| Author | Message | ||
| jjrsmp (69.135.206.67)
Rating: N/A |
Attached is the schematic of how they wired the shore power and generator power. It looks like they did not run the extra hot wire to the switch. Problem is I keep tripping the 50A breaker. I have a marinco plug, but the original wiring at the shore plug only has 3 6G wires, no ground. IS this is problem?  | ||
| jjrsmp (69.135.206.67) Rating: N/A |
Sorry for the quality. Basically, does it make sense I keep tripping the breaker? I am going to check the switch(it is under a chair in the coach) and connect the extra hot wire. Is the ground a problem? Thanks | ||
| TWO DOGS (65.177.144.21) Rating: N/A |
need that ground !!...the bus is up on rubber,when you enter or leave the bus...'YOU' make the connection | ||
| Ian Giffin (Admin) (65.92.125.244)
Rating: N/A |
jjrsmp, Email me the schematic and I'll adjust it to be readable. (click my name, above). Ian www.busnut.com | ||
| Tom Caffrey (Pvcces) (65.74.66.104)
Rating: N/A |
jjrsmp, some of the marine 50 amp cables are set up to connect the metallic outside of the plug to a ground conductor at the outlet. If you're popping a breaker, do your testing with an ohmmeter with all your circuit breakers turned off. After you show an open circuit between each pair of your conductors, then close breakers one at a time until you get a low resistance between a power wire and the neutral or between the two hot wires. If you're popping a 50 amp breaker, you're under 5 ohms across a 240 volt circuit or under 2 1/2 ohms on a 120 circuit. Watch out for transformers; they will look like a near short on an ohmmeter. I hope this helps. Tom Caffrey PD4106-2576 Suncatcher | ||
| jjrsmp (198.97.67.59) Rating: N/A |
Thanks for the replies. I have fixed the issue. Believe it or not, the wires going from the generator to the switch, and from the switch to the relay panel are Green and Black Hot, and White neutral.. HOWEVER, the wires from the shore plug to the switch are White/black HOT and Green neutral. ARGGGGGGGGG. Anyways, switched the wires at the plug and whola, everything is perfect. Thanks for the help. This is a great board... | ||
| DaveD (142.46.199.30)
Rating: N/A |
Wires should be identified by red and black hot, white neutral and green ground. It would be a good idea to get some coloured electrical tape and wrap a layer on the ends of the insulated part of each conductor so that these are easily identified. You have only identified three wires from the shore line. Where is your safety ground conductor? FWIW DaveD | ||
| Gary McFarland (Gearheadgary) (209.128.79.46)
Rating: N/A |
"some of the marine 50 amp cables are set up to connect the metallic outside of the plug to a ground conductor at the outlet." Actually, this should not be the case-- Marine shore cords should have an Isolated ground, the boat and the "Shore" should not have the same safety ground. As I say this, it makes my eyes cross a bit, and I admit that I have to refer to the book and a schematic each time I wire a marine shore connection, but two boats with the ground incorrectly wired has killed many swimmers. Now that being said, I can't remember if the isolation is built into the core/plug, or if it is up the the 'Lectrician to do it correctly. Gary | ||
| DrivingMissLazy (66.168.175.51) Rating: N/A |
In the ones that I have seen, there is a metallic tab on the outer perimeter of the plug. The plug itself is an insulating material and I do not believe there is an electrical connection between the plug body and the ground tab. Richard | ||
| Gary McFarland (Gearheadgary) (209.128.79.46)
Rating: N/A |
Yeah, I'm thinking about that, it's giving me a headache. Either that, or trying to look at that Schematic. I'm 2500 miles from my boats at the moment, so I can't say for sure. My 56 has a 50A, and I know it has the tab. I don't think any of my 30A plugs have them. I know that 50A is four-wire and the 30A is three. On mine (the 50A), I know the "2nd Hot" is taped back, because the marina end of the cord was 30A. I'm not sure if the Marine cord and RV cord are the same.... Gary | ||
| Tom Caffrey (Pvcces) (65.74.66.104)
Rating: N/A |
Gary and Richard, the shore power cords I was referring to are required in our harbor because of the recent installation of 50 amp, 120/208 power on our float. If we only need 120, there is a twist lock 30 amp outlet available at the power box. They contain four conductors, three of which are connected to conventional pins on the face of the plug. These are the two hots and the neutral and are 6 gauge. I don't know if the fourth conductor is 6 or 8 gauge, but it is connected to a shiny ring that runs all the way around the outside of the plug. The outlet has a tang or tab that presses against the outer ring when the shore power cord is plugged in. The ground isolation (galvanic isolator) is mounted in the boat and is a package of high current diodes. It intercepts the shore power before it reaches any of the boat circuits. All it does is force the ground to be different from the boat by a little over a volt before it conducts. That's usually sufficient to prevent galvanic corrosion. Since that work was done, the maintenace of the boat has really dropped. I think they had some stray power getting into the water before. For what it's worth. Tom Caffrey PD4106-2576 Suncatcher | ||
