck. I do not know if they put a 12"x12" grid or if they just laid concrete without rebar. I do know that within the pool wall itself, there are 30 20' #3 rebar as steel reinforcement that I bet have to be tied to an existing bonding grid/wire which is what is probably coming out at the equipment pad. Those drawings were from the original owner who kept them and passed them to the previous owner. The one thing that I can't understand though is this wording in the features and benefits of a desjoyaux pool. It says, "A wall like no other! Concrete reinforced stell with the active casing built-in." and "48" wall system 15% larger giving your 5 extra inches of water in your play area." Does this mean that the walls of the pool are 4 feet thick?!
I think this is where the residual voltage is originating. I need to measure how far from the pool wall it is but we had new concrete laid down and tied into existing concrete with rebar. The rebar was drilled in 4-6" but no bonding wire was attached to this new set of rebar. The only thing is that I do not know what is under or in the existing concrete deck. I do not know if they put a 12"x12" grid or if they just laid concrete without rebar. I do know that within the pool wall itself, there are 30 20' #3 rebar as steel reinforcement that I bet have to be tied to an existing bonding grid/wire which is what is probably coming out at the equipment pad. Those drawings were from the original owner who kept them and passed them to the previous owner. The one thing that I can't understand though is this wording in the features and benefits of a desjoyaux pool. It says, "A wall like no other! Concrete reinforced stell with the active casing built-in." and "48" wall system 15% larger giving your 5 extra inches of water in your play area." Does this mean that the walls of the pool are 4 feet thick?!
Okay, so this is where I stand. Finally finished cleaning the railing cups in the shallow end. Now, everything is clean with good tight connections on the visible part. I even cleaned the copper at the equipment pad as well as the split bolts and put them back together (SWCG and pump are now both connected to the copper wire coming out of the ground at the equipment pad). Still reading between 0.2 and 0.4 volts when pool deck concrete is wet and put one meter end in the water and touch the other end to the wet concrete. The rebar that was put in to secure the new concrete to the old concrete is no less than 39" from the pool wall. However, that rebar was NOT connected to the bonding grid when it was installed. There is still a ground rod driven into the earth next to my equipment pad that I have not been able to remove, yet.
Three questions.
1) Could the grounding rod that was "installed" by the electrician who came out be causing any issues?
2) Could the connections of the pump and SWCG to the bonding grid within 6" of each other cause any issues?
3) Could having a high PPM of salt cause any issues?
My suspicion is that I will need to cut a channel about an inch wide in the new concrete, connect the new rebar to a new #8 bare copper wire, connect that new copper wire to the existing copper wire at the equipment pad, and bury it 4"-6" below grade. Would this be an accurate assessment given the voltage reading we are still getting? What would be the long term implications of this should people swim? Would the bonding grid not fully work because of the rebar in the new concrete and thus potentially allow high voltages to enter the "area" causing possibly hazardous shocking potential?
Three questions.
1) Could the grounding rod that was "installed" by the electrician who came out be causing any issues?
2) Could the connections of the pump and SWCG to the bonding grid within 6" of each other cause any issues?
3) Could having a high PPM of salt cause any issues?
My suspicion is that I will need to cut a channel about an inch wide in the new concrete, connect the new rebar to a new #8 bare copper wire, connect that new copper wire to the existing copper wire at the equipment pad, and bury it 4"-6" below grade. Would this be an accurate assessment given the voltage reading we are still getting? What would be the long term implications of this should people swim? Would the bonding grid not fully work because of the rebar in the new concrete and thus potentially allow high voltages to enter the "area" causing possibly hazardous shocking potential?
Okay, so I disconnected the light in the pool completely and am still getting the same VAC reading. However, if the bonding grid is completely intact and working properly then there should never be a reading. Is that correct? Is it possible to have everything bonded properly but still see VAC readings from the water to the concrete pool deck?
Huzzah! I may have found the problem and need to know what the fix could be.
I turned the breaker off at the main panel in the garage, unhooked all hot wires from the breaker switches at the pool panel, unhooked the neutral coming from the main panel to the pool panel and ran a test. I was still getting the 0.2-0.4 VAC reading. Disconnected the ground coming from the main panel to the pool panel and ran other test. Voila! No more VAC reading.
Now, should the bonding grid/wire have stopped this or is this simply a grounding issue that an electrician should be able to remedy?
I turned the breaker off at the main panel in the garage, unhooked all hot wires from the breaker switches at the pool panel, unhooked the neutral coming from the main panel to the pool panel and ran a test. I was still getting the 0.2-0.4 VAC reading. Disconnected the ground coming from the main panel to the pool panel and ran other test. Voila! No more VAC reading.
Now, should the bonding grid/wire have stopped this or is this simply a grounding issue that an electrician should be able to remedy?
Is that second ground rod still installed?
If so, how far is it from the main ground rod?
Also, are the two of them connected together?
If so, how far is it from the main ground rod?
Also, are the two of them connected together?
Yes, I was not successful in digging it up. That sucker is in there good.
If the main ground rod is anywhere near my main panels in the garage then it is about 150'.
No, they are not connected together because that second ground rod was installed by the electrician about a week ago and no new wiring was installed except for the wire from the ground rod to the neutral bar (which is still baffling me as to why he did that).
I bet you are thinking that if I connect the ground bar in the sub-panel to the ground rod then the VAC reading will go away. Am I right?
If the main ground rod is anywhere near my main panels in the garage then it is about 150'.
No, they are not connected together because that second ground rod was installed by the electrician about a week ago and no new wiring was installed except for the wire from the ground rod to the neutral bar (which is still baffling me as to why he did that).
I bet you are thinking that if I connect the ground bar in the sub-panel to the ground rod then the VAC reading will go away. Am I right?
There should not be a second ground rod, but since there is it should be connected to the ground bar and not the neutral bus. So I'd change that first and take your voltage readings again.
Will do! I need to get an adapter first because the electrician used #6 AWG wiring but the ground bar in the sub-panel looks like it only supports up to #10.
Could this second ground rod be causing that little bit of extra voltage or is there a wiring issue with the ground since removing the main panel ground from the sub panel ground bar removed the voltage reading?
Could this second ground rod be causing that little bit of extra voltage or is there a wiring issue with the ground since removing the main panel ground from the sub panel ground bar removed the voltage reading?
It's hard to say, but connecting the ground rods together should remove the potential if that is the problem.
Last question... for now I think.
If the main hot wires at the sub panel are turned off at the main panel by the breaker and the neutral wire is disconnected from the sub panel, should there be any voltage on the ground wire coming from the main panel? Is that a potential wiring fault?
If the main hot wires at the sub panel are turned off at the main panel by the breaker and the neutral wire is disconnected from the sub panel, should there be any voltage on the ground wire coming from the main panel? Is that a potential wiring fault?
The earth can have residual voltage potential between two points and with the ground rods so far apart and not connected, you could have a small potential between them. Connecting them together should lessen the potential to almost zero.