Electricians and engineers list some common mistakes in grounding and bonding pools<\/p>\n
Grounding and bonding can be one of the most confusing parts of pool construction.<\/p>\n
So when pool professional and licensed electrician Alan Brotz brings on a new crew member, his first message is very clear: Know your stuff.<\/p>\n
\u201cI tell all my guys there is no more important wire on a pool or spa wiring system than a ground wire and a bond wire,\u201d says the owner\/president of Swim Systems Inc.<\/a> in Oviedo, Fla. \u201cThe grounding and bonding around a pool are more critical than in any other application in a home, because of the conductivity of water.\u201d<\/p>\n This message applies to pool contractors. Even if local codes require that a licensed electrician handle this critical stage of construction, it\u2019s valuable to know how bonding and grounding should be done.<\/p>\n Here are six common mistakes made by both pool professionals and electricians while grounding and bonding pools, and some guidelines on how to avoid them.<\/p>\n Mistake #1: Confusing the two<\/span><\/strong><\/strong><\/p>\n But the two are quite different.<\/p>\n Grounding is a process meant to protect people against a possible fault in the electrical system. Basically, it means to electrically attach a piece of equipment to earth ground, which is at the lowest \u201celectrical potential,\u201d mostly referred to as 0 Volt potential. If there\u2019s a fault, or short, the circuit breaker will trip and turn off the equipment.<\/p>\n To ground a piece of equipment, installers must run a properly sized wire from the equipment, through the same conduit as the current-carrying conductors and to the circuit breaker panel. Finally, the wire attaches to the ground bus bar in the circuit breaker panel.<\/p>\n Bonding, on the other hand, electrically ties all specified metallic elements together to minimize the differences in voltage. (In these discussions, voltage is also referred to as potential.) The pump, motor, ladder, even the water nowadays, are bonded.<\/p>\n \u201cIf there\u2019s a difference in potential, that creates a foundation for current flow,\u201d Brotz says. \u201cIf the current can flow between two pieces of equipment, then it\u2019s just waiting for somebody to come along and be the conductor.\u201d<\/p>\n Brotz gives the example of a pump and heat pump sitting next to each other, with neither bonded. \u201cIf there was a fault in the system, either in the pump or heat pump, it\u2019s possible for either piece of equipment to become energized with a voltage other than 0 volts,\u201d he says. \u201cIf somebody were to come up and touch the pump, then they become the conductor between the two and get shocked or electrocuted.\u201d<\/p>\n To bond the system, a No. 8 wire runs from one metallic element to the next, connecting to pieces of equipment on a provided bonding lug and, thus, creating an electrical bonding grid. The wire runs through the earth, not inside a conduit.<\/p>\n Mistake #2: Neglecting to ground and bond thoroughly<\/span><\/strong><\/strong><\/p>\n Other installers take care to do this with all the pool equipment, but then forget about less obvious things like fences or ladders.<\/p>\n To be clear, anything metallic within 5 feet of the water (meaning the inside wall of the pool), must be bonded. This includes the back of the light niche, ladders (both ladder pockets), diving board stands, lifeguard stands, handrails, junction boxes, pool shells and deck, if they\u2019re made of conductive material. There are exceptions: Any small isolated parts of less than 4 inches in any dimension and extending less than 1 inch into the structure, such as rope hangers.<\/p>\n The pool\u2019s rebar must also be bonded, as well as any reinforcing steel under the deck within 3 feet of the inside of the pool wall. If there is no reinforcing steel in the deck, at least one bare No. 8 (or larger) buried wire may be used, if installed in accordance with code requirements.<\/p>\n Generally speaking, all electrical equipment associated with the pool must be grounded.<\/p>\n Mistake #3: Grounding and bonding to earth<\/span><\/strong><\/p>\n Any defective piece of equipment will remain energized. \u201cThen when somebody comes up and touches it, it\u2019s, \u2018Good night, nurse.\u2019\u201d Brotz says. \u201cThat ground rod will do absolutely nothing.\u201d<\/p>\n Some will even try using the earth as part of the bonding conductor. \u201cIn other words, you bond the pool together, drive a ground rod; bond the pad together, drive a ground rod. But you don\u2019t run a wire in between,\u201d says E.P. Hamilton III, Ph.D., P.E., an electrical engineer and president of Hamilton & Associates<\/a> in Pflugerville, Texas. If you do this, the system isn\u2019t bonded, because everything must be tied together. Otherwise, you risk current straying, if the potential between two components is different.<\/p>\n Mistake #4: Using the wrong connectors<\/span><\/strong> That\u2019s why tying or wrapping the wire around a bolt or other metallic component on the equipment won\u2019t do the trick. \u201cIt doesn\u2019t insure any sort of reasonable electrical contact, particularly over time,\u201d Hamilton says.<\/p>\n Instead, use clamps or lugs rated for the specific wire size and application. For instance, when connecting the wire to the pool\u2019s rebar grid, you must use clamps that are UL approved for concrete encasement. If they\u2019re going in the ground, the tag should indicate that they are approved for direct burial. These clamps are usually made of brass and copper. The screw should be made of stainless steel or brass. You don\u2019t want plated steel anywhere near these applications, or they will rust and eventually fail.