| Jim Stacy (209.247.222.91)
Rating: N/A |
JJ Green should be GROUND, never neutral and certainly NEVER hot. Where is your fourth wire (ground)? You can't make a legal 4 wire, 50 amp circuit with 3 wires. Sorry. I couldn't make out your schematic well enough to see what you had done. At the very least the wires should be identified with the proper color (tape, paint) at both ends. Best is red and black for the two hot lines, white for neutral, green for ground. I suspect you know to keep the white and green separate in your breaker box. Stay safe. Jim Stacy | ||
| Gary McFarland (Gearheadgary) (68.252.9.119)
Rating: N/A |
"recent installation of 50 amp, 120/208 power on our float." Really? 120 and 208 in the same service? So--I went looking for the ABYC regs on Ground Isolation, and I see that Galvanic Isolation is now an approved safety isolater too, as long as it's combined with a polarity detector. Hmm. I'm not talkind about Galvanic Isolation though, but Safety Isolation. In any case, none of this has anything to do with the original post. jjrsmp--do you have a 220 connection? Gary | ||
| DrivingMissLazy (66.168.175.51) Rating: N/A |
Three phase 208/120 wye is a very common electrical configuration, especially in locations where there are lots of computer or other high tech equipment. Very common in high rise buildings. It is much easier to distribute the 120 volts and keep a balanced load with this system as opposed to the more common industrial three phase 240/120 volt delta connected power. Especially when the majority of power required is at 120 volts. I was not aware that it had progressed into the marine power systems. It does make sense though. Most of the larger luxury yachts I am familiar with require three phase power and also have a lot of 120 volt power requirements. Richard | ||
| jjrsmp (198.97.67.59) Rating: N/A |
Yes, there is a 4th ground wire, smaller gauge than 6. It is connected and grounded. | ||
| Richard Bowyer (Drivingmisslazy) (66.168.168.57)
Rating: N/A |
I strongly suspect there are Three hots (phase A, Phase B and Phase C) a neutral and a ground for a total of five conductors. 120 volts is available from any phase to neutral, and 208 volts between any two phases. Richard | ||
| Tom Caffrey (Pvcces) (65.74.66.104)
Rating: N/A |
Richard, I don't know of anyone using three phase on our float, yet. Each of the power boxes has two meters in it, however. I can see that if the two bases use a different phase, it would not take much to convert any of them to three phase without any additional wiring. Gary, as far as I can tell, the main difference between marine and RV shore power connectors is the marine are twist-lock and the RV are straight pins. For what it's worth. Tom Caffrey PD4106-2576 Suncatcher | ||
| Gary McFarland (Gearheadgary) (68.250.174.11)
Rating: N/A |
208 is a product of any two hot legs of a three phase wye service. Although you can get 120 from any one leg to common, I have never seen 120 used from a three phase supply, but rather the product of a 440V three-phase driven transformer. Not sure why, wasn'tmy job to know. After a little nosing around, I guess marinas are starting to provide 3-phase. Marine connectors are the same as non-marine, Aside from Hoods, etc... I think NEMA L10-50, but that's from memory. RV's don't use twist lock? Really? Gary | ||
| DrivingMissLazy (66.168.175.51) Rating: N/A |
Gary, most high rise office buildings are wired for 208/120 due to the proliferation of PC loads. In the earlier years, all the large mainframe computers were 208/120 volt three phase also. There are many instances where the main power feed into a building is 460 volt, three phase or higher, up to 4400 volts and maybe even 7200 volts, with step down distribution transformers installed on each floor to step the voltage down to 208/120. I have worked at literally hundreds of marinas throughout the world and I do not recall any that did not have three phase power, however it was not generally apparent. Typical wiring was to bring two phases to a power pedestal, for example phases A and B. The next pedestal would have phases B and C and the next pedestal would have phases C and A. This way the distribution would generally be fairly evenly loaded. For the yachts that needed three phase power we generally had to run a shore cord to two different power pedestals. The newer marinas that cater to yachts over 80-100 feet all have three phase power at each pedestal. Below is a link to some of the equipment I developed and manufactured for many years. http://www.shorpower.com/products/tecpower/index.shtml Richard | ||
| Gary McFarland (Gearheadgary) (68.250.174.11)
Rating: N/A |
Most commercial lighting systems are 208, I'm familiar with the power requirements of mainframe/Minicomputer systems, however my role with them has involved a forklift and a dumpster. I was just saying that I've never seen an "Outlet" with both 208 and 120 available. None of the marinas I've been (Or Lived) in had 3phase, but then again none had slips over 72' My own vessel of 56' was usually one of the biggest in the marina. Gary |