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#91
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#92
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and ONLY if there is no DC current leakage, or DC grounds wired to the AC
grounds. Of course, this NEVER happens. ;-) -- Keith __ Pardon my driving, I'm reloading. "John R Weiss" wrote in message news:%D8vc.3368$sI.620@attbi_s52... "Paul Schilter" paulschilter@comcast,dot,net wrote... You don't have to install a GFCI in every outlet. Just in the first outlet of the circuit, the rest that are downstream will be protected. Just have them in every circuit. ONLY if the GFCI outlet supports chaining, and ONLY if it is the first outlet in the circuit and ONLY if it (the circuit and the GFCI) is wired correctly! |
#93
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![]() "John R Weiss" wrote in message news:%D8vc.3368$sI.620@attbi_s52... "Paul Schilter" paulschilter@comcast,dot,net wrote... You don't have to install a GFCI in every outlet. Just in the first outlet of the circuit, the rest that are downstream will be protected. ONLY if the GFCI outlet supports chaining, Most do. In fact, I can't recall seeing any in the last 20 years that didn't. and ONLY if it is the first outlet in the circuit Certainly not a hard thing to do. and ONLY if it (the circuit and the GFCI) is wired correctly! If you can't wire it right, hire someone who can. Rod |
#94
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Rod,
I assure you that the earth as referenced by your hull is different than the the copper plated steel stake at the distribution transformer. There are rules in every country that prevent power entry equalization busses to be much longer than a meter for very good reason. Please keep in mind that an electric impulse propagates across a conductor at 2 nonoseconds per foot. In a drag race, an electric pulse will travel to a closer point faster than a further point, even without consideration of path quality. In that light, ground is not ground the world around. In real life, there can be thousands of volts in potential difference between two functioning earth references and very often is. It is one of the reasons that a lightning strike a mile away can zap all your appliances without striking your property. Ground problems are very complex, difficult to analyse and very expensive to resolve. Please also remember that wiring code only allows one reference to earth in a building. It is illegal and downright unsafe to use water pipes and other connections as well as the safety reference from the street. However, a boat is significantly different. The water makes contact with the earth across millions of square meters of surface. In comparison, the distribution transformer has only the surface area of the ground rod to use and I will point out that the quality of the connection is subject to rod corrosion and the mineral content of the soil it contacts. It is not unusual for the electric company to deposit hundred pound bags of salt around this rod in areas of poor soil conductivity and rinse the salt into the soil with water to help alleviate this problem. Commercial ships (and myself) use isolation transformers to alleviate this corrosion risk. In that way the electric energy is magnetically coupled aboard and no circuit reference exists to the power net. As an individual, you are in control of your electric domain and accept the responsibility of good practice and maintenance of the boat wiring and the appliances you use. The question you have to ask yourself is "Are you willing to accept the consequences of other people's faults and stupidity?" I am not and I do not use the earth connection at the dock. Steve "Rod McInnis" wrote in message ... "Steve Lusardi" wrote in message ... Secondly, when plugging in to shore power, never connect the safety earth line. To not connect the safety ground at the AC input plug would be in direct violation of accepted wiring for boats. If wired that way it would never pass survey and if a fire or accident happened and investigators found it wire this way it could create issues with the insurance. You could leave the boat wired properly if you modified the power cord to separate out the ground wire. It would be a shame to break the integrity of the outer jacket of the cordset, however. If this cord lays out in the weather allowing water to penetrate the jacket may eventually cause problems. Instead use a line to your boat earth for the safety connection. Where does one get a good earth connection on a dock? I suppose that you could drive a copper rod down into the ground beside your slip, and then make a connection to it with enough service loop to allow for changes in water level. You better inspect it often to assure that it hasn't corroded away. Remember, your hull will always be a better earth connection than the one from the distribution transformer for the pier or yard Can you explain what you are saying here? It sounds like you are saying that the path through the water to "ground" is always better than the path through copper wire to "ground", which is certainly not true. Rod |
#95
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Keith,
GFCI breakers make certain that outgoing current always matches incoming current. They do not monitor earth. They monitor phase to phase and phase to neutral with a bridge circuit. There should never be more than 50 milliamps of current on the safety circuit and on a boat there must be "0" amperes for corrosion reasons. On a boat, there can only be one earth reference for all loads both AC and DC. DC return is not earth, it must also be completely separate. Steve "Keith" wrote in message ... and ONLY if there is no DC current leakage, or DC grounds wired to the AC grounds. Of course, this NEVER happens. ;-) -- Keith __ Pardon my driving, I'm reloading. "John R Weiss" wrote in message news:%D8vc.3368$sI.620@attbi_s52... "Paul Schilter" paulschilter@comcast,dot,net wrote... You don't have to install a GFCI in every outlet. Just in the first outlet of the circuit, the rest that are downstream will be protected. Just have them in every circuit. ONLY if the GFCI outlet supports chaining, and ONLY if it is the first outlet in the circuit and ONLY if it (the circuit and the GFCI) is wired correctly! |
