Generator wiring question

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Old 05-09-06, 01:25 PM
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Generator wiring question

I just bought a Chinese 6.5 KW copy of a Honda that I want to use for emergency power for my house. It appears to have a floating neutral as there is no continuity between the neutral and ground. My problem is that when I plug a receptacle tester into it all three lamps light, and the chart doesnít show this combination. Is this normal for a generator, or is the unit wired wrong? I have tested it with an angle grinder and a heater, and it does work.

Thanks, Ross
 
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Old 05-11-06, 11:04 AM
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By the way the tester is an Etcon CT102
 
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Old 05-11-06, 12:20 PM
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First, what is the voltage output of the generator? 120V only or 120/240? What type of receptacle(s) does it have?

Do you have a voltmeter to measure all combinations of voltage at the receptacle: slit-to-slit, slit-to-ground, other slit-to-ground?
 
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Old 05-11-06, 01:48 PM
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i just want to give you a head up about the generators this is pretty common for most i will say most small generators are self regulated and they dont make very clean " power " at all and many generators when running without load the voltage will read little higher than normal.

that is very typical for this to do this but most small generators genrally do have floating netrual but if the generator did came with GFCI it should work correct way but if not some case they will add a jumper between netrual and ground to get the frame grounded.

please check with your manual to see if more answer in there and what kind of " chinese " knock off type like what brand name it is may be i can able to pinpoint about this sisuation


Thanks

Merci , Marc
 
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Old 05-13-06, 01:15 PM
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The unit is made by Yancheng Best Engine manufacturing works. http://www.best-engine.com/bestdh/ga.../generator.htm It is model G-60L(D) and is 120/240. The 120 volt side has two 5-20 and one L5-30 outlets. The 240 volt side has one L14-30. I just checked the voltage, Neutral-hot=120V, hot-ground=50V, neutral-ground=70V. That seems odd.

Thanks for the replies, Ross
 
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Old 05-13-06, 01:19 PM
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Why does that seem odd? You have already determined that the neutral and ground are not connected. Therefor the readings you are getting between a hot wire or the neutral wire and ground are meaningless.
 
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Old 05-13-06, 05:35 PM
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Sorry, Iím a machinist not an ďElectrical/Computer Engineer BobĒ, I just want to know if itís going to work or if itís going to fry something.
 
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Old 05-15-06, 12:38 PM
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Sounds like your unit is wired normally. How do you plan to use it for emergency power? Will you be installing a transfer switch/panel or simply plug the important equipment into the generator when needed?
 
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Old 05-16-06, 11:06 AM
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To bond or not to bond

If the loads you will supply will be connected via cord and plug only then you should add a bonding jumper between the neutral and the frame of the generator set. If you are going to connect it to your homes wiring via a transfer switch then you should leave it unbonded. If you are going to use it for both types of load the answer is more complicated.
 
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Old 05-20-06, 10:53 AM
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Iíll be using a transfer switch/panel with a 240V 30A extension cord between the generator and panel. I want to run the well pump, refrigerator, lighting circuits, etc. Would it be safe to run a TV/DVD, or is the power too dirty? The power can go out for days at a time here so the kids (and wife) can get pretty bored.

Thanks, Ross
 
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Old 05-20-06, 11:00 AM
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You may not have enough power for the pump.

I would not run ANY electronic equipment on generator power unless I ran the power through a good quality UPS first.
 
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Old 05-20-06, 10:18 PM
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Which type of UPS

The kind of UPS you would need would be the continuous duty type rather than the switching type. Those are more expensive but they provide a much greater degree of isolation from the generator power.
 
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Old 05-20-06, 10:47 PM
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My 3-lamp tester does the same light combo with the 120V inverters in my trucks. Same reason. Work fine.
 
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Old 05-20-06, 11:04 PM
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NUFF said.

You should have the frame (of the generator) grounded when on the generator.
Due to the fact that the generator is ISOLATED.
Make sure all legs of the regular system are OPEN.

You don't want to backfeed the power co. That could Kill someone.
 
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Old 05-21-06, 10:45 AM
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Iíve run the well pump plus lights with a smaller 3.8kw generator without a problem. Itís a shallow well with an above ground jet pump, so I guess it doesnít draw too much.

Lectriclee- I assume you mean the frame should be grounded to a post in the ground. There is a grounding post near where the generator will be located, can I just tie into it?

Thanks for the replies, Ross
 
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Old 05-21-06, 02:43 PM
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Bonding verses grounding

Originally Posted by roscodog
Iíve run the well pump plus lights with a smaller 3.8kw generator without a problem. Itís a shallow well with an above ground jet pump, so I guess it doesnít draw too much.

Lectriclee- I assume you mean the frame should be grounded to a post in the ground. There is a grounding post near where the generator will be located, can I just tie into it?

Thanks for the replies, Ross
Speaking only for myself I was talking about bonding the neutral of the generators winding to the frame of the generator. This provides a connection between the "Equipment Grounding Conductors" (EGCs) of the connected circuits; which are really equipment bonding conductors; and the generators winding. The purpose of that connection is to allow any fault between the normal current carrying parts of the circuit and the non current carrying conductive parts of the electrical system to result in excess current flow which trips the circuits Over Current Protective Device; i.e. a fuse, circuit breaker, or thermal cut out. In the absence of a bonding connection those normally harmless metallic parts of the electrical system can be energized and waiting for you to touch them and receive a possibly dangerous shock. In order to make that connection it may be necessary to remove protective covers from the generator head or it's wiring box. The US National Electric Code requires that a generator that supplies cord and plug connected loads from outlets mounted on the generator must have the generator outlet's grounding terminal bonded to the neutral and the frame. If the generator is supplies outlets on a vehicle then the the bonding must include the vehicle frame. The conflict comes when the generator supplies a buildings built in wiring. The neutral of the buildings wiring is bonded to the enclosure of the buildings disconnecting means and grounded near that same point. If the neutral of the generator is also bonded to the EGC of the cord that supplies the building then the neutral current will be flowing over both conductors and a bad connection or voltage drop in the neutral could raise the potential on conductive surfaces to dangerous levels. The two ways to avoid that possibility are to leave the EGC unbonded at the generator or to disconnect the buildings EGCs from the neutral at the building disconnecting means. If the generator will only be used to power the building then leaving it's neutral unbonded is the easiest way. If the generator will be used to power cord and plug connected loads from outlets that are not part of the buildings wiring then you need to have a ready means to open the bonding jumper at the generator or at the building disconnecting means. If it is done at the building disconnecting means the changeover from public power to the generator inlet must open the buildings main bonding jumper prior to or simultaneously with the transfer of the other connections. I'm sure you can see that it is easier to do this at the generator.
 
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