<\/p>\n \u201cAs to ones that are not required within concrete, then they\u2019re going to be standard electrical fittings like you would get at an electric supply house,\u201d Hamilton says.<\/p>\n Make sure the connectors are listed for the type of wire you\u2019re using, whether it\u2019s stranded or solid. Electrician and pool professional David Durkin often sees stake-ons, bud connectors and terminals used with solid wire. \u201cThey will become loose after a while, because it\u2019s supposed to mesh in, and you can\u2019t mesh into a solid wire,\u201d says the owner of D&M Electric<\/a> in Antioch, Calif.<\/p>\n Conversely, you can\u2019t wrap stranded wire around a screw. \u201cIt keeps pushing out strands, and it\u2019s not a good connection,\u201d Durkin says. \u201cThey should be using terminals.\u201d<\/p>\n If you do want to make the connection by wrapping solid wire around a screw, wrap it clockwise, he adds. \u201cWhen the screw tightens, it sucks the wire instead of pushing it out.\u201d<\/p>\n When you have to pot certain connections, such as those inside a light niche, use potting kits made for that purpose. Don\u2019t use things such as bath tub caulk, Hamilton says.<\/p>\n Mistake #5: Using the wrong wires<\/span><\/strong> There is one place where you must use an insulated wire: \u201cIf you have a non-metallic conduit going from the light niche up to the junction box, you have to pull an insulated No. 8 green wire through there,\u201d Hamilton says. \u201cBut even that\u2019s more of a ground wire, even though it does have some involvement in the bonding system.\u201d<\/p>\n Many codes require that No. 8 wires and smaller be solid. If you\u2019re cautious by nature, use solid wires for No. 6 as well. \u201cIf you need a wire that\u2019s that small, you\u2019re better off with a solid wire, just because the strands are more susceptible to environmental damage,\u201d Hamilton says.<\/p>\n This is especially important with bond wires, since they\u2019re in direct contact with the earth. \u201cIt may be buried 50 or 60 years,\u201d Hamilton says.<\/p>\n Mistake #6: Believing that plastic or fiberglass elements need bonding<\/span><\/strong> \u201cDon\u2019t do anything to the tension band on that filter,\u201d Hamilton says. \u201cThat creates a substantial safety hazard\u2026if you do anything to the tension band. You\u2019re affecting its mechanical integrity and ability to hold the filter together over time and under pressure.\u201d<\/p>\n If that filter comes with a bonding lug, or has a metallic base with a bonding lug, then it must be bonded. But if it\u2019s all polymer on a polymer base and it comes with no bonding lug, then it doesn\u2019t need to be included in the grid.<\/p>\n Explain to the inspector that, because the band is only touching the plastic filter shell, there is no electrical connection. If the inspector won\u2019t budge, then move the equipment so it\u2019s more than 5 feet away from the inside wall of the pool.<\/p>\n You may have the same problem with plastic lights outfitted with an all-plastic niche. Show the inspector that UL has listed it to go ungrounded.<\/p>\n Take a slightly different path when installing double-insulated pumps, Hamilton says. Though you can\u2019t bond them now, code requires that you run a bonding wire to it anyway. You won\u2019t make the connection to the pump, but you must connect the bond wire to the ground wire in the junction box serving the pump. The code requires this so that if the double-insulated pump is replaced with a pump that isn\u2019t double-insulated, then there\u2019s a place to bond it without tearing up the pool area.<\/p>\n Source: Rebecca Robledo – Pool and Spa News | 5.13.2009<\/strong><\/p>\n","protected":false},"excerpt":{"rendered":" Electricians and engineers list some common mistakes in grounding and bonding pools Grounding and bonding can be one of the most confusing parts of pool construction. So when pool professional and licensed electrician Alan Brotz brings on a new crew … Continue reading
\n<\/strong>Many pool professionals don\u2019t know the difference between grounding and bonding, while others use the terms interchangeably. Even some electricians make this mistake, Brotz says.<\/p>\n
\n<\/strong>Because of confusion between the two terms, some professionals may ground but not bond, or vice versa.<\/p>\n
\n<\/strong>Some professionals believe that grounding can be done by driving an 8-foot ground rod into the earth and hooking the grounding wire to it. \u201cThat will not conduct fault current to trip the circuit breaker,\u201d Brotz says. Some may believe this sends any stray current to the earth, but that\u2019s not the purpose of grounding.<\/p>\n
\nWhen hooking up the bonding and grounding wires to a piece of equipment, you want the best connection possible to ensure that any current that needs to move has a clear path.<\/p>\n
\nWatch where you use insulated wire. Particularly on the equipotential grid under the deck, uninsulated wire is mandated by code. Some electricians prefer this variety on the whole bonding grid to maximize contact with all relevant pieces of equipment, the water, earth and all conducting surfaces in contact with the bond wire.<\/p>\n
\nThis mistake is generally not made by professionals, but rather by inspectors. Many of them, for instance, see the metal tension band on a plastic or fiberglass filter and insist that it be bonded.<\/p>\n