#96
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On Wed, 02 Jun 2004 04:08:59 GMT, Terry Spragg
wrote: If you install the 'right' connectors, one at bow, one at stern, you will energise the prongs sticking out of the unused one. If someone removes that weather cover, full line power is available for prying fingers. Dangerous, unless you have a switch over to select only one input plug. Perhaps I was unclear on that point: I would of course install a full break point switch between the two plugs. Either, never both. Fact is, I would use the bow plug 95% of the time as I dock bow in. When I travel, however, and am stern in or on a wall with a bit of a distance to a plug, or when I am in the cradle on the hard all winter, I would revert to the stern plug. Thanks. R. |
#97
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On Tue, 01 Jun 2004 10:15:52 -0400, Sam wrote:
Hate to barge in but there is some potentially dangerous advice in a post here. Apologies to the original poster but this is a bad idea: snip If you really DO intend to have two shore power inlets, they must be switched so that only one can ever be "in circuit" at a time. Thanks. I posted a response earlier that covered this. A manual switch would totally disconnect one plug from the other, avoiding the admittedly dangerous situation of an energised circuit. I have a two year old. I would like him to do foredeck one day. So I try to avoid electrocuting him G as it's bad for morale. And, since I have already barged in he Use tinned stranded wire for AC as well. No less than 14awg, bigger is better. There are published guidelines for current capacity/distance that should be followed, but bigger is better. I would use 10 AWG tinned stranded for a 30 amp circuit. The runs are not so long that cost is an issue. You can't go far wrong slightly oversized, as the wife notes G. Finally, install a GFCI for every AC outlet on the vessel. Already done with the existing two AC outlets in the galley and the head. Same with every new (since we bought the place in '98) outlet in my home. I got a dramatic demonstration 2 years ago, when I stepped in a puddle from showering (barefotot naturally) as I turned on an electrical device in the head. The GFCI blew instantly. Now what do you suppose would have happened to me if it hadn't popped? Your heart would have popped. GFCI's are cheap insurance. Beats waking up dead any day! They don't stand up to salt water very well though. So if you cruise in salty air, expect to replace once in a while. But GFCI's are cheap insurance as I said. Not an issue as of yet. I cruise Lake Ontario, and beer is a bigger hazard than salt water. Thanks for the warning. R. |
#98
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"Rod McInnis" wrote...
ONLY if the GFCI outlet supports chaining, Most do. In fact, I can't recall seeing any in the last 20 years that didn't. I've installed a couple, before I knew to look for it. and ONLY if it is the first outlet in the circuit Certainly not a hard thing to do. ....assuming the installer is electrical system savvy... |
#99
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![]() "Steve Lusardi" wrote in message ... Rod, Please also remember that wiring code only allows one reference to earth in a building. Are you referring to the safety ground (a non current carrying circuit) or the "neutral" ground? It is illegal and downright unsafe to use water pipes and other connections as well as the safety reference from the street. What country are you in? If you had said "instead of" I might agree with you, but my experience sure doesn't support "as well as". I admit to not being well versed in the various building codes across the USA, but I have done a fair amount of house and business wiring here in California. I have also built a number of products that are sold in the USA and have had to pass UL and CSA safety agency approval. The standard configuration that I have always encountered is that "Neutral" connects back to the power company's transformer (which usually has a connection to a copper rod driven into the ground) while the safety ground is referenced to a copper rod driven into the ground at the point of entry. In addition to the safety ground wired throughout the house it is common for certain appliances and equipment to establish a separate safety ground. This is especially important when installing equipment into older homes that were not wired with the three terminal receptacles. It is very common for the washing machine to have a extra safety ground. Dishwashers, garbage disposals, gas dryers, and other appliances that connect to both electrical and gas/water lines may establish a separate path to ground just by their very nature. Many businesses, especially those that work with sensitive electronic components, will go to elaborate steps to ground all the work benches as part of their anti-static protection. Here in the USA it is common for people to install satellite dishes on their rooftops. The standard installation kit includes a separate ground rod that provides a safety ground connection to the satellite dish. This in turn gets connected to the received via the coax cable. Likewise, cable TV introduces another version of what could be considered "ground". The shield of the cable coax is connected to ground at the cable company's equipment. This makes the entire chassis of the cable box "cable ground". If the cable box has a grounded plug then the two are connected at that point. Every piece of equipment that connects to the cable box, including the TV, VCR, stereo, etc. will then have their chassis ground referenced to some combination of house entry ground, satellite dish ground and cable company ground. It is unwise and perhaps illegal to use a water pipe as "the" safety ground. It would be very difficult to maintain isolation between separate references and here in the USA it is intentionally done all the time. However, a boat is significantly different. The water makes contact with the earth across millions of square meters of surface. Yes, but the water itself (especially freshwater) is not a perfect conductor. The amount of surface area that the water has to the ground is irrelevant as the water to earth resistance is not significant compared to the resistance of the water alone. In addition, unless you have a steel hulled boat the surface area of possibly energized parts of the boat (prop, shaft, rudder, strut, zincs and through hull fittings) will be very small. As an individual, you are in control of your electric domain and accept the responsibility of good practice and maintenance of the boat wiring and the appliances you use. I challenge the concept that breaking the accepted and standard method of grounding your boat and providing your own is "good practice". The question you have to ask yourself is "Are you willing to accept the consequences of other people's faults and stupidity?" I am not and I do not use the earth connection at the dock. You I fear most of all. Are you implying that you rely on the water to provide your safety ground connection? Or have you driven a copper rod into the earth below your dock and religiously connect it? Do you inspect this installation on a regular basis (including diving down to inspect the entire length of the rod?) If you installed an appropriate ground and maintain it properly then you will be safe. Please convert your boat back to a standard configuration before you sell it or let anyone else use it. If you are relying on the water to provide your safety ground then you are the dangerous one. Okay, you mentioned that you use an isolation transformer, which would certainly reduce the risk considerably. Without the isolation transformer, however, your advice is an accident waiting to happen. Rod |
#100
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Rod McInnis wrote:
"Steve Lusardi" wrote in message ... Rod, Please also remember that wiring code only allows one reference to earth in a building. Are you referring to the safety ground (a non current carrying circuit) or the "neutral" ground? It is illegal and downright unsafe to use water pipes and other connections as well as the safety reference from the street. What country are you in? If you had said "instead of" I might agree with you, but my experience sure doesn't support "as well as". I admit to not being well versed in the various building codes across the USA, but I have done a fair amount of house and business wiring here in California. I have also built a number of products that are sold in the USA and have had to pass UL and CSA safety agency approval. The standard configuration that I have always encountered is that "Neutral" connects back to the power company's transformer (which usually has a connection to a copper rod driven into the ground) while the safety ground is referenced to a copper rod driven into the ground at the point of entry. In addition to the safety ground wired throughout the house it is common for certain appliances and equipment to establish a separate safety ground. This is especially important when installing equipment into older homes that were not wired with the three terminal receptacles. It is very common for the washing machine to have a extra safety ground. Dishwashers, garbage disposals, gas dryers, and other appliances that connect to both electrical and gas/water lines may establish a separate path to ground just by their very nature. Many businesses, especially those that work with sensitive electronic components, will go to elaborate steps to ground all the work benches as part of their anti-static protection. Here in the USA it is common for people to install satellite dishes on their rooftops. The standard installation kit includes a separate ground rod that provides a safety ground connection to the satellite dish. This in turn gets connected to the received via the coax cable. Likewise, cable TV introduces another version of what could be considered "ground". The shield of the cable coax is connected to ground at the cable company's equipment. This makes the entire chassis of the cable box "cable ground". If the cable box has a grounded plug then the two are connected at that point. Every piece of equipment that connects to the cable box, including the TV, VCR, stereo, etc. will then have their chassis ground referenced to some combination of house entry ground, satellite dish ground and cable company ground. It is unwise and perhaps illegal to use a water pipe as "the" safety ground. It would be very difficult to maintain isolation between separate references and here in the USA it is intentionally done all the time. However, a boat is significantly different. The water makes contact with the earth across millions of square meters of surface. Yes, but the water itself (especially freshwater) is not a perfect conductor. The amount of surface area that the water has to the ground is irrelevant as the water to earth resistance is not significant compared to the resistance of the water alone. In addition, unless you have a steel hulled boat the surface area of possibly energized parts of the boat (prop, shaft, rudder, strut, zincs and through hull fittings) will be very small. As an individual, you are in control of your electric domain and accept the responsibility of good practice and maintenance of the boat wiring and the appliances you use. I challenge the concept that breaking the accepted and standard method of grounding your boat and providing your own is "good practice". The question you have to ask yourself is "Are you willing to accept the consequences of other people's faults and stupidity?" I am not and I do not use the earth connection at the dock. You I fear most of all. Are you implying that you rely on the water to provide your safety ground connection? Or have you driven a copper rod into the earth below your dock and religiously connect it? Do you inspect this installation on a regular basis (including diving down to inspect the entire length of the rod?) If you installed an appropriate ground and maintain it properly then you will be safe. Please convert your boat back to a standard configuration before you sell it or let anyone else use it. If you are relying on the water to provide your safety ground then you are the dangerous one. Okay, you mentioned that you use an isolation transformer, which would certainly reduce the risk considerably. Without the isolation transformer, however, your advice is an accident waiting to happen. Rod Well, it seems to me that once 'at sea' a vessel is isolated from external electrical distribution system threats, such as an energised earth connected to one side of a power source, requiring only a single further connection to electrocute any nearby person standing on God's natural green earth, which was provided in an un-energised state, and which no-one has the right to energise, poison, paint, or otherwise deface without having license, posting adequate warnings, and willingly paying any damage claims shown to involve current through the earth, which should be absolutely anathema. Grr. Yes, I am ****ed off about this, and I maintain that the only reason for it's defense by hydro is because of ancient legal precedent protecting them from electrocutions caused by stepping on to the face of the earth. If not for the 'earth safety neutral' connection, anyone holding the black wire in his teeth could still walk barefoot on the earth without danger. If all devices were wired in a bifilar manner only, there could be no electrocution danger from touching earth. Current cannot flow without 2 connections to the power source. One of them should not be universally mandated for the convenience of the electrical power industry, and to the detriment of every freehold citizen. The electrical industry has been hiding behind government for a century, enabled only by incorrect politicians who have made the deadly practice en 'essential' feature of the system. So, we see an early attempt to minimise wire useage costing us an extra connector, the earth return / not conductor / killing messenger and an imaginary 'neutral', or ground, by the majic of undemocratic illogical politicians and whoring lawyers, who listen to inventors, not refiners of technology. Unfortunately, no-one should claim to have invented electricity, or any of it's roots. It was discovered, and continues to be refined and universally owned, not be patentable, except for short times. It could be done differently, and doing so would not cost as much as was recently wasted in Irag. 'Double insulated' tools (which have only 2 wire plugs) is a step in the right direction farther than neccessary, and such similar practice must become the new standard for all of the industry. All chassis should be completely isolated from any electrical connection, even the dirt, as was definitely not the practice anywhere until recently. The concept of 'ground' itself is flawed. As a technician, I understand that 'ground' is purely an arbitrary standard existing only at the end of my test meter's ground (or, 'reference') probe. All AC power has a wavelenth associated with it's frequency. The voltage at one end of an AC wire is not the same as at the other, because of phase delay. At 60 hz, the wavelenght is about 3000 miles. The voltage on the AC system is not simultaneously the same say, on opposite coasts. Every generator's local reference is naturally different in time from the other's, so they can all feed into each other without burning up. The concept of ground or earth, is irrellevant at AC for power, the only important measurements that can be made are bifilar, very local, and must be understood as difficult to accomplish for flesh, unless you wire the earth itself, save for lightning. Electricians wear rubber insulated boots. Why? because barefoot, they would be in danger for only one reason, the 'safety' ground. "Modern" earth ground safety dogma is a murderous myth, defended by Edison et al to preserve their sacrosanct immunity from responsibility for originally expropriating the entire earth for use an an electrical conductor from the beginning of electrical use. An illegal theft from the beginning, unneccessary, complicating, stupid, defended by politicians, and now, even by dumbed down engineers who whole heartedly swallow the rationale they are fed in school, where free thought is rigorously stamped out by lawyers, teachers and councellors. Crazily (?) some survivors can't resist thinking freely, even *with* flourides. Doubt your foundations! You will find those you can trust, at sea, Billy! Life is dangerous. Don't let the stupid ones win. You are Darwin. Take this part of a continuing diatribe with all the salt you can afford. Borrow more. We all live on the slope of a volcano in whom's hot guts continues a juggling act involving fizzy gobs of locally slow neutrons and fluid heavy elements, all in zero gee, a spherical atomic hell, completely not understood. Get used to it. Why go to Mars? Because we can? Because some one else might? Sailors have gone to sea in ships for long voyages since wood was found to float. But should public health and education get the money instead? Would safety result? For whom? Some power structures exist best in an atmosphere of great fear. Everything is relative. Terry k |
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